Alternatives to Methyl Bromide

Transcription

1 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide United Nations Environment Programme Division of Technology, Industry and Economics OzonAction Programme

2 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Acknowledgments This publication was produced by the United Nations Environment Programme Division of Technology, Industry and Economics (UNEP DTIE) as part of its OzonAction Programme under the Multilateral Fund. The team at UNEP DTIE that managed this publication was: Jacqueline Aloisi de Larderel, Director, UNEP DTIE Rajendra Shende, Chief, Energy and OzonAction Unit, UNEP DTIE Cecilia Mercado, Information Officer, UNEP DTIE Corinna Gilfillan, Associate Programme Officer, UNEP DTIE Susan Ruth Kikwe, Programme Assistant, UNEP DTIE Project Administration: The Danish Institute of Agricultural Sciences Author: Dr Melanie Miller, Member of MBTOC Editor: Velma Smith Technical reviewers: Dr Jonathan Banks, Dr Tom Batchelor, Prof Rodrigo Rodríguez-Kábana Editorial reviewers: Mr Jorge Leiva, Ms Jessica Vallette Design and layout: ampersand graphic design, inc. UNEP DTIE would like to thank the following individuals and organisations for contributing technical information and/or contact addresses: Dr Jonathan Banks, Mr Marten Barel, Dr Tom Batchelor, Dr Antonio Bello, Mr F Benoit, Prof Mohamed Besri, Dr Clyde Elmore, Dr Peter Förster, Mr Jan van S Graver, Prof ML Gullino, Dr Volkmar Haase, Dr Saad Hafez, HortResearch, International Institute of Biological Control, Prof Jaacov Katan, Dr Jürgen Kroschel, Dr López, Dr Gerhard Lung, Mr Henk Nuyten, Ms Marta Pizano, Prof Rodrigo Rodríguez-Kábana, Eng. Rafael Sanz, Ms Velma Smith, Dr Anne Turner, and other specialists and agricultural suppliers in many countries. This document is available and will be periodically updated on the UNEP OzonAction website at: UNEP This publication may be reproduced in whole or in part and in any form for educational or non-profit purposes without special permission from the copyright holder, provided acknowledgement of the source is made. UNEP would appreciate receiving a copy of any publication that uses this publication as a source. No use of this publication may be made for resale or for any other commercial purpose whatsoever without prior permission in writing from UNEP. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsover on the part of the United Nations Environment Programme concerning the legal status of any country, territory, city or area or of its authorities, or concerning delimitation of its frontiers or boundaries. Moreover, the views expressed do not necessarily represent the decision of the stated policy of the United Nations Environment Programme, nor does citing the trade names or commercial processes constitute endorsement. UNITED NATIONS PUBLICATION ISBN:

3 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide United Nations Environment Programme Division of Technology, Industry and Economics OzonAction Programme

4 Disclaimer This document has followed the general format for other Sourcebooks of ozone protection technologies developed by the United Nations Environment Programme Division of Technology, Industry and Economics (UNEP DTIE). UNEP, its consultants and reviewers of this document and their employees do not endorse the performance, worker safety or environmental acceptability of any of the technical options described in this document. While the information contained herein is believed to be accurate, it is of necessity presented in a summary and general fashion. The decision to implement one of the alternatives presented in this document is a complex one that requires careful consideration of a wide range of situation-specific parameters, many of which may not be addressed by this document. Responsibility for this decision and all of its resulting impacts rests exclusively with the individual or entity choosing to implement the alternative. UNEP, its consultants and reviewers of this document and their employees do not make any warranty or representation, either express or implied, with respect to its accuracy, completeness or utility; nor do they assume any liability for events resulting from the use of, or reliance upon, any information, material or procedure described herein, including but not limited to any claims regarding health, safety, environmental effects, efficacy, performance or cost made by the source of the information. The lists of vendors provided in this document are not comprehensive. Mention of any company, association or product in this document is for informational purposes only and does not constitute a recommendation of any such company, association or product, either express or implied, by UNEP, its consultants, the reviewers of this document or their employees. The reviewers listed in this document have reviewed one or more interim drafts of this document but have not reviewed this final version. These reviewers are not responsible for any errors that may be present in this document or for any effects that may result from such errors.

5 Table of Contents List of tables, boxes and figures...vi Foreword Introduction...3 Methyl Bromide...3 Purpose of the Sourcebook...4 Contents of the Sourcebook...4 How to use this Sourcebook Guidance for selecting non-ods technologies...9 Selecting and evaluating alternatives...9 Organisational considerations...9 Technical considerations...10 Economic considerations...10 Regulatory considerations...11 Health and safety considerations...12 Market and consumer considerations...13 Environmental considerations Control of soil-borne pests...15 MB-based control...18 Overview of alternative pest control techniques...18 Examples of alternatives in commercial use...19 Uses without alternatives...19 Strategies for controlling pests...21 Crops and crop production systems...25 Identifying suitable alternatives Alternative techniques for controlling soil-borne pests IPM and cultural practices...29 Importance of IPM and combined techniques...29 Components of IPM...29 Cultural practices...30 Hygienic practices...30 Crop rotation...31 Resistant varieties and grafting...33 Mulches and cover crops...33 Nutrient management...33 Time of planting...33 Trap crops...33 itable of Contents

6 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide ii Water management...35 Specialists and information resources Biological controls...38 Advantages and disadvantages...38 Technical description...38 Current uses...42 Variations under development...42 Material inputs...42 Factors required for use...42 Pests controlled...42 Yields and performance...44 Other factors affecting use...44 Registration and regulatory restrictions...45 Suppliers of products and services Fumigants and other chemical products...51 Advantages and disadvantages...51 Technical description...51 Current uses...55 Variations under development...55 Material inputs...55 Factors required for use...55 Pests controlled...56 Yields and performance...57 Other factors affecting use...57 Suppliers of products and services Soil amendments and compost...61 Advantages and disadvantages...61 Technical description...61 Current uses...64 Variations under development...65 Material inputs...65 Factors required for use...65 Pests controlled...65 Yields and performance...66 Other factors affecting use...66 Suppliers of products and services Solarisation...70 Advantages and disadvantages...70 Technical description...70 Current uses...74 Variations under development...75 Material inputs...75 Factors required for use...75 Pests controlled...75 Yields and performance...75 Other factors affecting use...75 Suppliers of products and services Steam treatments...79 Advantages and disadvantages...79

7 Technical description...79 Current uses...82 Variations under development...82 Material inputs...82 Factors required for use...82 Pests controlled...82 Yields and performance...83 Other factors affecting use...83 Suppliers of products and services Substrates...87 Advantages and disadvantages...87 Technical description...87 Current uses...90 Variations under development...91 Material inputs...91 Factors required for use...91 Pests controlled...92 Yields and performance...92 Other factors affecting use...92 Suppliers of products and services Control of pests in commodities and structures...97 Types of commodities and structures...97 Durable products...97 Perishable commodities...97 Structures...97 Pests in durable commodities...97 Pests in perishable commodities...99 Pests in structures Overview of alternatives Commercially available alternatives Uses without alternatives Identifying suitable alternatives Alternative techniques for controlling pests in commodities and structures IPM and preventive measures Pest management for durables and structures Preventive measures for perishable commodities Specialists and suppliers of IPM services Cold treatments and aeration Advantages and disadvantages Technical description Current uses Material inputs Factors required for use Pests controlled Other factors affecting use Suppliers of products and services Contact insecticides Advantages and disadvantages Table of Contents iii

8 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Technical description Current uses Variations under development Material inputs Factors required for use Pests controlled Other factors affecting use Suppliers of products and services Controlled and modified atmospheres Advantages and disadvantages Technical description Variations under development Material inputs Factors required for use Pests controlled Current uses Other factors affecting use Suppliers of products and services Heat treatments Advantages and disadvantages Technical description Current uses Variations under development Material inputs Factors required for use Pests controlled Other factors affecting use Suppliers and specialists Inert dusts Advantages and disadvantages Technical description Current uses Variations under development Material inputs Factors required for use Pests controlled Other factors affecting use Suppliers and specialists Phosphine and other fumigants Advantages and disadvantages Technical description Current uses Variations under development Material inputs Factors required for use Pests controlled Other factors affecting use Suppliers and specialists iv

9 Annex 1 About the UNEP DTIE OzonAction Programme Annex 2 Glossary, acronyms and units Annex 3 Chemical safety data sheets Annex 4 Annex 5 Annex 6 Annex 7 Steps for identifying appropriate alternatives Information resources Address list of suppliers and specialists in alternatives References, websites and further information Annex 8 Index Annex 9 Contacts for Implementing Agencies A Word from the Chief of UNEP DTIE Energy and OzonAction Unit...inside back cover vtable of Contents

10 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide vi List of Tables, Boxes and Figures Table 1.1 Major applications of MB fumigant...3 Table 1.2 Montreal Protocol control schedules for MB phase out...4 Figure 1.1 Breakdown of MB applications...5 Figure 1.2 Using the Sourcebook...8 Table 3.1 Soil-borne nematode pests controlled by MB in various regions of the world...16 Table 3.2 Soil-borne fungal pests controlled by MB in various regions of the world...16 Table 3.3 Soil-borne bacteria and virus pests controlled by MB in various regions of the world...17 Table 3.4 Soil-borne insect pests controlled by MB in various regions of the world...17 Table 3.5 Weeds controlled by MB in various regions of the world...17 Table 3.6 Range of soil-borne pests controlled by MB and alternative techniques...18 Table 3.7 Overview of efficacy and timing of pest control techniques and examples of appropriate combinations of techniques...20 Table 3.8 Summary of Techniques in widespread use in some countries...21 Table 3.9 Cucurbits: melons, watermelons, courgettes (zucchini), cucumbers: examples of alternatives in commercial use...21 Table 3.10 Tomatoes and peppers: examples of alternatives in commercial use...22 Table 3.11 Strawberries (runner and fruit production): examples of alternatives in commercial use...22 Table 3.12 Cut flowers: examples of alternatives in commercial use...23 Table 3.13 Roses: examples of alternatives in commercial use...23 Table 3.14 Tobacco seedlings: examples of alternatives in commercial use...23 Table 3.15 Nursery crops (vegetables and fruit): examples of alternatives in commercial use...24 Table 3.16 Perennial crops such as banana, orchard trees, vines (re-plant): examples of alternatives in commercial use...24 Table Examples of crops for which IPM systems are used commercially...30 Table Efficacy and timing of various cultural practices...31 Box Examples of preventive practices for soil-borne pests: nematode management...31 Box Examples of preventive practices for soil-borne pests: disease management...32 Box Examples of preventive practices for soil-borne pests: weed management...32 Table Examples of suppliers of resistant varieties, rootstocks for grafting and disease-free planting materials...34 Table Examples of specialists and consultants in preventive methods and integrated management of soil-borne pests...36 Table Examples of commercial use of biological controls (normally combined with other techniques)...39 Table Examples of biological control agents and formulations for soil-borne diseases...40 Table Characteristics of several groups of biological controls...41

11 Table Examples of nematode pests controlled or suppressed by biological controls...42 Table Examples of soil-borne fungi and bacteria controlled or suppressed by biological controls...43 Table Examples of insect pests (soil-dwelling larvae and pupae) controlled or suppressed by biological controls...44 Table Examples of companies that supply biological control products and services...46 Table Comparison of technical characteristics of selected fumigants...52 Table Efficacy of fumigants and pesticides...53 Table Examples of commercial use of fumigants...54 Table Examples of yields from fumigants and pesticides...56 Table Examples of fumigants producers and specialists...59 Table Mechanisms in the control of Verticillium dahliae in soil following the addition of nitrogen-rich amendments...61 Table Examples of commercial use of soil amendments (normally used with other techniques)...63 Table Comparison of yields from soil amendments and other techniques versus MB...64 Table Examples of companies that supply products and services for soil amendments and compost...67 Table Length of solarisation treatment required to kill 90 to 100% of Verticillium dahliae sclerotia at various soil depths in Israel...70 Table Examples of commercial use of solarisation...71 Table Nematodes controlled by solarisation, California, USA...72 Table Fungi and bacteria controlled by solarisation, California USA...72 Table Weeds controlled by solarisation, California USA...73 Table Examples of nematodes, weeds and fungi and bacteria that are not controlled effectively by solarisation...74 Table Examples of yields from solarisation and MB...74 Table Examples of suppliers of solarisation products and services...77 Table Comparison of steam techniques for greenhouses...80 Table Examples of commercially used steam treatments...80 Table Examples of steam treatments required to kill soil-borne pests...81 Table Examples of suppliers of products and services for steam and heat treatments...85 Table Characteristics of various substrate materials...87 Table Comparison of two substrate systems...89 Table Examples of commercial use of substrates...90 Table Examples of yields from substrates...91 Table Examples of suppliers of products and services for substrates...94 Table 5.1 Principal pests of cereal grains and similar durable commodities...98 Table 5.2 Examples of quarantine pests found on perishable commodities...99 Table 5.3 Examples of pests fumigated with MB in structures Table 5.4 Effective techniques for pest suppression and pest elimination (disinfestation) in commodities and structures Table of Contents vii

12 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide viii Table 5.5 Examples of alternatives used for durable commodities Table 5.6 Examples of quarantine treatments approved for perishable commodities Table 5.7 Examples of alternative techniques used for structures Table Examples of pest-free zones that are accepted instead of quarantine treatments Table Examples of combined alternative treatments for commodities and structures Table Examples of specialists, consultants and suppliers of services for IPM and preventive pest management techniques Table Examples of commercial use of cool and cold treatments Table Comparison of aeration, cold treatments and freezer treatments Table Examples of quarantine treatment schedules utilising cold treatments Table Products where cold treatments are approved as quarantine treatments Table Suppliers of products and services for cold treatments Table Comparison of contact insecticides with fumigants Table Examples of commercial use of contact insecticides Table Examples of suppliers of products and services for contact insecticides Table Comparison of hermetic storage, nitrogen and carbon dioxide treatments Table Carbon dioxide disinfestation schedules for stored grain in Japan Table Examples of commercial use of controlled and modified atmospheres Table Examples of specialists and suppliers of products and services for controlled and modified atmospheres Table Examples of commercial use of heat treatments Table Temperatures for killing pests of stored products and structures Table Examples of heat treatments approved for quarantine purposes for durable commodities and artifacts, USA Table Examples of heat treatments approved for quarantine purposes for perishable commodities, USA Table Examples of specialists and suppliers of products and services for heat treatments Table Examples of commercial use of inert dusts Table Pests that can be controlled by certain DE formulations examples from USA Table Examples of specialists and suppliers of products and services for inert dusts Table Physical and chemical properties of various fumigants compared with MB Table Comparison of suitability of MB and various fumigants for grain Table Examples of commercial use of fumigants Table Minimum treatment time for phosphine fumigation of various stored product pests (all stages) Table Approved quarantine treatments for durable commodities examples from USA (USDA-APHIS) Table Examples of specialists and suppliers of products and services for fumigants...160

13 Foreword The threats of a depleted ozone layer and the binding Montreal Protocol have stirred unprecedented action around the world. Already, industries and manufacturers around the world are replacing many ozone depleting substances (ODS) with less damaging substances and practices. However, more remains to be done. The ozone layer is not yet healed. Methyl bromide, a potent pest control chemical, was identified as an ODS in In 1997, countries agreed to the Montreal Amendment to the Protocol that established a global schedule to eliminate methyl bromide use and production. Developed countries will phase out MB by 2005 while developing countries are committed to eliminate it by The phase out of this toxic chemical - widely used in agriculture and other sectors by both large and small enterprises - presents a special challenge. To replace methyl bromide, many users around the world must have access to reliable and useful technical information on non-ozone-depleting alternatives. They must learn how to select appropriate options and be able to identify and locate worldwide suppliers of information, equipment and products. Some will also require additional technical and/or financial assistance made possible by the Protocol s Multilateral Fund, which was specifically created to help developing countries fulfill their obligations to eliminate ODS use. and training. Accordingly, UNEP considers the methyl bromide phase out to be a priority. UNEP has prepared this Sourcebook to provide critical technical descriptions of the range of methyl bromide alternatives, data on cost and efficacy, and an outline of advantages and disadvantages of each option. Extensive tables, reference lists, and annexes provide readers with practical information, including names and addresses of businesses and individuals who are experts, as well as vendors of products and services related to methyl bromide alternatives. This publication is part of a package of resources (videos, awareness-raising brochures, policy and training manuals, etc.) developed by UNEP to promote the methyl bromide phase out. Using this sourcebook, current users of methyl bromide will be able to carefully and thoroughly assess many available alternatives and decide on the best option for their situation. Collectively, these informed decisions can promote a rapid and successful phase out of methyl bromide, thereby protecting the earth s ozone layer, agricultural production and, importantly, the economic interests of methyl bromide users. Jacqueline Aloisi de Larderel Director, Division of Technology, Industry and Economics UNEP UNEP is committed to continue its efforts to enable developing countries to meet these challenges with funding from the Multilateral Fund. Because of the nature of methyl bromide use, many activities to control consumption will be related to knowledge building 1Foreword

14 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 2

15 1 Introduction Methyl Bromide In many parts of the world, methyl bromide (MB) helps to control a wide range of pests, such as soil nematodes and insects in stored products. It is used mainly in the production of high value crops like strawberries and tomatoes, while lesser amounts are used for grains and traded commodities (Table 1.1). In 1997, global production of MB was about 71,400 tonnes, with an estimated 68,650 tonnes used for agricultural and related purposes, and the remaining 2,750 tonnes used as a feedstock for chemical synthesis. Sale and consumption of MB around the globe increased at a rate of about 3,700 tonnes per year between 1984 and MB is a versatile pesticide that is effective against a broad spectrum of pests. It is relatively easy to use and penetrates into soil, commodities and structures, reaching the more inaccessible pests. Effective against most pests at moderate concentrations, MB provides a relatively rapid treatment. On the downside, MB can alter the colour and smell of certain commodities; it produces bromide ion residues - a cause of concern if they accumulate in food or water; and it is highly toxic to humans, requiring special training and equipment (MBTOC 1994). MB is also a powerful ozone depletor, and in 1992 it was added to the list of ozonedepleting substances (ODS) controlled by the Montreal Protocol, an international agreement aimed at protecting the earth s ozone layer. In 1997, governments around the world established a global phase-out schedule for MB: industrialised countries will phase out MB by 2005, while developing countries will phase it out by 2015 (see Table 1.2). Table 1.1 Major applications of MB fumigant Structures & Soil Durable Products Perishable Products Transport Pre-plant: fumigation Storage: fumigation of Quarantine: Structures: fumigation prior to planting crops eg. stored products eg. fumigation of traded of buildings eg. food strawberries, tomatoes, grains, dried fruits perishable commodities processing facilities, peppers eg. fresh fruits flour mills Re-plant: fumigation Export/import and Transport: fumigation prior to re-planting quarantine: fumigation of transport vessels perennial crops eg. of traded commodities) eg. ships aircraft, fruit trees, vines eg. grains, logs freight containers Seedbeds and nurseries: fumigation prior to planting seeds & propagation materials 3Section 1: Introduction

16 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 4 MB used for quarantine and pre-shipment (QPS) purposes is exempt from Protocol controls. However, Denmark phased out QPS uses of MB by 1998, and the European Union has decided to restrict QPS consumption. Experts estimate that global QPS consumption has increased (TEAP 1999), and QPS may become controlled by the Protocol in the future. A decision under the Protocol in 1999 makes it mandatory for governments to report data on the amount of MB used for QPS. Technically feasible MB alternatives have been identified for more than 90% of MB applications. These include a variety of chemical and non-chemical measures and carefully selected combinations of several techniques linked together in an approach called Integrated Pest Management or IPM. Table 1.2 Montreal Protocol control schedules for MB phase out Developed countries Developing countries 1991: base level average: 1995: freeze (1) base level 1999: 75% of base 2002: freeze (1) 2001: 50% of base 2003: review of reductions 2003: 30% of base 2005: 80% of base 2005: phase out (2) 2015: phase out (2) (1) QPS applications as defined by the Protocol are currently exempt from reductions and phase out. (2) Limited exemptions may be granted for critical and emergency uses. Purpose of the Sourcebook The aim of this Sourcebook is to assist MB users to phase out their use of the fumigant by providing: Information about major technical options, particularly techniques that are in commercial use. Questions for users to consider when selecting alternatives. Addresses of experts and product suppliers. Sourcebook information is based on the alternatives identified by UNEP s Methyl Bromide Technical Options Committee (MBTOC) (MBTOC 1994, 1998). Specialist information and technical details were compiled by contacting scientists and extension specialists in the relevant areas of agricultural technology. In addition, surveys were conducted in many countries to identify suppliers of alternative products and services. Contents of the Sourcebook MB is used primarily as a soil fumigant to control soil-borne pests such as nematodes, fungi and weeds. It is also used for controlling stored product pests and quarantine pests in import/export commodities, such as grain and timber. To a lesser extent it is applied to buildings and transport, such as food storage facilities and ships. The major applications of MB are broken down in Figure 1.1. The Sourcebook divides MB uses into two major groups: Soil uses. Stored products, traded commodities, structures and transport. For each of the two groupings, the Sourcebook covers the following areas: General guidance for selecting non-ods techniques. Importance of pest identification and management. Description of major alternative techniques. Efficacy, uses and limitations of each alternative technique. Lists of material inputs and suppliers. Questions to consider when selecting specific alternatives. Sources of further information.

17 Figure 1.1 Breakdown of MB applications Seedbeds, nursery beds Tobacco Forest trees Turf Nursery Plants Citrus Coffee, tea Potting Media Soil Fumigation Soil-borne pests Greenhouses, plastic tunnels Field crops Cut flowers Tomatoes Peppers Eggplant Melons Cucumber, Zucchini Strawberries Root crops Herbs Perennial crops Vines Pomefruit trees Stonefruit trees Nut trees Banana plants Golf courses Flowers, e.g., roses Durable Commodities Stored product pests, quarantine pests Fixed facilities, e.g., chambers, stores Temporary facilities, e.g., docksides In transport vessels, e.g., barges, ships Grains Pulses, Beans Seeds for planting Nuts Dried Fruit Spices, Herbs Tea, Coffee Cocoa Tobacco Logs Wood products Artifacts Packaging Perishable Commodities Structures and transport Quarantine pests primarily Stored product pests, wood & quarantine pests Fixed fumigation chambers Tarpaulins, temporary facilities Storage, processing facilities Transportation Fresh fruit Vegetables Cut flowers Storage facilities Food facilities Freight containers Ships, Aircraft Bulbs Propagation Materials Flour & feed mills Buildings Other transport 5Section 1: Introduction

18 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 6 The information is arranged in the following sections: Section 2 provides general guidance for selecting non-ods techniques. It outlines the criteria to be considered when evaluating alternative options and offers a framework for organising the wealth of information that might be considered for selection of MB alternatives. Section 3 discusses generally the control of soil-borne pests. It identifies the main groups of soil pests, outlines the major strategies for controlling pests and provides steps for identifying effective alternatives for a given situation. It also provides examples of alternatives that are in commercial use in diverse countries. Section 4 describes the major alternatives for soil-borne pests. After a description of IPM and cultural practices (Section 4.1), it describes the following techniques in alphabetical order: Biological controls (Section 4.2). Fumigants and other chemical products (Section 4.3). Soil amendments and compost (Section 4.4). Solarisation (Section 4.5). Steam treatments (Section 4.6). Substrates (Section 4.7). For each, it outlines suitable applications and provides examples of companies that supply alternative products, as well as specialists and sources of further information. Section 5 discusses generally the control of pests in commodities and structures. It identifies the main groups of commodities and structures and their principal pests. It provides an overview of the range of alternatives to disinfest and protect commodities and structures from pest damage, notes the MB uses for which alternatives are not currently available and recommends steps to be used in identifying suitable alternatives. It also provides examples of alternatives which are in commercial use in various countries. Section 6 describes the major alternatives for stored products, traded commodities and structures. It starts with a brief description of IPM and preventive measures (Section 6.1). This section includes examples of practical activities which prevent pest populations thriving. The following techniques are described in more detail: Cold treatments and aeration (Section 6.2). Contact insecticides (Section 6.3). Controlled and modified atmospheres (Section 6.4). Heat treatments (Section 6.5). Inert dusts (Section 6.6). Phosphine and other fumigants (Section 6.7). For each, it outlines suitable applications and provides examples of companies that supply alternative products, as well as specialists and sources of further information. The Annexes provide additional information, including references and addresses: Information about the UNEP DTIE Ozon- Action Programme (Annex 1). Glossary, acronyms and units (Annex 2). Chemical safety data sheets (Annex 3). Steps for identifying appropriate alternatives (Annex 4). Information resources (Annex 5). Address list of suppliers and specialists in alternatives (Annex 6). References, websites and other sources of information (Annex 7). Index (Annex 8).

19 How to use this Sourcebook The flowchart labeled Figure 1.2 can serve as a guide for using the Sourcebook. The recommended approach is to begin with Section 2, which offers general guidance on selecting non-ods techniques. From there you may decide whether you are interested in controlling pests in soil, stored products, traded commodities or structures (see Figure 1.2). For soil and pre-plant uses of MB, read Sections 3 and 4 for information about alternatives. For stored products, traded commodities, such as grain, and structures, read Sections 5 and 6 for information about alternatives. For each major alternative technique covered, the Sourcebook provides information on the following topics: The pests it controls. Current uses. A brief technical description. Main equipment and materials required. Information on efficacy and performance. Suitable climates and crops. Safety aspects. Environmental impacts. Regulatory and market issues. Questions to ask about the system. Cost considerations. Lists of suppliers of relevant services and products. Other useful contacts. References (provided in Annex 7). It is recognised that the alternatives often have to be adapted when applied to new regions and situations. When you have read the relevant alternative techniques section, make a note of the options that seem to hold promise for your situation and draw up a list of information you already have and questions that need to be answered. You may find it useful to work through the tables in Annex 4, which contain detailed steps for evaluating options and selecting the most appropriate technique for a given situation. When you have identified areas for which you need more information, read the tables of specialists and suppliers, and review the references and other information resources listed in Annex 5. The addresses of companies and specialists are listed alphabetically in Annex 6. 7Section 1: Introduction

20 Figure 1.2 Using the Sourcebook Start Read Section 2 and the Disclaimer. Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 8 In which sector is your application of methyl bromide??? Durable products, perishable products or structures Read Sections 5 and 6 Read Sections 3 and 4 No Select the appropriate alternative for demonstration and/or adaptation and adoption Consider the information provided on alternatives. Collect additional information about pests, materials and costs from the information sources and suppliers listed for each section. Consider the issues and questions about selecting appropriate alternatives. Annex 4 provides additional guidance. Do you require additional information? Yes Soil uses pre-plant, re-plant, seedlings or nurseries Yes Contact further suppliers and specialists using the address lists Do you require additional information? No

21 2 Guidance for Selecting Non-ODS Techniques A successful and timely transition away from ozone-depleting MB rests upon sound decision-making by many thousands of growers and pest control managers in diverse settings around the globe. In order to control harmful pests successfully without using this traditional fumigant, each user must carefully consider and weigh a complex array of factors unique to his or her situation, ultimately choosing an alternative that fits their particular circumstances. This Sourcebook is a tool for assisting in that effort and provides detailed information and references for individual MB users to draw upon. This Section offers a broad framework for decision-makers to use in selecting and organising information relevant to their own situation. In addition, Annex 4 includes a step-wise guide for evaluation and selection of alternative techniques. Selecting and evaluating alternatives Growers and others trying to identify suitable replacement options for MB must gather a good deal of information - not only about the technical efficacy and requirements of a single, promising approach - but also about other options, costs, secondary impacts and compatibility with overall goals and operations. There are numerous trade-offs that must be considered when evaluating the pest control options. In general, the factors that decision-makers must review can be grouped into seven broad categories: Organisational. Technical. Economic. Regulatory. Health and safety. Market and consumer. Environmental. Applicable to most MB users, these factors are discussed in turn below. It will be difficult for many MB users to envisage life without MB. But the experience of phasing out other ODS which were once seen as essential has highlighted the necessity of thinking outside the square and the importance of leadership by innovative individuals and companies. Organisational considerations Decision-makers in farms and other MB-using enterprises need to consider the relationship between an organisation s phase-out efforts and its other activities and priorities. Competing or conflicting elements must be recognised and reconciled in a fashion appropriate to the organisation in question. Important organisational factors are listed below. Commitment by decision-makers Clearly, an enterprise s phase out of ODS is greatly facilitated when key managers and decision-makers throughout the organisation are fully committed to achieving such a goal. Programmes to build support within an organisation will be an important part of an alternative strategy. Company policies on pest control, environmental issues or other matters Some enterprises may have specific policies on pest management, including policies that favour or even require the use of MB fumigation. They may have corporate policies that 9Section 2: Guidance for Selecting Non-ODS Techniques

22 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 10 address particular residues, air emissions, quantity of waste generation, recycling, or other factors that may be relevant to MB or certain alternatives. An important step is to review existing policies and practices, in order to amend any policies that encourage use of MB, inhibit the adoption of alternatives, or otherwise impede the transition away from MB. It is also desirable to examine relevant policies of the company s suppliers and purchasers. Production methods and schedules Changing the pest control system for an operation normally requires changes in other activities, such as management and daily practices on the farm or enterprise. Some alternatives may require higher levels of skill, and higher or lower labour inputs, for example. Successful adoption of a non-ods alternative may therefore require adjustments to management, the organisation of work, staffing levels, staff selection, and/or training. Early consideration and planning to address these changes will ease the transition to new pest control practices. Availability of resources Access to technical and financial resources may be the factor that has the single greatest impact on the selection of MB alternatives, particularly for small and medium-sized enterprises with limited resources. Often a a company has to re-prioritize its existing resources, and draw on external resources for technical expertise, advice, information or training. The Multilateral Fund of the Montreal Protocol was created to address this problem in developing countries, by providing essential equipment and training for enterprises and farms. Technical considerations The selected alternative must be technically effective in controlling the pest problems in your local climate and circumstances. MB is one of many pest control methods, but few can control the same very wide range of pests that MB controls. In most cases, MB must be replaced by a combination of several techniques which, together, will control the range of pests likely to be encountered. Integrated Pest Management (IPM), is based on pest identification, monitoring, establishment of pest injury levels and a combination of strategies to prevent and manage pest problems in an environmentally sound and cost-effective manner (MBTOC 1998). It offers a useful overall approach for selecting and implementing effective, workable alternatives for a wide range of MB uses. Many specialists around the world recommend this general approach for dealing with pest problems, and IPM is being used on a wide scale in some sectors, generally for controlling pests found on the stems and leaves of crops. Some IPM programmes have been developed for soil-borne pests and stored product pests. The careful tailoring of pest management practices to a specific situation is fundamental to the IPM approach. Each application of IPM involves its own combination of several techniques selected from biological, cultural, physical, mechanical and chemical control methods. Formulating and applying a successful IPM programme, therefore, requires information, analysis, planning, and much more know-how than does the use of MB. Sections 3, 4, 5, and 6 give further information about IPM practices and important technical factors to consider in the evaluation of alternative pest control methods. Economic considerations Operating costs and profitability, like access to capital, are critical factors in the selection of alternatives. Initial costs associated with an MB alternative may include capital costs of equipment, additional costs associated with handling that new equipment, costs of new permits or licenses, and costs of training personnel in new systems and methods. Operating costs may include ongoing costs for materials and supplies, labour, maintenance or servicing of equipment, or energy and transportation costs.

23 In evaluating these points, it will be important to consider the long-term cost package. At first glance some alternatives may appear unreasonably costly because they require a large initial investment in training, equipment, etc. But when costs over the long term are considered, the same alternatives can actually be cost-effective. What s more, an assessment of costs alone does not provide a complete picture. Alternatives which have higher operating costs can be as profitable as MB if they give higher crop yields or raise the market value of products. Likewise, an alternative that results in reduced yields can be as profitable as MB if the costs are sufficiently lower, as found with solarisation for example. So the profitability or net revenue needs to be examined. In future, the price of alternatives will become more favourable when the inputs become widely available and the techniques are optimised. The cost of MB itself will be much less attractive in future because the prices of MB will tend to rise as supplies dwindle. While traditional economic evaluation is very important, it is also necessary to recognise that an MB reduction programme is justified on the basis of environmental protection and the need to reduce externalised costs in agriculture. Finally, the economic analysis could also consider the possibility of accessing funds from the Montreal Protocol s Multilateral Fund. The fund was established to provide financial and technical assistance for ODS users in developing countries who wish to adopt alternative techniques. Funds for MB projects have been made available in the last few years. By the end of 2000 the Multilateral Fund had approved about 100 MB projects, including information materials, workshops and projects to demonstrate alternatives. In 1999 the Fund decided to give priority to projects that will phase out MB in specific sectors, via investment, training and policy development. The national ozone protection offices of governments are normally able to provide information about the procedures for applying for this assistance. Alternatively, the Multilateral Fund Secretariat website provides information. (See Information Resources in Annex 5.) Regulatory considerations Pesticides and fumigants, like MB, normally have to be registered by the government authorities responsible for pesticide safety, so the availability of particular chemicals will vary from country to country or even within different regions of a country. For example, phosphine, an alternative fumigant for stored grains, is registered in many countries, while some other chemical alternatives are registered in only a few countries. Biological controls and soil amendments also require registration in some countries. Prospective users of alternative chemicals will usually find that official approval or registration of a chemical product is accompanied by diverse safety requirements which limit the way a product can be applied. The use of registered pesticides is normally restricted to specific crops and operations; the application rates (doses) may be limited; and there are special conditions on sales, safety equipment, training and disposal of waste chemicals and containers. In many instances, restrictions are set on the levels of pesticide residues that may remain in foods. Some chemical alternatives, such as sulphuryl fluoride, are not permitted for treating food products at present. The process of applying for a new pesticide registration is very expensive, and this task is normally carried out by companies that wish to sell the product in countries where they expect to gain a large market. To find out whether a product is registered for use in your country and for your type of crop or application, it is best to contact the Section 2: Guidance for Selecting Non-ODS Techniques 11

24 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 12 government authority responsible for pesticide safety and registration - often found in the Ministry of Agriculture or Health. Local agricultural product suppliers are normally able to give information on registered products and uses, although their information may not be up-to-date or completely reliable. Under international guidelines, registered products are supposed to carry labels that inform users on approved uses, application rates and safety precautions. On the other hand, many non-chemical alternatives, such as steam, substrates and solarisation, are not subject to registration and, therefore, are accessible immediately to users. In addition to issues related to the registration and use of chemical alternatives, there may be other regulatory issues that affect choices. Local, state or national regulations may govern emissions, wastes generated or other aspects of agriculture for example. Exporters also need to be aware of relevant regulations in the countries to which they export. Health and safety considerations Worker health and safety should be considered in the selection of an MB alternative. MB itself has high acute toxicity, and in a number of countries can be used only by licensed, trained fumigators. Many chemical alternatives require significant safety precautions as well. In contrast, many non-chemical alternatives have little or no toxicity, although a few pose risks of dust or other physical hazards. The following are among the health and safety factors that should be examined as part of the selection process. Toxicity. The potential for problems of acute toxicity resulting from exposure to significant levels of toxic compounds over short periods or chronic toxicity resulting from low dose exposure over longer periods must be carefully considered for any pest control product. As with MB, pest control managers should establish safety management procedures for avoiding worker exposure and keeping within the safety limits set by health agencies. It is also necessary to provide adequate safety training, safety equipment, protective apparel and health monitoring. Flammability. Fire and explosion risks should be evaluated, and preventive measures instituted if required. Dust. Workers must be protected from dusts that can irritate lungs and eyes in the short-term or lead to lung disease over the long term. Suffocation. Certain alternatives, such as controlled atmospheres, have the potential to present suffocation hazards if managed improperly. In considering these alternatives, safety measures and training are required to ensure that workers are not exposed to an environment with insufficient oxygen. Extreme heat or cold. In adopting an MB alternative that employs extreme heat or cold, appropriate measures must be taken to assure that accidental exposures to extreme temperatures do not cause injury to workers. Mechanical hazard. Poorly designed equipment, lack of safety guards on moving parts, or worker unfamiliarity with new equipment can lead to injury. The need for special training, safety equipment or other measures to protect workers must be factored into the selection of MB alternatives. Problems can be avoided by selecting alternatives free from these problems. Where this is not possible, safety management is important. This means having a plan and procedures in place to ensure that safety precautions are

25 introduced, workers are trained and workplace practices are carried out safely. Market and consumer considerations Agricultural products have to be acceptable to purchasers. Visual appearance and commercial grade standards are significant factors, particularly for supermarkets, and alternatives must provide products that meet these standards. Purchasers of agricultural products, from supermarkets to individual consumers, are becoming increasingly concerned about pesticide residues and the environmental impacts of agriculture. Supermarkets in northern Europe are requiring fruit and vegetable producers to introduce IPM and other production methods with reduced environmental impacts. These trends and consumer concerns will affect the long-term market acceptability of chemical alternatives, and of MB itself. Environmental considerations Like MB, certain alternatives pose risks to human health or the environment. In the context of the Montreal Protocol we take a step forward when we replace an ODS with a non-ods. But it also makes sense, from both marketing and environmental perspectives, to select alternatives that do not contribute significantly to other environmental problems. Issues to consider include those listed below. Ozone depletion and global warming. Each alternative must be evaluated for its contribution to global warming and ozone depletion. It would generally be considered undesirable to replace an ozone-depleting chemical like MB with a non-ozone-depleting chemical that has a significant global warming potential. Use of non-renewable sources of energy and materials. Wherever possible, MB should be replaced with alternatives that conserve energy. In some situations it may be feasible to use renewable sources of energy or waste heat from local industries. It can also be feasible to use renewable waste materials as soil amendments or substrates, for example. Air pollution. Many pesticides and other chemicals create fine mists that pollute the local environment and in some cases travel thousands of miles to pollute other regions. Selection of alternatives should seek to avoid or minimise all forms of air pollution. Water contamination (surface and groundwater). Some agricultural practices result in residues and breakdown products that leach into water, impacting plants and animals that live in the ponds, rivers and seas. The vulnerability of water to contamination from everyday operations and/or accidents should be considered. Soil contamination. Some pest control techniques - notably pesticides - leave residues and breakdown products in soil and crop debris, affecting beneficial soil organisms and non-target plants and animals. Although active ingredients may break down quickly, some breakdown products can persist for long periods. Food contamination. Some pesticides can leave undesirable residues and breakdown products in food, creating potential problems for consumers, especially young children, or leading to products being rejected by markets. Increasingly, supermarkets favour pest control methods that avoid the risk of food residues. Solid waste. Waste containers, plastic and other materials can litter the countryside or fill up large areas of landfill sites. Where possible, it is advisable to avoid generating waste, to reduce the Section 2: Guidance for Selecting Non-ODS Techniques 13

26 use of items that create waste, and/or to set up local recycling schemes. Identify the environmental impacts resulting from your operations. Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Habitat and biodiversity. Some agricultural practices reduce the diversity of plants or animals, often by destroying their habitats. Broad-spectrum treatments like MB, fumigants and steam sterilisation destroy much of the biodiversity in the soil. Where possible, it is desirable to use methods which foster local habitat development, wildlife, and organisms that benefit crop production. The following steps can help to avoid or mitigate potential environmental problems: Consider the entire life cycle of inputs, including their extraction, transportation, use and disposal. Where possible, modify practices to avoid or reduce negative impacts. Monitor the efficacy of changes. Carry out regular reviews, so that the enterprise s environmental performance can be continuously improved. 14

27 3 Control of Soil-borne Pests Soil-borne pests can cause substantial crop damage and economic losses. This is particularly true in intensive agriculture where crops are planted in the same place year after year, creating conditions that foster pest populations in the soil. The five main categories of soil-borne pests are as follows: Nematodes. Tiny worm-like creatures that live in the soil, nematodes vary in size from microscopic to about 5 millimetres in length. Some species are agricultural pests, while others are actually advantageous to agriculture. Pest nematodes, generally called plant parasitic nematodes, feed in or on the roots of crops. Root knot nematodes for example, cause large swellings in plant roots. These root galls drain a plant s energy resources and limit the uptake of water and nutrients, thus reducing crop growth and yields (Strand et al 1998). Some nematodes transmit harmful viruses or leave open wounds that allow pathogenic fungi to enter roots. Fungi. Certain soil-dwelling fungi (such as species of Fusarium, Verticillium and Phytophthora) attack plant roots or the base of stems, causing diseases in the plants and reducing crop yields. Bacteria and viruses. A number of soilborne bacteria and viruses are also harmful (pathogenic) and cause diseases in crops. As with nematodes and fungi, the soil contains some beneficial bacteria that help to protect plant health. Soil insects. Certain soil-dwelling insects, such as cutworms and false wireworms, damage plants by eating roots or infecting them with fungi or bacteria. Some of the insects that eat or damage plant leaves and fruit spend certain stages of their lives in the soil, typically as larvae or pupae. Weeds. A range of weeds and weed seeds cause problems by competing with crops for root space, nutrients, water and sunlight. These include annual and perennial broadleaf weeds, grasses and sedges. A few weeds, such as broomrape, are actually parasitic on crops. Though it is capable of controlling many pests (see Table 3.1 through 3.5), MB is often applied to control just one or two groups of pests or used as general insurance against the broad range of soil pest problems. Frequently, farmers who use MB do not know which pests are present in soil. Thus some MB is applied when it is not actually necessary. Though sometimes portrayed as the perfect pest control tool, MB does not control all pests. For example, MB has only limited effect in controlling the disease caused by Phomopsis sclerotioides in cucumber (Gyldenkaerne et al 1997). Likewise, corms and seeds of weeds such as horseweed, mallow and legumes, and many bacteria are not effectively controlled by MB (Klein 1996). There are other disadvantages as well. MB kills many of the soil organisms that benefit agricultural production. It is highly toxic; some forms of application are rather complicated; it may leach into water in some areas; Section 3: Control of Soli-borne Pests 15

28 Table 3.1 Soil-borne nematode pests controlled by MB in various regions of the world Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 16 Pests Africa Mediterranean South America Japan USA Nematodes Aphelenchoides spp. Ditylenchus spp. Globodera spp. Heterodera spp. Longidorus spp. Meloidogyne spp. Nacobbus sp. (seedbeds only) Paratrichodorus spp. Pratylenchus spp. Rotylenchulus spp. Xiphinema spp. Sources: MBTOC 1994, 1998 Table 3.2 Soil-borne fungal pests controlled by MB in various regions of the world Pests Africa Mediterranean South America Japan USA Fungi Alternaria spp. Armillaria spp. Clitocybe spp. Colletotrichum spp. Cylindrocladium spp. Fusarium spp. Glomus spp. Macrophomina spp. Mucor spp. Phoma spp. Phymatotrichum Phytophthora spp. Plasmodiophora spp. Pyrenochaeta spp. Pythium spp. Rhizoctonia spp. Rhizopus spp. Rosellinia spp. Sclerotinia spp. Sclerotium rolfsii Thielayiopsis spp. Verticillium spp. Sources: MBTOC 1994, 1998

29 Table 3.3 Soil-borne bacteria and virus pests controlled by MB in various regions of the world Pests Africa Mediterranean South America Japan USA Bacteria and viruses Agrobacterium spp. Clavibacter spp. Cucumber mosaic Erwinia spp. Grape fanleaf Pseudomonas spp. Streptomyces spp. Tobacco mosaic Tomato spotted wilt Xanthomonas spp. Sources: MBTOC 1994, 1998 Table 3.4 Soil-borne insect pests controlled by MB in various regions of the world Pests Africa Mediterranean South America Japan USA Insects Agrotis spp. (cutworms) Frankliniella occidentalis Lyriomyza trifolii Mole crickets Otiorhynchus spp. Root weevils Symphylans Termites Tetranychus urticae White grubs Wireworms Sources: MBTOC 1994, 1998 Table 3.5 Weeds controlled by MB in various regions of the world Pests Africa Mediterranean South America Japan USA Weeds Cyperus spp. Orobanche spp. Broad leaf (perennial and annual) Grasses Sedges Section 3: Control of Soli-borne Pests Sources: MBTOC 1994,

30 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 18 andbromide residues may accumulate in crops (Katan 1999). MB-based control One of many pest control methods, MB is versatile and effective against a broad spectrum of pests, including weeds. (See Tables 3.1 through 3.5.) It is effective at relatively low temperatures and penetrates soil well, reaching pests in different areas and soil depths. Decades of accumulated experience in some regions of the world have allowed farmers to make optimal use of MB while avoiding situations in which it is not effective or has severe local side effects (Katan 1999). As a result, MB has become highly acceptable and popular with many farmers. Still, around the world many crops are also produced successfully without MB (MBTOC 1998). Overview of alternative pest control techniques The techniques identified by the Methyl Bromide Technical Options Committee (MBTOC) for controlling soil-borne pests (MBTOC 1994, 1998) can be divided into the two broad categories listed below. Each technique is further described in Section 4. Non-chemical methods Cultural practices, such as crop rotation, resistant varieties, grafting, mulching, cover crops, ploughing, tillage, hygienic practices or sanitation, and water management. Biological controls, i.e. beneficial soil organisms that control or suppress pests. Soil amendments and compost. Solarisation. Table 3.6 Range of soil-borne pests controlled by MB and alternative techniques Non-chemical techniques Spectrum of soil pests that can be controlled Nematodes Fungi Weeds Insects Biological controls Crop rotation Grafting Resistant varieties Soil amendments Solarisation Steam Substrates (soil substitutes) Chemical treatments MB Chloropicrin Dazomet 1,3-dichloropropene Metam sodium MITC Nematicides Fungicides Herbicides Key: narrow range of pest species intermediate range wide range

31 Steam heat. Substrates or soil substitutes. Chemical methods Fumigants, such as chloropicrin, dazomet, 1,3-dichloropropene, MITC, metam sodium. Non-fumigant pesticides, primarily nematicides, fungicides and herbicides. While steam treatments control the same broad spectrum of pests as MB, most other techniques control a smaller range of pest species. Table 3.6 illustrates the range or spectrum of soil pests controlled by chemical and non-chemical techniques. Where a narrow range of pests is present, one technique may give sufficient control. However, in situations involving a wide spectrum of pests, it is often necessary to replace MB with a combination of several techniques. So a combination might comprise, for example, a fumigant or solarisation to control certain nematodes, fungi and weeds, plus a second technique to control a problematic nematode species, and a third technique to manage problem weeds. Identifying suitable combinations is the key to developing effective MB alternatives. Table 3.7 provides a comparative overview of the efficacy of different techniques, examples of techniques that are compatible in combination, and information on timing of applications (see also Section 4). Examples of alternatives in commercial use MBTOC has identified a wide variety of cases in which alternative techniques are being used commercially for control of one or more soil-borne pests (MBTOC 1998). Table 3.8 provides a summary of the main techniques known to be in widespread commercial use in some countries. (See Section 4 for additional detail on each technique.) The countries cover diverse climatic regions of the world, including Brazil, Canada, Chile, Colombia, Egypt, Germany, Japan, Jordan, Malawi, Mexico, Morocco, Netherlands, Spain, USA and Zimbabwe. Tables 3.9 through 3.16 provide, for each major crop, examples of countries in which MB alternatives are in commercial use. The tables specify whether such uses is widespread (W) or limited (L). Data is provided for the following crops: Cucurbits- melons, courgettes (zucchini), cucumbers (Table 3.9). Tomatoes and peppers (Table 3.10). Strawberries (Table 3.11). Cut flowers (Table 3.12). Roses (perennials) (Table 3.13). Tobacco seedbeds (Table 3.14). Nurseries (vegetables and fruit) (Table 3.15). Perennial crops, e.g., orchard trees, banana plants (Table 3.16). Uses without alternatives MBTOC noted that there is no single crop that cannot be produced successfully without MB (MBTOC 1998). However, MBTOC identified a limited number of pests and specific situations where it is currently difficult to achieve control without MB, and these include the following (MBTOC 1994, 1998): Certain soil-borne viruses that affect a few specific crop situations. Deep fumigation of almond groves for root rot in the USA. Replant problems in areas where limited land is available. Some certified pest-free propagation materials. MBTOC has estimated that these difficult uses account for less than 5% of the MB Section 3: Control of Soli-borne Pests 19

32 Table 3.7 Overview of efficacy and timing of pest control techniques and examples of appropriate combinations of techniques Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Examples of Timing Techniques Efficacy compatible techniques of treatment Non-chemical techniques Biological Suppression of Solarisation, substrates, cover Before and controls certain species of crops, other cultural practices during crop fungi and nematodes production Crop rotation Leads to decline in certain Fumigants, solarisation, biological Crop cycle of types of pathogens; not controls, resistant varieties, at least 3 years effective against pathogens grafting, other cultural practices with wide host range Grafting and Middle to high against specific Fumigants, solarisation, trap At planting time resistant pathogens, depending on crops, other cultural practices varieties rootstock and conditions Soil Good suppression of fungi and Solarisation, biofumigation, Applied 2 weeks amendments some nemaodes; not effective biological controls, resistant to several months and compost against most weeds and insects varieties, other cultural practices before planting Solarisation Effective against many Fumigants, biofumigation, 4-7 week fungi, nematodes and biological controls, resistant treatment prior weeds, except weeds with varieties, grafting, crop rotation, to planting deeply buried structures other cultural practices Steam Highly effective against many Resistant varieties, grafting, 20-minute to fungi, nematodes and weeds, biological controls, other IPM 8-hour treatment provided treatment is taken methods immediately to sufficient soil depth before planting Substrates Highly effective Biological controls No treatment (soil substitutes) required for clean substrates Chemical treatments MB Highly effective against Biological controls applied after 7-14 days many fungi, nematodes fumigation before planting and weeds Chloropicrin Highly effective against fungi Fumigants, pesticides, resistant At least 14 and some arthropods; varieties, grafting, cultural days before nematicide; weak herbicide practices planting Dazomet Satisfactory against fungi Fumigants, pesticides, days weeds, and certain solarisation, resistant varieties, before planting nematodes grafting, cultural practices 1,3- Effective nematicide, Fumigants, pesticides, resistant 7-45 days dichloropropene suppresses some fungi varieties, grafting, cultural before planting and weeds (limited) practices Metam sodium Highly effective against Fumigants, pesticides, About fungi; effective against solarisation, resistant varieties, days before arthropods; controls grafting, cultural practices planting some weeds and certain nematodes 20 Compiled from: Lung et al 1999, MBTOC 1998

33 Table 3.8 Summary of techniques in widespread use in some countries Techniques Biological controls Crop rotation, fallow Grafting Fumigants other than MB Resistant varieties Solarisation Steam Substrates Crops or uses Tobacco seedlings, citrus trees Cucurbits, strawberries, cut flowers, nursery crops Cucurbits, open field tomatoes and peppers, nursery crops, pip and stone fruit trees, nut trees, perennial vines Cucurbits, open field tomatoes and peppers, strawberries Cucurbits, open field tomatoes and peppers, strawberries, cut flowers Cucurbits, protected tomatoes and peppers, cut flowers, nursery crops Cucurbits, protected tomatoes and peppers, cut flowers, protected nursery crops Cucurbits, protected tomatoes and peppers, tobacco seedlings, strawberries, cut flowers, protected nursery crops, banana plants Compiled from: MBTOC 1998 Table 3.9 Cucurbits: melons, watermelons, courgettes (zucchini), cucumbers: examples of alternatives in commercial use Alternative techniques Countries Resistant varieties Developing countries (W), developed countries (W) Grafting Egypt (L), developed countries (L-W), Jordan (L), Lebanon (L), Morocco (L), Spain (W), Tunisia (L) Solarisation Developed countries (L), Jordan (L-W) Steam Europe (W) Biological controls Brazil (L), Europe (L) Biofumigation Developed countries (L) Substrates Europe (W) Crop rotation Universal (W) Fumigants Costa Rica (L-W), Egypt (L-W), Honduras (L-W), developed countries (L-W), Jordan (L-W), Mexico (L-W), Morocco (L-W), Zimbabwe (L) Key: W - Widespread commercial use L - Limited commercial use used for soil-borne pest control around the world. Strategies for controlling pests Some pest control techniques are primarily curative and applied after a pest has become established in the soil. Others aim to prevent pest populations from building up and thus avoid the need for curative treatments. After a plant has become infected, control of many soil-borne diseases becomes difficult. So, tactics to control diseases must normally be Compiled from: MBTOC 1998, Rodríguez-Kábana 1999 implemented prior to planting. In addition, some form of continued protection during crop production is desirable. Examples of curative treatments include fumigants, fungicides, herbicides and steam treatments. Preventive techniques include hygienic practices, crop rotation (i.e. planting crops in a planned sequence to disrupt pest life cycles), use of substrates with inherent pestsuppressive properties, and application of soil amendments to create an environment antagonistic to specific pests, such as a change in Section 3: Control of Soli-borne Pests 21

34 Table 3.10 Tomatoes and peppers: examples of alternatives in commercial use Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 22 Alternative techniques Countries Protected cultivation Steam Belgium (W), Netherlands (W), UK (L) Solarisation Japan (L), Jordan (W), Morocco (L) Substrates Belgium (W), Canada (L), Denmark (W), Morocco (L), Netherlands (W), Spain (L), UK (L) Fumigants Egypt (L), Europe (L-W), Jordan (L), Lebanon (L), Morocco (L), Tunisia (L) Open field Solarisation Israel (L-W), Japan (L), USA (L) Substrates Canary Islands (L) Crop rotation, fallow Universal (L-W) Resistant varieties Developing countries (W), Japan (W), Spain (W), USA (W) Grafting Japan (W) Fumigants Australia (W), Brazil (W), Costa Rica (W), Egypt (W), Europe (L-W), Japan (L), Jordan (W), Lebanon (W), Mexico (W), Morocco (W), Spain (W), Tunisia (W), USA (L-W), Zimbabwe (W) Key: W - Widespread commercial use L - Limited commercial use Alternative techniques Substrates Organic amendments, composts, etc. Crop rotation, fallow Resistant varieties Fumigants Solarisation Biocontrols Table 3.11 Strawberries (runner and fruit production): examples of alternatives in commercial use soil ph. Some preventive techniques can also be used as curative treatments in certain circumstances. Combining several weaker methods of pest control can give sufficient control of pests. When a pathogen is exposed to a sub-lethal treatment, it is not killed immediately but is damaged and weakened, becoming more Countries Indonesia (L), Malaysia (L), Netherlands (W), UK (L) Universal (W) Universal (W) Denmark (W), Japan (L) Egypt (L), Japan (L), Jordan (L), Lebanon (L), Morocco (L-W), Netherlands (W), Spain (W), Tunisia (L-W), UK (L) Developed countries (L) Japan (L) Key: W - Widespread commercial use L - Limited commercial use Compiled from: MBTOC 1998 Compiled from: MBTOC 1998 vulnerable to other treatments and to control by beneficial microorganisms in the environment (Katan 1999). The approaches for controlling soil-borne pests can be categorised in two broad groups: a) Sterile or near-sterile conditions.

35 Alternative techniques Protected cultivation Steam Solarisation Substrates Organic amendments, composts, etc. Crop rotation, fallow Resistant varieties Open field cultivation Fumigants Organic amendments, composts etc. Crop rotation, fallow Solarisation Resistant varieties Table 3.12 Cut flowers: examples of alternatives in commercial use Countries Colombia (W), Europe (W) Developed countries (L), Lebanon (L-W) Brazil (L), Canada (W), Europe (W) Universal (W) Universal (W) Universal (L-W) Brazil (L), Colombia (L-W), Costa Rica (L), developed countries (L-W), Morocco (L-W), Zimbabwe (L) Universal (W) Universal (W) Developed countries (L) Universal (L-W) Key: W - Widespread commercial use L - Limited commercial use Compiled from: MBTOC 1998 Table 3.13 Roses: examples of alternatives in commercial use Alternative techniques Countries Resistant varieties Universal (L-W) Grafting Universal (L-W) Substrates Belgium (W), Denmark (W), Netherlands (W) Biological controls Morocco (L), USA (L) Fumigants Morocco (L), Spain (L), Tunisia (L), others (L) Steam (protected cultivation) Belgium (W), Netherlands (W) Solarisation Israel (W) Key: W - Widespread commercial use L - Limited commercial use Compiled from: MBTOC 1998 Table 3.14 Tobacco seedlings: examples of alternatives in commercial use Alternative techniques Countries Fumigants Brazil (L-W), Japan (L-W), USA (L-W) Biocontrols (Trichoderma) Malawi (W), Zambia (L), Zimbabwe (W) Biofumigation South Africa (L), USA (L), Zimbabwe (L) Substrates Brazil (L-W), South Africa (L-W), USA (L-W) Key: W - Widespread commercial use L - Limited commercial use Section 3: Control of Soli-borne Pests Compiled from: MBTOC

36 Table 3.15 Nursery crops (vegetables and fruit): examples of alternatives in commercial use Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 24 Alternative techniques Steam Solarisation Biocontrols Substrates (protected cultivation) Soil amendments, composts, etc. Crop rotation, fallow Resistant varieties Grafting Biofumigation Countries For protected cultivation: Many countries (W) For open fields: Denmark (L) Widespread countries (L-W) Canada (L), Germany (L), Israel (L), Mauritius (L), Netherlands (L), Switzerland (L), UK (L) Brazil (W), Canada (W), Chile (W), Denmark (W), Germany (W), Israel (W), Mexico (W), Morocco (W), Netherlands (W), Spain (W), Switzerland (W), UK (W), USA (W), Zimbabwe (W) Widespread countries (W) Widespread countries (W) Widespread countries (L), including Egypt, Jordan, Lebanon, Morocco, Tunisia Widespread countries (W) Brazil (L), Israel (L), Mexico (L), USA (L) Key: W - Widespread commercial use L - Limited commercial use Table 3.16 Perennial crops such as banana, orchard trees, vines (re-plant): examples of alternatives in commercial use Alternative techniques Countries Apple, pear, stone fruit trees Biological controls USA (specific pests, L) Grafting Universal (specific pests, L-W) Fumigants Spain (L-W), USA (L-W) (stone fruit only) Banana plants Soil amendments Universal (L-W) Substrates Canary Islands (W) Fumigants Costa Rica (L-W) Citrus trees Biological controls Florida USA (root weevil, W) Fumigant Florida USA (L), Spain (L) Nut trees Grafting Universal (pest specific, W) Perennial vines Substrates Canary Islands (L) Grafting Universal (pest specific, W) Key: W - Widespread commercial use L - Limited commercial use Compiled from: MBTOC 1998 Compiled from: MBTOC 1998

37 b) Tolerable levels of pests. Sterile conditions: here, the aim of soil treatment is to kill or eliminate most organisms in the soil in order to create a semi-sterile or sterile medium in which to grow seedlings, greenhouse crops or very intensive field crops. MB and other broad-spectrum treatments fall into this category. Other techniques in this category include certain combinations of fumigants and pesticides, inert substrates, steam treatments and solarisation combined with fumigants. A drawback of creating near-sterile conditions is that if pathogens enter the system they can spread rapidly in the absence of natural predators. However, the addition of beneficial soil organisms to the sterile medium after treatment can help to reduce this problem. Tolerable levels of pests: in this approach, key soil pests are reduced to economically acceptable levels in order to obtain a profitable crop. The aim is not to kill all pests but to suppress pest activity and reduce pest numbers to tolerable levels. This approach relies heavily on the identification and monitoring of pests and is often referred to as an IPM approach. Methods used in this approach may include a combination of cultural practices along with mechanical, physical, biological and pest-specific chemical techniques. In practice, IPM approaches and techniques vary greatly from one farm or region to the next. At one end of the spectrum, farmers may focus heavily on preventive methods, working, for example, to create soil conditions that suppress pests. Other IPM users may rely more on curative treatments, such as target-specific chemicals. There are many cases in which a broad spectrum of pest control is not required, because particular pests are absent or below damage thresholds. When deciding which pest control techniques to use, therefore, it is always desirable to first identify the pests present in soil and then to select the combination of techniques appropriate for those particular pests. This identification of pests and selection of targeted control methods is fundamental to the IPM approach. Crops and crop production systems The general techniques available for replacing MB are broadly similar for most crops, as shown by the examples given in Tables 3.9 through Horticultural crops, however, can be classified into groups that tend to have different production problems and needs: Vegetables, such as tomatoes, peppers and courgettes (zucchini). Soft fruit, such as strawberries. Orchard trees and vines. Annual ornamentals. Perennial ornamentals, such as roses. Tobacco. Turf and golf courses. The spectrum of techniques suitable for each crop and variety varies, as does the opportunity to intervene and control soil-borne pests. Different varieties or strains of the same crop can have very different susceptibilities to pests. This means that changing from one variety to another may be part of a transition away from MB. The details of each pest control technique must vary according to the production system: Seedbeds, propagation beds and nurseries generally require a high degree of freedom from pests. This is particularly true for certified propagation materials. Alternatives which provide this level of pest freedom include substrates and efficient steam techniques. Greenhouses tend to need a high degree of pest control. Section 3: Control of Soli-borne Pests 25

38 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 26 Open field crops tend to tolerate slightly lower levels of pest control, except in very intensive systems. The needs of re-planted crops vary greatly from site to site. Alternatives therefore need to be selected and adapted to suit the specific crop system, and to fit the timing of crop production cycles. For example, if two or more crops are produced each season, a grower must either use a technique that fits with the double- or multi-cropping pattern, or alter the cropping pattern to accommodate a new approach. Likewise, for growers who aim to meet particular market windows, it is important to find techniques which enable the harvest to be ready when market prices are high. Identifying suitable alternatives As noted earlier, MB is effective against a broad range of pests. In making a transition away from this fumigant, therefore, many MB users will find that while a variety of alternative control methods are available, simple substitution is generally not possible. As explained above, a mix of alternatives will often be required. The selection of appropriate combinations of alternatives is inherently more complicated than the traditional use of MB, but the selection process can be simplified and made manageable by organising information and following a step-wise decision-making process. The key to identifying an alternative for a specific field or greenhouse is to start by listing the soil-borne pests of the crop or area, and then list the alternative methods that could be used to control each pest. Working from a list of techniques effective for the specific pests, it is possible to identify combinations of techniques that would be effective for the precise range of pests. The next stage involves gathering information about the profitability, advantages and drawbacks of the main combinations. Only with this sort of information in hand is it possible to select the most appropriate approach for a given situation. For guidance in using this selection approach along with the information in this Sourcebook, consider the steps listed below and review the templates for decision-making provided in Annex Identify problem pests at your site. In addition to current pests, list the pest problems that existed prior to any use of MB. 2. Determine the level of control required. 3. For each pest you have listed, write down the control methods that would be technically effective.table E in Annex 4 provides a template: list your key pests in column 1, and list effective controls in column Use the lists prepared for each pest to identify combinations of techniques that would control your full list of pests. (Annex 4: Table E, column 3). Once you have identified combinations that would be technically effective in controlling all relevant pests, the next stage is to identify and evaluate the advantages, disadvantages, profitability and suitability of these combinations for your situation. The following steps are suggested: 5. List the technical advantages and disadvantages of each alternative combination identified in the previous stage. 6. Consider the following issues for each alternative combination in turn (refer to Section 2): Organisational. Health and safety.

39 Regulatory present and future. Market and consumer, including acceptability to purchasers, market requirements and opportunities.. Environmental. 7. Find the following information: Sources of materials and expertise. Short and long-term costs, including capital costs, operating costs, yields, profitability and pay-back period. Ways in which costs could be reduced. Ways in which the system could be improved. Steps or changes that would make adoption possible. Annex 4 contains templates for all these steps, while Annex 5 lists many useful sources of information. Contact addresses, listed alphabetically, are provided in Annex 6. Section 3: Control of Soli-borne Pests 27

40 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 28

41 4 Alternative Techniques for Controlling Soil-borne Pests 4.1 IPM and cultural practices Importance of IPM and combined techniques As discussed in Section 3, few alternatives control the wide range of soil pests controlled by MB, and MB replacement normally requires a combination of several practices to achieve a similar level of control. An IPM approach which identifies the problem pests and uses several targeted control techniques, is therefore important in replacing MB. Increasingly recommended as a modern means of controlling pests, IPM has been defined in many different ways. MBTOC describes it as a system based on pest monitoring techniques, establishment of pest injury levels and a combination of strategies and tactics to prevent or manage pest problems in an environmentally sound and costeffective manner (MBTOC 1998). Treatment programmes are site-specific and combine two or more techniques selected from biological, cultural, physical, mechanical and chemical methods. This sub-section provides a brief introduction to the principles of IPM and the major types of cultural practices that can be utilized for pest control as part of an IPM approach. Additional sub-sections discuss the many control techniques that fall under the remaining categories of biological, physical, mechanical and chemical methods. As is emphasized throughout the Sourcebook, virtually all of these options are best used as part of a wellthought out, comprehensive IPM approach. Components of IPM Typical components or steps in an IPM programme may include: Identification of soil pests and possible beneficial soil organisms. A determination of the level of pests that can be tolerated before treatment is used. This threshold level is based on the amount of economic damage that can be tolerated, the size of the populations of pests and beneficial organisms, the time in the growing season, and the life stage of key organisms and their hosts. Regular monitoring and record-keeping on the types and levels of pests and beneficial organisms. A system of practices to prevent pests from building up or spreading, such as cleaning and hygienic practices in greenhouses, and removal of diseased crop residues. Application of treatments, as necessary, to control specific target pests, selecting treatments that avoid or minimise health risks to humans, the environment and beneficial organisms. Evaluation of the results of practices and improvements in the system as necessary. In IPM programmes, treatments should not be applied according to a calendar schedule. Instead, they are applied only when monitoring indicates that the pest will cause unacceptable damage. Treatments are restricted to the particular area or spot where pest problems occur. Section 4: Alternative Techniques for Controlling Soil-borne Pests 29

42 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide IPM approaches are knowledge-based, because they require growers and their advisers to recognise key pests and beneficials and to know about effective techniques of prevention and target-specific control. The development and establishment of IPM systems therefore requires significant effort for local adaptation and the training of technicians and growers. IPM systems are used commercially by at least some growers in many countries. Table provides examples of crops for which IPM is used to control soil-borne pests. Table Examples of crops for which IPM systems are used commercially Crops Containerised conifer nurseries Fresh market tomatoes Cut flowers Flower bulbs Strawberries Vegetables Tomatoes, peppers Countries Canada Northern Florida Colombia Australia Germany Netherlands Spain Source: MBTOC 1998, Ketzis 1992 Cultural practices In general, the most reliable way to deal with pest problems is to anticipate and avoid them (Strand et al 1998), and a wide variety of standard cultural practices can be used for this purpose. Selection of fields, sequence of crops, soil preparation, planting method, timing of planting, choice of variety, fertiliser application and water management can all be manipulated to minimise the chances of pest damage (Strand et al 1998). None of these techniques on their own can replace MB, but all can contribute to IPM systems. Cultural and preventive practices for managing fungal diseases, for example, include the use of disease-free seeds and resistant varieties, cleaning of tools after use to avoid spreading pathogens, and removal of dead and diseased crop debris. Table provides a brief overview of the timing and effectiveness of several cultural practices for controlling pests. All of these are discussed in more detail below. Boxes through give other examples of preventive practices that assist in the management of nematodes, diseases and weeds. Hygienic practices Good standards of hygiene and cleanliness are fundamental to avoiding or reducing the need for curative treatments such as MB. Such practices prevent pests from entering or spreading within the cropping system by removing sources of pests and preventing new pathogen inoculum from entering fields and greenhouses. Many seedling pests, for example, can be controlled by preventive hygienic practices such as those listed below: Cleaning tools, equipment and greenhouses thoroughly after use. Removing infected plant residues from the previous crop. Ensuring that contaminated soil or equipment is not brought into the system or transferred from one greenhouse or production area to another. Restricting access to greenhouses, seedbeds and other areas, to prevent visitors and non-essential personnel from transferring pathogens on footwear or clothing. Using pathogen-free transplants, seeds and bulbs to avoid introducing new pathogens into the soil. Ensuring that irrigation water is free from pathogens and, if necessary, using gravel-bed filters or other methods to clean water before irrigation. 30

43 Table Efficacy and timing of various cultural practices Techniques Efficacy Timing of treatment Crop rotation Can be high, depends on the pathogen. Cycles cover a minimum of Not effective against pathogens with 3 years wide host range. Cover crops and Low for fungal pathogens; trap crops Can be grown with crop, living mulches are highly effective against some or for 2-3 months in nematodes; possible control of weeds off season Nutrient management Middle effect; necessary for good crop Before and during crop management, promoting tolerance to production pathogens Resistant cultivars Middle to high for very specific pests, No waiting period before and grafting depending on rootstock and conditions planting Trap crops and Effective against certain fungi and Can be grown with crop, enemy plants nematodes or for 2-3 months in off season Water management Low to middle efficacy, depends on soil Before and during crop type and pests production Compiled from: Lung et al 1999 Box Examples of preventive practices for soil-borne pests: nematode management Establish local certification schemes to prevent the importation of nematodes on planting materials. Before use, check manure and other materials that may harbour nematodes. Avoid the introduction or spread of nematodes in irrigation water. Clean equipment and tools before moving them. Monitor nematode populations and estimate future populations. Examine the possible use of other high-value crops for rotation. Where available, use resistant varieties or grafted rootstock. Remove weeds that are hosts to nematodes or act as reservoirs of infection. Compiled from: Department of Nematology University of California website, Peet 1995, Strand et al 1998 In a number of cases disease-free planting materials are commercially available; some of these are certified and regulated. Table provides a few examples of companies that supply certified disease-free planting materials. To identify suppliers of certified diseasefree planting materials, contact the relevant government department (normally the Ministry or Department of Agriculture) for information about approved suppliers. Crop rotation Rotation involves planting a succession of different crops, each selected for its ability to withstand or suppress pests that are likely to have built up during the previous crop s growing season. Pathogens that attack only a few crop species can be controlled by rotation, but rotation is not suitable for pathogens that remain in soil for a long time or affect a wide range of crops. Rotation is an ancient and reliable method, but rotations Section 4: Alternative Techniques for Controlling Soil-borne Pests 31

44 Box Examples of preventive practices for soil-borne pests: disease management Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 32 Use disease-free seeds or planting material. Avoid old or poor quality seeds. Where available, use resistant varieties or grafted plants with resistant rootstock. Select planting sites so that susceptible crops are not planted in heavily infested fields. Use transplants where feasible, because damping-off fungi rarely attack established seedlings. Clean tools and equipment after use to avoid spreading pathogenic organisms. Clean footware before entering greenhouses and seedbed areas. Remove diseased crop residues. Rotate to non-host crops where feasible. (Various guides are available for choosing rotations of vegetables according to disease problems, e.g. Peet 1995.) Be aware of the impact of organic matter. Soils high in organic matter may have higher populations of damping-off fungi, but they can also increase the activity of beneficial microorganisms that suppress pathogenic fungi. Manage water and drainage to keep soil around roots from becoming waterlogged, because root rots and damping-off occur in areas with poor drainage. Avoid practices that encourage damping-off, including deep planting, planting into cold, wet or poorly prepared soil and inadequate soil nutrition. Balance watering and fertiliser applications carefully, because excess water and nitrogen encourage certain pathogens. Avoid under-nutrition, because stressed plants that are low in potassium and calcium are more vulnerable to diseases. Avoid too much fertiliser, because the salts may damage roots, opening the way for secondary infections by opportunistic pathogens. Control virus-transmitting insects very early in the season, using oils, soaps and baits, for example. Remove and destroy weeds that transmit viruses, such as solanaceous weeds. Compiled from: Department of Nematology University of California website; Peet 1995; Strand et al 1998 Box Examples of preventive practices for soil-borne pests: weed management Identify weed species and map their location and populations in each field. Update the weed map two to three times each year. Note features such as wet areas, well-drained areas, ph and field borders that may increase or inhibit weed growth. Determine the critical weed-free period, that is, the length of time during which the crop should be practically weed-free to avoid reductions in yield or quality. Make sure that crop seed and mulches do not contain weed seeds. Mow around the field borders to remove sources of weed seeds. Prevent weeds from producing seeds by removing them before seeds develop, for example. Band fertilisers five to ten centimetres from the plants, rather than broadcasting. Rotate crops where feasible. Compost any manure before use to reduce weed seeds. Compiled from: Department of Nematology University of California website, Peet 1995.

45 have traditionally included lower value crops that do not suit MB users. New rotations involving only high-value crops are now being developed. For example, a three-year rotation including melon, hot pepper, peas, cucumber, tomato and squash is used with metam sodium as part of an IPM system in Morocco (Besri 1997). Resistant varieties and grafting Some varieties are resistant to specific pests, and resistant varieties are widely used in Spain, Portugal, Greece, Morocco, France, Israel, Italy and Colombia to help substitute for soil fumigation (MBTOC 1998). The range of resistant varieties is limited to specific pests. In some varieties the resistance can break down under certain conditions, such as high soil temperatures or saline water. Target pests must be identified before the appropriate resistant or partly resistant cultivar can be selected. Table lists examples of companies that supply resistant varieties. Grafting plants onto resistant rootstock has traditionally been used for fruit trees, citrus trees and grape vines, but is now being used for annual crops such as tomatoes, cucumber and melon. This practice is increasingly popular in countries such as Morocco, Tunisia, Lebanon, Egypt, Jordan and Cyprus. The watermelon crop in Almería (Spain), for example, is raised from grafted plants, eliminating use of MB (Tello 1998). In some regions of China, cucumber and watermelon are grafted onto Cucurbita moschata rootstock because it is resistant to Fusarium oxysporium f.sp. cucumerinum (Tang 1999). Grafting can be done mechanically by nurseries or specialised farms. It can also be done by small farmers using simple equipment such as clean, sharp blades, sticky tape and small tubes or clips to stabilise the joined stems (Lung 1999). Table lists examples of companies who supply grafted plants and rootstock for grafting. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Mulches and cover crops Mulches are materials that cover the soil, helping to suppress weeds and certain other pests. For example, opaque black plastic or a thick layer of waste material can exclude or reduce the light that triggers weed seed germination. The use of cover crops to smother weeds is a long-established and widely used cultural practice that can also contribute to the management of diseases and nematodes (Peet 1995). Cover crops must be correctly selected and managed to compete with weeds for resources, and preferably to possess chemical or allelopathic properties that reduce weed growth. Certain grasses have been used to suppress Sclerotinia sclerotiorum, for example (Ferraz et al 1996). Living mulches composed of miniature brassicas or clovers grown with the main crop can also suppress weeds and reduce insect pests without reducing yields in some cropping systems (Thurston et al 1994). Nutrient management Manipulation of plant nutrition and fertilisation can reduce or suppress some soil-borne pathogens and nematodes by stimulating antagonistic microorganisms, increasing resistance of host plants, and/or other mechanisms (Cook and Baker 1983). Time of planting Selection of a planting time that coincides with environmental conditions unfavourable to pest activity can reduce problems with some diseases (Heald 1987, Trivedi and Barker 1986). For example, relatively high temperatures do not favour Verticillium spp., while relatively low temperatures do not favour Fusarium spp. Selecting the appropriate planting time can also help to control root-knot nematodes in some regions (Bello 1998). Trap crops Some plants kill or suppress specific pests. Tagetes, a type of marigold, for example, suppresses specific nematode species, and can be Section 4: Alternative Techniques for Controlling Soil-borne Pests 33

46 Table Examples of suppliers of resistant varieties, rootstocks for grafting and disease-free planting materials Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Plant materials Grafted plants Tomato and cucurbits resistant varieties, resistant rootstock for grafting Flowers resistant varieties Disease-free planting materials Specialists, advisory services and consultants in the use of resistant varieties and/or grafting Examples of companies Grow Group International Nursery SARL, Morocco Hishtil Ashkelon Nursery Ltd, Israel Vivaio Leopardi, Italy De Ruiter Seeds, Netherlands INRA, France Novartis Seeds, Netherlands Rijk-Zwaan, Netherlands Sluis & Groot, Netherlands SPIROU Co, Greece Tézier, France American Rose Society, USA High Country Roses, USA Hortica Inc, Canada Jackson & Perkins, USA P Kooij & Zonen, Netherlands Santamaria, Colombia and Italy SB Talee, Colombia Selecta Klemm, Colombia, Germany and Israel Suata Plants SA, Chile, Colombia, Ecuador and Mexico Yoder Brothers, USA Aplicaciones Bioquímicas SL, Spain Empresa Colombiana de Biotecnología, Colombia Hishtil Ashkelon Nursery Ltd, Israel Propagar Plantas SA, Colombia Rancho Tissue Technologies, USA CCMA, CSIC, Madrid, Spain GTZ IPM project, Egypt GTZ IPM project, Morocco HortiTecnia, Colombia P Kooij & Zonen, Netherlands Santamaria, Italy Selecta Klemm, Germany Statewide IPM Project, University of California, USA Suata Plants, Chile, Colombia, Ecuador and Mexico Van Staaveren BV, Netherlands and Colombia Dr M Besri, Institut Agronomique et Vétérinaire Hassan II, Morocco Dr Ron Cohen, Dept of Vegetable Crops, Ramat Yishay, Israel Dr M Eddauodi, Institut National de la Recherche Agronomique, Morocco Dr Gerhard Lung, University of Hohenheim, Germany Dr E Paplomatas, Benaki Phytopathological Institute, Athens, Greece Dr Gerson Reis, Estaçao Agronomica Nacional, Oeiras, Portugal Dr J Tello, University of Almería, Spain Dr D Vakalounakis, Plant Protection Institute, Heraklion, Greece Prof Tang Wenhau, China Agricultural University, Beijing, China 34 Note: Contact information for these companies are provided in Annex 6.

47 useful if combined with other techniques. Tagetes patula decreases the populations of Pratylenchus spp., Meloidogyne arenaria, Meloidogyne hapla and Meloidogyne javanica, but it does not suppress Meloidogyne incognita. (See Lung 1997 for a comparison of the efficacy of four species of Tagetes against 14 different species of nematodes.) In Morocco, Tagetes patula and Tagetes erecta have given good results when planted as green manure after tomato harvesting and then incorporated into the soil after 6 to 8 weeks (Kaack 1999). The efficacy of trap crops varies according to the method and timing of application. Water management Excessive water creates conditions that favour infection by some soil-borne fungi, such as Phytophthora root rot and damping-off diseases in tomato or root and crown diseases in strawberry (Strand 1994, Strand et al 1998). Too little water, on the other hand, stresses plants and may also make them more vulnerable to attack. Proper water management contributes to disease control in vegetables in southeastern Spain and USA (MBTOC 1998). In areas where excess water is available at appropriate times of the year, temporary flooding or flooding alternated with dry soil can be used to suppress insects or weeds. Specialists and information resources Table provides a list of specialists and consultants in preventive methods and integrated management of soil-borne pests. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Section 4: Alternative Techniques for Controlling Soil-borne Pests 35

48 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 36 Table Examples of specialists and consultants in preventive methods and integrated management of soil-borne pests Admagro Ltda, Colombia Africa Program, Asian Vegetable Research and Development Centre, Tanzania Agrindex Consulting and Project, Israel Agriphyto, Perpignan, France Aplicaciones Bioquímicas SL, Spain Asistec, Ecuador Asociación Colombiana de Exortadores de Flores (ASOCOLFLORES), Colombia Biocaribe SA, Colombia BPO Research Station for Nursery Stock, Netherlands CCMA, CSIC, Madrid, Spain Cenibanano Banana Research Center, Colombia CIAA Agricultural Research and Consultancy Center, Colombia Danish Institute of Agricultural Sciences, Denmark Department of Nematology, University of California, Davis, USA DLV Horticultural Advisory Service, Netherlands Empresa Colombiana de Biotecnología, Colombia Escuela Agricola Panamericana, Honduras FHIA Foundation for Agricultural Research, Honduras FPO Fruit Research Centre, Netherlands FUSADES Foundation for Economic and Social Development, El Salvador GTZ IPM projects, Argentina, Benin, Costa Rica, Egypt, Fiji, Jordan, Kenya, Madagascar, Malawi, Morocco, Panama, Tanzania Indian Agricultural Research Institute, India International Institute for Biological Control, Malaysia Jordanian-GTZ IPM programme, Jordan PBG Research Station for Floriculture and Glasshouse Vegetables, Netherlands Spectrum Technologies Inc, USA Statewide IPM Project, University of California, USA Sustainable Agriculture Research and Education Program, University of California, USA University of Bonn, Germany Vegetable Research and Information Center, University of California, USA Dr Miguel Altieri, University of California, USA Dr Antonio Bello and colleagues, CCMA, CSIC, Madrid, Spain Prof Mohamed Besri, Institut Agronomique et Vétérinaire Hassan II, Rabat, Morocco Dr Robert Bugg and Dr Chuck Ingels, SAREP, University of California, USA (cover crops and cultural practices) Dr G Cartia, Universita di Reggio Calabria, Italy Mr Dermot Cassidy, Geest, South Africa Dr V Cebolla, Instituto Valenciano de Investigaciones Agrarias, Spain Dr Dan Chellemi, USDA-ARS, USA Dr Angelo Correnti, ENEA Departimento Innovazione, Italy Dr FV Dunkel, Montana State University, USA Dr Mohamed Eddauodi, Institut National de la Recherche Agronomique, Morocco (nematode control) Dr Clyde Elmore, Vegetable Crops Department, University of California, USA continued

49 Table continued Dr J Fresno, INIA, Spain (IPM for vineyards) Dr Walid Abu Gharbieh, University of Jordan, Jordan Dr A López García, FECOM, Spain (IPM for cut flowers) Dr Roberto García Espinosa, Colegio de Postgraduados en Ciencias Agricolas IFÍT, Mexico Dr Raquel Ghini, EMBRAPA/CNPMA, Brazil Mr Zoraida Gutierrez, Cultivos Miramonte, Colombia Dr Thaís Tostes Graziano, Instituto Agronomico de Campinas, Brazil Prof M Lodovica Gullino, University of Turin, Italy Dr Saad Hafez, University of Idaho, USA Dr Tim Herman, Crop and Food Research, New Zealand Dr Seizo Horiuchi, National Research Institute of Vegetables, Ornamental Plants & Tea, MAFF, Japan Prof Jaacov Katan, Hebrew University, Israel Dr Nancy Kokalis-Burelle, Horticultural Research Laboratory, USDA-ARS, USA Dr Jürgen Kroschel, University of Kassel, Germany (parasitic weeds) Dr Alfredo Lacasa, CIDA, Spain Dr Leonardo de León, Dirección General de Servicios Agrícolas, Uruguay Dr Gerhard Lung, University of Hohenheim, Germany Dr Nahum Marbán Mendoza, Universidad Autónoma de Chapingo, Mexico Ing Juan Carlos Magunacelaya, Chile Dr Nicholas Martin, Crop and Food Research, New Zealand Dr Mark Mazzola, Tree Fruit Research Laboratory, USDA-ARS, USA (fruit trees) Prof Keigo Minami, ESALQ, University of São Paulo, Brazil Ing Camilla Montecinos, Centro de Educacion y Tecnologia, Santiago, Chile (vegetables) Dr Peter Ooi, FAO Integrated Pest Control Intercountry Programme, Philippines Ms Marta Pizano, HortiTecnia, Colombia (cut flowers) Dr Ian Porter, Agriculture Victoria, Australia Dr William Quarles, Bio-Integral Resource Center, USA Dr Gerson Reis, Estaçao Agronomica Nacional, Portugal Dr Rodrigo Rodríguez-Kábana and Dr Joseph Kloepper, Department of Plant Paghology, Auburn University, USA Dr F Romero, Centro de Investigación Las Torres, Spain Dr Yitzhak Spiegel, Agricultural University, Israel Dr James Stapleton, Kearney Agricultural Center, Univerisity of California, USA Dr Donald Sumner, Dept Plant Pathology, University of Georgia, USA Dr J Tello, University of Almería, Spain Prof Franco Tognoni, Dipartemento di Biologia delle Plante Agrarie, Italy Dr Anne Turner, Agricultural consultant, Zimbabwe Mr Peter Wilkinson, Xylocopa, Zimbabwe Dr Peter Workman, Crop and Food Research, New Zealand Note: Contact information for these specialists and consultants is provided in Annex 6. Please refer also to the specialists listed in Sections 4.2 through 4.7. Additional specialists can be identified in resources such as the National IPM Network ( the Agriculture Network Information Center ( and the OzonAction Programme s Inventory of Technical and Institutional Resources for Promoting Methyl Bromide Alternatives ( Section 4: Alternative Techniques for Controlling Soil-borne Pests 37

50 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Biological controls Advantages Generally safe for non-target species and not toxic to humans. Improve soil biodiversity. Some biological controls promote plant growth. Do not produce undesirable residues in food. Can lead to antagonistic activity in the soil for long periods. Disadvantages Target specific pests, so must be combined with other techniques. Not compatible with conventional pesticides, since pesticides kill or inactivate the organisms. Must be applied regularly in order to establish populations of biological organisms in the soil. Normally require a certain range of ph, temperature and moisture to be active. Often need to be registered as pesticide products, which may initially delay their availability. Technical description Biological control involves the use of living organisms, such as fungi, bacteria or beneficial nematodes, to control or inhibit pest populations. Biological control agents can act against pests in diverse ways, including those listed below: Eating or feeding on pests. Parasitising or living in pests. Repelling pests. Competing with pests for space and nutrients. Establishing a kind of biological shield around crop roots and protecting them against infection. Inducing systemic resistance in crops, i.e., improving the plants own defense systems, enabling them to resist pest attacks more effectively. Stimulating crop growth. Biological controls are normally highly specific, which means that each organism or agent acts against a narrow range of pests typically between one and a dozen pest species (Table 4.2.2). Generally, biological controls cannot, of themselves, replace MB. Rather they must be used as part of an IPM system that includes other practices, such as resistant cultivars, soil amendments, solarisation or alternative pesticide products. Biological controls are effective only when present in sufficient numbers in the root zone, so success depends on selecting the appropriate method of delivery, establishing an environment in which the organisms can thrive, or re-applying the organisms at regular intervals. They are often most effective when applied as seed dressings and root dips or applied to the soil regularly via irrigation pipes. Biological control products are made commercially or, in some cases, on-farm. Commercially produced biological controls can be categorized as follows: Fungi or bacteria Fungi or bacteria are primarily soil-dwelling organisms that prey upon or out-compete some of the pathogenic fungi that attack plants. Examples of commercial products include the following: Beauveria spp. a fungus (commercial products in Colombia and Switzerland). Fusarium oxysporum (nonpathogenic) a fungus (commercial product in France, Hungary, Italy).

51 Table Examples of commercial use of biological controls (normally combined with other techniques) Crop Biological control agents Country Various crops Streptomyces lydicus USA Various crops Streptomyces griseoviridis strain K61 USA Sweet potato Non-pathogenic Fusarium spp. Japan Various crops PGPR bacteria China, Germany, USA Cut flowers Paecilomyces lilacinus, Trichoderma spp., Colombia, Germany, Beauveria bassiana, Bacillus popilliae, Netherlands Metarhizium anisopliae, microbial broths Greenhouse tomatoes Trichoderma applied regularly in New Zealand irrigation water Greenhouse tomatoes PGPR bacteria (seed coating) Germany and cucumber Turf Beauveria bassiana, Metarhizium anisopliae, Germany, Switzerland PGPR bacteria (seed coating) Compiled from: MBTOC 1998, Cherim 1998, Gutierrez 1997, Lung 1999 Gliocladium virens a fungus (commercial products in USA). Paecilomyces lilacinus a fungus (commerical products in Colombia). Pseudomonas spp. beneficial bacteria (commercial products in China, Germany, USA). Trichoderma spp. various species of fungi (commercial products in China, UK, USA, Zimbabwe and many other countries). Nematodes Nematodes are soil-dwelling animals that look like microscopic worms. Some predatory nematodes prey upon root-knot nematodes while other types of nematodes act as parasites and destroy the larve and pupae of insects (Table 4.2.3). Examples of commercial products include: Heterorhabditis bacteriophora beneficial nematode (commercial products in USA). Mononchus sp. beneficial nematode (commercial product in USA). Phasmarhabditis hermaphrodita beneficial nematode (commercial product in UK). Steinernema spp. beneficial nematode (commercial products in USA). Biological controls come in a wide variety of formulations such as wettable powders, granules, pellets and suspensions. They can be applied as top dressings, sprays, drenches, seed coatings or root-dips prior to planting. They can also be applied via sprinklers, drip lines and injection equipment, or can be mixed with substrates (potting mixes or growth media) prior to filling nursery trays or bags. Seed coatings and root dips are effective methods of application, because they allow the beneficial organisms to become established in the root zone from the earliest stages. Depending on the pest pressure and situation, it may be necessary to create a soil environment that fosters the biological control agent and provides appropriate nutrients for it, or it may be necessary to re-inoculate the soil with the organisms at regular intervals. An effective way to ensure that organisms remain present during the entire growing season is to apply them regularly through the irrigation pipes (using special valves that will not become blocked). Section 4: Alternative Techniques for Controlling Soil-borne Pests 39

52 Table Examples of biological control agents and formulations for soil-borne diseases Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 40 Biological Type of Soil-borne control agent organism pests and diseases Formulations Agrobacterium Bacteria Crown gall disease caused by Culture or suspension, applied radiobacter Agrobacterium tumefaciens to seeds, seedlings and cuttings, or as soil drench or spray Ampelomyces Fungi Powdery mildew, Oidium spp. Water-dispersible granules quisqualis isolate for spray Bacillus subtilis Bacteria Rhizoctonia solani, Fusarium Granule or powder, for seed spp., Alternaria spp., Sclerotinia treatment, dip, hopper box, spp., Verticillium spp., Strepto- soil drench or spray myces scabies, Aspergillus spp. that attack roots Burkholderia Bacteria Rhizoctonia spp., Pythium spp., Powder and aqueous suspension cepacia Fusarium spp. and others for seed treatment or drip irrigation Candida Fungi Botrytis spp. Wettable powder oleophila Coniothyrium Fungi Sclerotinia sclerotiorum, Water dispersible granule minitans Sclerotinia minor for spray Fusarium Fungi Fusarium oxysporum, Fusarium Dust and alginate granule oxysporum moniliforme for seed treatment or soil incorporation etc. non-pathogenic Gliocladium Fungi Damping-off and root rot Granules, liquid virens pathogens especially Rhizoctonia solani and Pythium spp. Gliocladium Fungi Pythium spp., Rhizoctonia solani, Wettable powder, liquid catenulatum Botrytis spp., Didymella spp Phlebia Fungi Heterobasidium annosum Powder gigantea Pseudomonas Bacteria Rhizoctonia solani, Wettable powder or suspension cepacia Fusarium spp., for spray Pythium sp. Pythium Fungi Pythium ultimum Granule and powder for seed oli-gandrum treatment or soil incorporation Streptomyces Bacteria Fusarium spp., Alternaria brassi- Powder for drench, spray or griseoviridis cola, Phomopsis spp., Botrytis irrigation system spp., Pythium spp., Phytophthora spp. that cause seed, root and stem rot and wilt disease Trichoderma Fungi Sclerotinia spp., Phytophthora Granules, wettable powder for harzanium, spp., Rhizoctonia solani, Pythium seed treatments, dips, soil incor- Trichoderma spp., Fusarium spp., Verticillium poration, injection, or irrigation polysporum and spp., Sclerotium rolfsii systems other Trichoderma species Compiled from: Fravel 1999, Lung 1999

53 Table Characteristics of several groups of biological controls Group of organisms Examples of organisms Type of organism Target pests Mode of action Gliocladium Gliocladium virens Soil fungi Damping-off diseases, Parasitises some organ particularly those isms (e.g., R. solani) and caused by Pythium and suppress-es by compet- Rhizoctonia; seed rot ition, exclusion and diseases excretion of substances Mycorrhizae Glomus brasilianum, Soil fungi Promote root health, Form symbiotic relation- Glomus clarum, increase plant s ability ship with crop roots, Gigaspora margarita to resist some diseases aiding uptake of water and nutrients especially Nematodes: Heterorhabditis Parasitic Larvae and pupae of Enter insect larvae and Heterohabditis, bacteriophora, nematodes insects; certain cutworm snails/slugs as parasites; Phasmarhabditis Phasmarhabditis species; snails and slugs their metabolites kill & Steinernema hermaphrodita, these organisms Steinernema carpocapsae Nematodes: Mononchus Predatory Root-knot Prey on root-knot Mononchus aquaticus Coetzee nematodes nematodes nematodes Plant growth- Rhizobacteria spp. Bacteria Certain pests and Create a biological shield promoting living in pathogens around roots, preventing Rhizobacteria roots or delaying invasion of pest or pathogen; promote plant growth Steptomyces Streptomyces Soil-dwelling Certain pathogenic Out-compete several lydicus, bacteria fungi pathogens; some create Streptomyces protective mycelia layer griseoviridis around roots or excrete metabolites that inhibit fungi Trichoderma. Trichoderma Fungi Certain pathogenic Create a biological shield harzianum, fungi, e.g., Pythium, around roots, promoting Trichoderma Rhizoctonia Fusarium plant growth and polysporum, preventing growth of Trichoderma viride pathogenic fungi Compiled from: MBTOC 1998, Cherim 1998, Lung 1999, commercial product information Users need to be knowledgeable about appropriate conditions. As living organisms, most biological control agents are active within a certain range of temperatures and soil conditions. For example, Trichoderma needs a soil temperature of at least 10 C and a soil ph that is neutral to slightly acidic. The beneficial nematode Steinernema needs slightly moist soil and temperatures of 4.5 to 32 C, with optimum temperatures of 15.5 to 21 C. Normally biocontrols will be killed or deactivated by pesticides. A notable exception, however, is the bacteria Pseudomonas, which has tolerance against some fungicides. In general biological controls are best suited for use with non-chemical techniques such as grafting, substrates or solarisation. Section 4: Alternative Techniques for Controlling Soil-borne Pests 41

54 Table Examples of nematode pests controlled or suppressed by biological controls Nematode pests Biological control agents Efficacy comments Meloidogyne spp. Paecilomyces lilacinus Slow effect; best results in Pasteuria penetrans 2nd or 3rd years Meloidogyne incognita Mononchus aquaticus Pratylenchus spp. Paecilomyces lilacinus Parasitises eggs of nematodes Various nematode species Myrothecium verrucaria Effective nematicide Pleurotus ostreatus Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 42 Compiled from: MBTOC 1998, Cherim 1998, Gutierrez 1997, Kwok 1992, Lung 1999, Warrior 1996, commercial product information Current uses Biological controls are used commercially in a number of countries, normally as one part of a comprehensive IPM or non-chemical system. Table provides examples of biological control agents in commercial use. Variations under development Additional species with pest control effects are being identified. Studies of the microbial communities of roots in undisturbed ecosystems where major diseases rarely occur can assist in determining the key microorganisms that play a role in plant health (Linderman 1998). Improved formulations and delivery systems are also under development. Material inputs Biological control organisms purchased or made on-farm. Mechanism for conveying or incorporating biological controls into the soil. Equipment, such as irrigation pipes, sprayers, or fertiliser injectors, is often already available on farms. Factors required for use Know-how and training. Users must first identify biological controls that will be effective in the region. They must also be knowledgeable about pest and predator life cycles, appropriate timing of treatments, temperature, irrigation, soil types, application methods and optimal storage of products. In some countries official registration by pesticide authorities is required before products can be marketed. Users must be able to control or manipulate soil temperature, acidity and/or moisture to be within the appropriate range for activation. Biological controls are not compatible with some pesticide treatments. Steam treatments and fumigants also kill biocontrols, unless the biological controls are applied after the other treatment. Pests controlled Biological controls can suppress or control specific species of nematodes, fungi and soildwelling stages of insect pests. They are normally highly specific and cannot replace MB on their own, so they are best used as one part of a combined system. Tables through provide examples of biological agents that can be used for control of nematodes, fungi, and bacteria and insects, respectively. Certain biological control agents can be applied together to increase the range of pests controlled. They can be used curatively to reduce an existing infestation and/or as maintenance treatments to

55 Table Examples of soil-borne fungi and bacteria controlled or suppressed by biological controls Pathogenic fungi and bacteria Biological control agents Agrobacterium tumefaciens Agrobacterium radiobacter strain 84 Alternaria brassicicola Streptomyces griseoviridis strain K61 Alternaria spp. Bacillus subtilis Armillaria spp. Trichoderma harzianum, Trichoderma viride Botryosphaeria spp. Trichoderma harzianum, Trichoderma viride Botrytis cinerea Trichoderma harzianum Trichoderma spp. Botrytis spp. Streptomyces griseoviridis strain K61 Collectotrichum spp. Trichoderma harzianum Damping off diseases (fungi) Pseudomonas fluorescens Trichoderma spp. Didymella spp. Gliocladium catenulatum Erwinia amylovora Pseudomonas fluorescens A506 Fulvia fulva Trichoderma harzianum Fusarium oxysporum, Fusarium oxysporum non-pathogenic Fusarium moniliforme Fusarium spp. Bacillus subtilis Burkholderia cepacia type Wisconsin Gliocladium sp. Pseudomonas cepacia Streptomyces griseoviridis strain K61 Trichoderma harzianum, Trichoderma viride Heterobasidium annosum Phlebia gigantea Monilia laxa Trichoderma harzianum Phomopsis spp. Streptomyces griseoviridis strain K61 Phytophthora spp. Streptomyces griseoviridis strain K61 Trichoderma harzianum, Trichoderma viride Powdery mildew Ampelomyces quisqualis Pseudomonas solanacearum Pseudomonas solanacearum non-pathogenic Pseudomonas tolassii Pseudomonas fluorescens Pythium ultimum Pythium spp. Pythium sp. Rhizoctonia solani Rhizoctonia spp. Sclerotinia homeocarpa Sclerotinia sclerotiorum and Sclerotinia minor Sclerotinia sclerotiorum and other Sclerotinia species Sclerotinia spp. Sclerotium rolfsii Verticillium spp. Pythium oligandrum Burkholderia cepacia type Wisconsin Gliocladium virens, Gliocladium catenulatum Streptomyces griseoviridis strain K61 Trichoderma harzianum, Trichoderma viride Pseudomonas cepacia Bacillus subtilis Gliocladium virens, Gliocladium catenulatum Pseudomonas cepacia Trichoderma spp. Burkholderia cepacia type Wisconsin Trichoderma harzianum Coniothyrium minitans Trichoderma harzianum and certain other species of Trichoderma Bacillus subtilis Trichoderma spp. Trichoderma spp. Bacillus subtilis Trichoderma spp. Compiled from: MBTOC 1998, Fravel 1999, Gutierrez 1997, Lung 1999 Section 4: Alternative Techniques for Controlling Soil-borne Pests 43

56 Table Examples of insect pests (soil-dwelling larvae and pupae) controlled or suppressed by biological controls Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 44 Insect pests Agrotis ipsilon (cutworms) Bradysia spp. (a) Lycoriella mali (a) Peridroma sauci (cutworms) Popillia japonica (a) Sciara spp. (a) Various armyworms Various beetle larvae Various cutworms Fruit borer species (a) (a) Soil-dwelling larvae and/or pupae provide ongoing protection from pests. Predatory nematodes can act swiftly, while other nematodes have a slow effect, so efficacy can vary according to the type of biological control agent, the type of pest, the original level of infestation and soil conditions such as temperature. Yields and performance Biological controls need to be combined with other techniques in order to give efficacy and yields equal to MB fumigation. Other factors affecting use Suitable crops and uses Biological control products have been approved in some countries for many horticultural crops, nurseries, trees, turf, mushrooms and other crops. They can be used in greenhouses, seedbeds, nurseries and open fields. However, the appropriate applications vary greatly from one product to the next, so it is important to check local suitability before Biological controls Heterorhabditis bacteriophora + Steinernema carpocapsae Steinernema carpocapsae Steinernema carpocapsae Heterorhabditis bacteriophora + Steinernema carpocapsae Heterorhabditis bacteriophora Steinernema carpocapsae Steinernema carpocapsae, Steinernema feltiae Bacillus popilliae Beauveria bassiana Metarhizium anisopliae Steinernema feltiae Steinernema carpocapsae, Steinernema feltiae Steinernema carpocapsae Compiled from: Gutierrez 1997, Cherim 1998, commercial product information purchasing products. They are suitable for single, double- and multi-cropping systems. Suitable climate and soil types Biological controls need to be selected to suit the temperature range of the area where they will be used, because each organism has an optimum range for biological activity. They can be used in many soil types, although this may vary with the specific organism. The soil ph (acidity or alkalinity) can enhance or limit some biological controls. Toxicity and health risks Approved biological controls are generally safe for humans because they act against selected soil organisms. However, it is desirable to avoid breathing dusts or spray formulations, because dust in general is a health hazard and there is a possibility of allergic or intolerant reactions to foreign protein.

57 Safety precautions for users Approved biological controls are generally considered safe to users and rural communities, because their action is confined to specific soil pests. Special safety training is not required for registered products. Protective equipment should be used with formulations that generate dust or spray particles. Residues in food and environment Biological controls make a positive contribution to the soil environment. Approved organisms do not leave undesirable residues in food or the environment. Phytotoxicity Approved biological controls are not toxic to crops. Some actively promote crop growth. Impact on beneficial organisms Use of biological controls increases the population of beneficial organisms and generally increases biodiversity and antagonistic activity in the soil. Some predatory nematodes, however, may prey on certain beneficial organisms as well as pests. Ozone depletion Biological controls are not listed as ODS. Global warming and energy consumption Manufacturing of biological controls uses less energy than does production of MB. Tractor application requires use of fuel, similar to mechanised MB application; application via irrigation water does not. Other environmental considerations Product packaging produces small amounts of solid waste. Acceptability to markets and consumers Biological controls are very acceptable to supermarkets, purchasing companies and consumers because they enhance biological diversity and are seen to be a positive replacement for pesticides. Registration and regulatory restrictions Regulatory approval is required in some countries. In the past, some biological controls (e.g. cane toads in Australia) have been released without adequate scrutiny, leading to problems for indigenous species. For some years there has existed an international code of practice on the introduction of non-native organisms into new regions, and this is applied in many cases. Quality assurance schemes are necessary for manufacturers who produce biological controls. Cost considerations Material costs of biological controls are lower than MB. Labour costs for applying biological controls would be similar to the cost of a conventional pesticide spray or top dressing; application via irrigation systems entails negligible labour. Since biological controls need to be used as part of a combined system, it is necessary to calculate the cost of the other components before comparing to MB. Questions to ask when selecting the system Which soil pests need to be controlled? What degree of pest control is needed? Which biological controls will control these pests? To what degree? What practices are required to ensure that the biological control agent reaches the roots, thrives and is effective in the soil? What is the most effective form in which to apply the organism? What amount needs to be applied and how often? What measures need to be taken to control other key pests (IPM system)? Section 4: Alternative Techniques for Controlling Soil-borne Pests 45

58 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 46 What are the costs and profitability of this system compared to other options? Availability Biological control products are produced in a number of countries, including China, Czech Republic, Finland, France, Germany, Hungary, Italy, Jordan, Mexico, New Zealand, UK and USA. Suppliers of products and services Table gives examples of suppliers of biological control products and services. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Note that this table does not provide a complete list, and additional products can be identified by contacting your local agricultural supplier. It is always wise to consult independent sources of information in addition to commerical information about products. Table Examples of companies that supply biological control products and services Products or services Agrobacterium radiobacter Ampelomyces quisqualis Bacillus spp. Beauveria spp. Burkholderia cepacia Candida oleophila Coniothyrium minitans Fusarium spp. Gliocladium spp. Examples of companies (product name) AgBioChem Inc, USA (Galltrol-A) Bio-Care Technology Pty Ltd, Australia (Nogall, Diegall) New BioProducts Inc, USA (Norbac 84C) Ecogen Inc, USA (AQ10) Ecogen Inc, Israel (AQ10) AgraQuest Inc, USA (Serenade) Bayer Vital GmbH, Germany (FZB24) Gustafson Inc, USA (Kodiak, Epic) Helena Chemical Co, USA (System 3) KFZB Biotechnik GmbH, Germany (Rhizo-Plus) Lipha Tech, USA Microbial Solutions Ltd, South Africa Plant Health Care, USA Rincon-Vitova Insectaries Inc, USA (Activate) Minfeng Industrial Co, China (Miankangning) Biocaribe SA, Colombia Biological Control Products Pty Ltd, South Africa CV Solanindo Duta Kencana, Indonesia AgroSolutions, USA (Deny) Ecogen Inc, Israel and USA (Aspire) Bioved Ltd, Hungary (KONI) Prophyta Biologischer Pflanzenschutz GmbH, Germany (Contans) Agrifutur, Italy ICC-SIAPA, CER, Italy Natural Plant Protection, France (Fusaclean) SIAPA, Italy (Biofox) AgBio Development Inc, USA (PreStop, Primastop) Harmony Farm Supply, USA (SoilGard) Hyrdo-Gardens, USA (Gliomix) Kemira Agro Oy, Finland (PreStop, Primastop) continued

59 Products or services Gliocladium spp. (continued) Heterorhabditis sp. Mycorrhizae mixtures, e.g., Glomus brasilianum, Glomus clarum, Gigaspora margarita and others Myrothecium spp. Paecilomyces spp. Phlebia spp. Pseudomonas spp. Steinernema spp. Streptomyces spp. Table continued Examples of companies (product name) Thermo-Trilogy, USA (SoilGard) WR Grace & Co, USA ARBICO, USA BioLogic, USA E-Nema, Germany (Nemagreen) Green Spot Ltd, USA Hydro-Gardens Inc, USA ARBICO, USA (BioTerra Plus Mycorrhizae Inoculant; BioBlend Root Dip, Power Organics) BioOrganic Supply, USA BioScientific, USA BioTerra Technologies Inc, USA (BioTerraPlus Mycorrhizae Inoculant) EcoLife Corporation, USA Green Releaf, USA Plant Health Care, USA SouthPine Inc, USA Abbott Laboratories, USA (DiTera) Biocaribe SA, Colombia BioPre, Netherlands Microbial Solutions Ltd, South Africa Kemira Agro Oy, Finland (Rotstop) Hydro-Gardens Inc, USA (Rotstop) BioGreen Technologies, USA (BioReleaf) CCT Corporation, USA (Deny) EcoScience Inc, USA (Bio-save) EcoSoil, USA (BioJect system) Green Releaf, USA Mauri Foods, Australia (Conquer) Minfeng Industrial Co, China (Miankangning) Natural Plant Protection, France (PSSOL) Plant Health Technologies, USA (BlightBan) Soil Technologies Corp, USA (Intercept) Sylvan Spawn Laboratory, USA (Conquer, Victus) All Natural Pest Control Co, Canada Apply Chem (Thailand) Ltd, Thailand ARBICO, USA BioLogic, USA Green Spot Ltd, USA Hyrdo-Gardens Inc, USA (Guardian nematodes) Johnny s Selected Seeds, USA Nitron Industries Inc, USA Thermo Trilogy, USA AgBio Development Inc, USA (Mycostop) Green Spot Ltd, USA continued Section 4: Alternative Techniques for Controlling Soil-borne Pests 47

60 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 48 Products or services Streptomyces spp. (continued) Trichoderma spp. Other products and microbial antagonists (various formulations) Table continued Examples of companies (product name) Harmony Farm Supply, USA Kemira Agro Oy, Finland (Mycostop) Peaceful Valley Farm Supply, USA Plant Health Care, USA Rincon-Vitova Insecctaries Inc, USA; San Jacinto, USA (Actinovate) Abbott Laboratories, USA (Trichodex) Agricola Mas Viader, Spain Agrimm Technologies Ltd, New Zealand (Trichoflow-T, Trichodowels, Trichopel, Trichoject, Trichoseal) Al Baraka Farms Ltd, Jordan (Bio Cont-T) Aplicaciones Bioquímicas SL, Spain Biocaribe SA, Colombia Bio-Innovation AB, Sweden (Binab T) Biotechnology Research Unit for Estate Crops, Indonesia (Greemi-G) BioWorks Inc, USA (Rootshield, Bio-Trek T-22G, T-22 Planter Box) Borregaard and Reitzel, Denmark (Supresivit) CV Solanindo Duta Kencana, Indonesia (Bio-Job T01) De Ceuster Meststoffen nv, Belgium; Fruitfed Supplies Ltd, New Zealand (Trichoflow-T) FUNDASES Foundation, Colombia Green Spot Ltd, USA Grondortsmettingen DeCeuster nv, Belgium (Bio-Fungus) Henry Doubleday Research Association Sales, UK Jörgen Reitzel, Denmark Makhteshim Chemical Works Ltd, Israel (Trichodex) Makhteshim Ltd, USA (Trichodex) Microbial Solutions Ltd, South Africa Minfeng Industrial Co, China (Biocon-Tk) Mycontrol Ltd, Israel (Trichoderma 2000) NOCON SA de CV, Mexico (Control TL-2N) Plant Health Care,USA Wilbur Ellis, USA (Bio-Trek) Abbott Laboratories, USA, Malaysia (DiTera) ARBICO, USA Arbolan-PHC, Spain Asistec, Ecuador Bioma Agro Ecology, Switzerland Colegío de Posgraduados en Ciencias Agrícolas, Mexico Consejo Nacional de Agroinsumos Bioracionales, Mexico Eden BioScience, USA Fenic Co Inc, USA (F-68 Plus) Fruitfed Supplies Ltd, New Zealand (SC27) FUNDASES Foundation, Colombia continued

61 Products or services Other products and microbial antagonists (various formulations) (continued) Specialists and consultants on the selection and use of biological controls Table continued Examples of companies (product name) Laverlam, Colombia Megafarma SA de CV, Mexico Microbial Solutions Ltd, South Africa Min Feng Shi Ye Company, China Mycor Plant, Spain Natural Plant Protection, France (Phagus) NOCON SA de CV, Mexico Qingzhou Sheng Hua Zhi Pin Factory, China Rincon-Vitova Insectaries Inc, USA San Jacinto, USA (MicroGro) Triton Umweltschutz GmbH, Germany Biocontrol of Plant Diseases Laboratory, US Department of Agriculture, USA Biological Control Institute, Auburn University, USA Bio-Integral Resource Center, USA CIAA Agricultural Research and Consultancy Center, Colombia Consejo Nacional de Agroinsumos Bioracionales, Mexico Cornell University, USA EMBRAPA Biological Control Information System, Brazil FUNDASES Foundation, Colombia GTZ Integrated Pest Management project, Jordan Indian Agricultural Research Institute, India International Institute of Biological Control, Kenya, Malaysia and UK International Mycological Institute, UK International Organisation of Biological Control, Malaysia, Trinidad & Tobago, France, UK, Pakistan, Kenya National IPM Network, USA PBG Research Station for Floriculture and Glasshouse Vegetables, Netherlands University of California IPM Program, USA Dr Keith Davis, Rothamstead Experimental Station, UK Dr Mahomed Eddauodi, Institut National de la Recherche Agronomique, Morocco Dr Ronald Ferrera-Cerrato, Instituto de Recursos Naturales, Mexico Dr D Fravel, Biocontrol of Plant Diseases Laboratory, USDA, USA Dr Roberto García Espinosa, Colegio de Postgraduados en Ciencias Agricolas IFÍT, Mexico Dr Robert Hill, HortResearch, New Zealand Prof Harry Hoitink, Department of Plant Pathology, Ohio State University, USA Dr TA Jackson, AgResearch, New Zealand Dr Joseph Kloepper, University of Auburn, USA Dr Robert Linderman, Horticultural Crops Research Laboratory, USDA-ARS, USA Section 4: Alternative Techniques for Controlling Soil-borne Pests continued 49

62 Products or services Specialists and consultants on the selection and use of biological controls (continued) Table continued Examples of companies (product name) Dr Gerhard Lung, Institute of Phytomedicine, University of Hohenheim, Germany Dr Yitzhak Spiegel, Agricultural University, Israel Prof Alison Stewart, Lincoln University, New Zealand Prof Tang Wenhau, China Agricultural University, China Prof Gerhard Wolf, Institut für Pflanzenpathologie, Germany Note: Contact information for these companies is provided in Annex 6. Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 50

63 4.3 Fumigants and other chemical products Advantages Fumigants generally control a relatively wide range of pests. Fumigants and pesticides can be as effective as MB, if several techniques are combined. Some products are widely used, so materials and information are accessible. Application methods, equipment and pest control approaches are more akin to MB fumigation than are other types of alternatives. Disadvantages Most products are toxic to humans and non-target organisms. Many leave residues or breakdown products in water, air, soil, wildlife and/or crops, thus leading to concerns about environmental polution. Correct application techniques vary from product to product and are very important for efficacy. Products are not registered in some countries, restricting availability. Many require waiting periods longer than MB. Use requires safety equipment and compliance with safety restrictions. Technical description Fumigants are volatile chemicals that exist as gases or are converted into gases under typical field conditions. In contrast to other chemical products, which are normally active in solid or liquid form, fumigants move through the soil principally as a gas or vapour. Both types of products control pests because they are highly toxic to pests or because they generate toxic substances. To be effective they have to be present in sufficient concentrations to kill the target pests. Alternative fumigants and other chemical products do not kill the same wide range of pests as MB. Therefore, they are best used with other treatments or practices and/or employed selectively within an IPM system. Depending on the formulation, chemicals can be injected, sprayed on the soil surface, mechanically incorporated or distributed via irrigation pipes. Products to control nematodes are normally applied before planting, in the case of fumigants, or at the time of planting, in the case of pesticides. To prevent re-contamination of soil, hygienic practices, such as cleaning equipment before moving it and avoiding infected seeds and contaminated irrigation water, should be followed. Fumigants are often supplied in liquid form and require a minimum temperature of about 5 to 7 C. They include two groups: True fumigants, such as 1,3-dichloropropene and chloropicrin, which are volatile and able to move through the soil airspaces as gases or vapours. Non-true fumigants, such as metam sodium and dazomet, which act more like contact pesticides. For non-true fumigants, water is very important in moving the chemical through the soil to target pests. So in general soil should be quite moist when applying non-true fumigants and rather dry when applying true fumigants (Hafez 1999). True fumigants are often described as better nematicides than non-true fumigants, but non-true fumigants can be effective nematicides if applied in ways that ensure they reach target pests. Most are not effective against weed seeds Section 4: Alternative Techniques for Controlling Soil-borne Pests 51

64 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide but can control weeds if they are germinated by irrigation prior to the fumigation. Table compares the characteristics of some major fumigants. Table shows the categories of pests controlled by fumigants and pesticides. Fumigants registered in some or many countries include the following: Chloropicrin or trichloronitromethane is a liquid, which is injected into the soil, typically to a depth of 15 to 28 cm. The soil is subsequently covered with plastic or sealed. It diffuses well through soil but needs to be combined with other techniques to fully control weeds and nematodes. The acute toxicity and noxious smell of chloropicrin may limit its use in some areas. Dazomet s primary ingredient is tetrahy- dro-3,5-dimethyl-2h-1,3,5-thiadiazine-2- thione. It is registered or approved for use in many countries and formulated as a solid material in granular form, making it easier to handle than other fumigants. It is generally incorporated into the soil by roto-tilling. To aid distribution of dazomet, soil needs to be prepared prior to application, finely cultivated, above Table Comparison of technical characteristics of selected fumigants Physical Active Application Application Time before Fumigant form ingredient method rates planting Comments 1,3-D Liquid and 1,3-dichloro- Injected into soil, About 7-45 Soil temp emulsion propene then sealed or L/ha days before 5-25 C; at covered with planting least 10 - sheets; or via 15 C in drip irrigation wetter soils Chloro- Colourless Trichloronitro- Injected into soil, More than 14 Optimum picrin liquid methane covered with kg/ha days before soil temp plastic; or via planting C drip irrigation Dazomet Granules Tetrahydro- Mechanical days Not suitable 3,5,-dimethyl- distribution in kg/ha before for soil temp 2H-1,3,5- soil planting below 6 C; thiadiazine-2- soil must not thione be too wet or (produces MITC) too dry MB Gas Methyl Injected into soil About 7-14 Optimum soil bromide or released on kg/ha days before temp 5 - soil surface, planting 25 C under sheets Metam Liquid Sodium Applied on About Efficacy desodium methyl-dithio- soil, injected L/ha days before pends on carbamate or via drip planting application (produces inrrigation method. Soil MITC) temp 5-32 C; moisture at least 50-75% of field capacity 52

65 10 C and moist; soil covering is not necessary. Dazomet generates a fumigant gas called methyl isothiocyanate (MITC) and other fumigant breakdown products, such as carbon bisulphide and formaldehyde (MBTOC 1994). The soil persistence of these is influenced by temperature and moisture. If application conditions are sub-optimal, such as cool and wet, a longer waiting period before planting crops may be necessary to avoid phytotoxicity (toxicity to crops). 1,3-dichloropropene (1,3-D) is a halogenated hydrocarbon. It is formulated as a liquid and injected into soil, followed by sealing of the soil surface with a roller, water or plastic to trap the gas. Newer formulations can be applied via drip irrigation pipes under impermeable plastic sheets. The soil may be moist before application and the temperature should be at least 10 C. The toxicological profile of 1,3-D may limit its use in some areas. Methyl isothiocyanate (MITC) is a liquid that is injected into soil. It is mostly used in combination with 1,3-D to enhance nematode control. A waiting period of up to eight weeks may be Table Efficacy of fumigants and pesticides Fungal required for MITC and MITC-generators, such as metam sodium and dazomet. Problems with product stability and corrosion have limited the use and distribution of MITC (MBTOC 1994). Metam sodium consists of sodium methyl-dithiocarbamate, which generates MITC in the soil. Formulated as a liquid, it may be applied to the soil by injection or drip irrigation or sprayed onto the soil surface prior to tilling. The soil must be prepared and free from clods before application. Metam sodium does not distribute easily in the soil and can give variable pest control depending on soil temperature, texture, organic matter, moisture, ph and distribution. Water is essential for good movement in the soil. With improved application techniques and better surface sealing, metam sodium can give results equal to MB fumigation (MBTOC 1998). It can be combined with solarisation or other pesticides for greater efficacy. Metam sodium is registered in many countries and has been used for more than four decades in California USA for the production of tomato, strawberry and pepper crops. Pathogens Nematodes Insects Weeds Bacteria 1,3-D Chloropicrin Dazomet MB Metam sodium MITC Fungicides +++ Herbicides +++ Insecticides +++ Nematicides +++ Adapted : Porter 1999 Key: MITC-methylisothiocyanate 1,3-D-1,3-dichloropropene ++++ high degree of pest control +++ good control ++ some control + little control Soil Section 4: Alternative Techniques for Controlling Soil-borne Pests 53

66 Table Examples of commercial use of fumigants Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 54 Chemical Crop Examples of countries Metam sodium Cucurbits (cucumber, melon, etc.) Costa Rica, Egypt, Jordan, Mexico, Morocco Metam sodium Strawberries Netherlands, Morocco, Spain Metam sodium Open field tomatoes and peppers Australia, Costa Rica, Egypt, Mexico, Morocco, Spain, Zimbabwe Dazomet Open field tomatoes and peppers Europe, Japan Dazomet Strawberries Netherlands, Spain Dazomet Tobacco seedlings Brazil, USA Chloropicrin Cucurbits, tomatoes Japan, Zimbabwe 1,3- dichloropropene Stone fruit Spain, USA 1,3- dichloropropene Open field tomatoes and peppers Costa Rica, Honduras, Italy, Japan, Mexico, Spain, USA Metam sodium + Cut flowers, flower bulbs Netherlands 1,3- dichloropropene Mixtures of soil fumigants provide a spectrum of pest control similar to MB. Mixtures of 1,3-D and chloropicrin, for example, are registered in some regions. Soil may be pre-irrigated to stimulate nematode development to active forms and then allowed to become fairly dry by the time the fumigant product is applied. The liquid is often applied mechanically by soil injection to a depth of about 46 cm, with the soil surface sealed. The soil should usually be left undisturbed for at least 7 days and planting should be delayed for 21 days or more if conditions have been cold and wet. The efficacy of fumigants depends greatly on the preparation and application method, because many factors influence efficacy, including the pest species, degree of infestation, type of fumigant, soil preparation, soil type, ph, organic matter, presence of crop residues, soil depth, soil temperature, application rate and application method. Soil pests should be identified before selecting the appropriate fumigant and co-treatments. Compiled from: MBTOC 1998 Good soil preparation (e.g., producing a fine tilth) is normally important for helping fumigants to diffuse through the soil and reach the pests. Finer soil textures with a high percentage of silt and clay have smaller pore sizes, and this characteristic tends to block the movement of fumigants. So these soils generally require higher application rates. Debris from the previous crop may harbour pests and should be chopped up and incorporated into the top 10 cm of soil and allowed to decompose before fumigation. Fumigants are generally most effective when the soil temperature is 21 to 27 C at a depth of 20 cm, although fumigation can be carried out when soil temperatures are 7 to 30 C at 20 cm depth (Hafez 1999). All fumigants and pesticides are normally required to carry instructions for application methods and safety precautions, and these instructions should be followed in all cases. In general, deep placement of a fumigant in the soil (e.g. injecting it to 38 to 46 cm depth) gives better pest control than with shallow placement (e.g. 15 to 23 cm depth).

67 Likewise, applying the fumigant to the entire field area is more effective than placing it only along the rows where crops will be planted. A number of factors influence the rate at which fumigants become active. For example, clay soils tend to slow the conversion of 1,3- D with chloropicrin to the gas phase, while they increase the rate at which metam sodium is converted to MITC. A higher soil ph and available copper, iron or manganese in the soil can speed up the conversion of metam sodium to MITC. Raised soil temperatures also increase the rate of conversion of metam sodium to MITC and the conversion of 1,3-D + chloropicrin to the gas phase (Hafez 1999). Pesticide products Pesticide products are chemicals with toxic properties. They are available as liquids, granules or powders. Their modes of action vary; for example, some kill by contact and others by systemic action. They tend to be effective against specific sub-groups or groups of pests. Some control a wide range of species, while others control a very limited range, so soil pests must be identified before appropriate products can be selected. The names of the main groups of pesticides indicate the types of pests that they control: Nematicides control nematodes. Fungicides control fungi. Herbicides control weeds. Insecticides control insects. These groups are not discussed in detail, because the available pesticide products vary greatly from country to country, depending on the approved formulations. Relevant information can be obtained from agricultural suppliers and the government departments responsible for pesticide registration. Current uses Both fumigants and non-fumigant pesticides are used commercially. The fumigant metam sodium is used in many countries, including Israel, Italy, Morocco, Spain, southern France and USA, while dazomet is used in regions such as Argentina, Australia, Europe and Japan (MBTOC 1998). Mixtures of 1,3- dichloropropene with methylisothiocyanate and 1,3-dichloropropene with chloropicrin have been used for many years on a variety of crops in North America (MBTOC 1994). Table provides more examples of the commercial use of fumigants. Variations under development Some potential fumigants are being examined in trials, including: Methyl iodide. Ozone. Sodium tetrathiocarbonate. Anhydrous ammonia. Furfuraldehyde. Material inputs Fumigant or pesticide products. Equipment for injecting, spreading or distributing the products into soil. Equipment to seal the soil surface or plastic sheets to cover the soil. Safety equipment. Factors required for use Fumigants and pesticides should only be used where government registration of the chemical has been given for the specific crop/situation in question. This will vary markedly from one country to the next, and even from state to state in some countries. To determine the registration status and permitted uses of products, contact the national or state Section 4: Alternative Techniques for Controlling Soil-borne Pests 55

68 Table Examples of yields from fumigants and pesticides Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 56 Yields from Crop/Region Treatment chemical treatments Yields from MB Tomatoes in Florida 1,3-D + oxamyl (trial) kg/m kg/ m 2 Tomatoes in Florida dazomet + pebulate 4.1 kg/ m kg/ m 2 herbicide (trial) Tomatoes in Florida metam sodium kg/plot 44.5 kg/plot chloropicrin + pebulate herbicide (trials, various rates) Tomatoes in Florida 1,3-D + pebulate herbicide kg/plot 44.5 kg/plot (trial, various rates) Tomatoes Olympic metam sodium or 1,3-D 86.4 t/ha 87.1 t/ha cultivar with chloropicrin Tomatoes Sunny metam sodium or 70.5 t/ha 67.5 t/ha cultivar 1,3-D with chloropicrin Cucurbits in Spain metam sodium (trials) 1,928 kg/plot 1,991 kg/plot Strawberries in Spain chloropicrin (trials) 796 g/plant 768 g/plant Strawberries in Spain 1,3-D + chloropicrin (trials) 779 g/plant 768 g/plant Strawberries in Florida 1,3-D + chloropicrin (trials) 3,333-3,620 flats/ha 3,511-4,131 flats/ha Strawberries in Florida chloropicrin (trials) 3,311-4,040 flats/ha 3,511-4,131 flats/ha Strawberries in dazomet + chloropicrin 4.4 kg/plot (av.) 4.6 kg/plot (av.) California + 1,3-D Compiled from: MBTOC 1998, Dickson et al 1995, Dickson et al 1998, Locascio et al 1999, López-Aranda 1999, McGovern 1994, Sanz et al 1998, Webb 1998 authority responsible for pesticide registration, which is often located in the Ministry of Agriculture or Health. Know-how is important for proper application of the products, since efficacy depends greatly on good distribution in the soil. Most fumigants need a particular soil temperature range, soil texture and moisture level for even distribution. Fumigants and pesticides require knowledge of safety measures. Pests controlled Fumigants and other pesticides vary in the range and efficacy with which they kill pests. In general, they do not kill as wide a range of pests as MB, so they are best used with other treatments as part of an IPM system. Table indicates the main pest groups controlled by available chemicals: Chloropicrin is highly effective for the control of soil-borne fungi, about 20 times more effective than MB in this respect (Desmarchelier 1998). It controls germinated weeds and some arthropods. It is a weak nematicide and does not kill dormant or non-germinating weed seeds (MBTOC 1998). Dazomet provides control of soilborne fungi, some weeds and certain nematodes. 1,3-dichloropropene provides effective control of nematodes but little control of diseases and weeds (Johnson and

69 Feldmesser 1987, Rodríguez-Kábana et al 1977). Mixtures of 1,3-dichlorpropene and chloropicrin are effective in controlling nematodes, deep-rooted perennial weeds and soil-borne insects. MITC is highly effective for controlling a wide range of soil-borne fungi, arthropods, some weeds and limited species of nematode species (MBTOC 1998). Metam sodium provides effective control of fungal pathogens, arthropods, certain weeds and a limited number of nematode species (MBTOC 1998). Nematicides control nematodes or specific types of nematodes, and some soil insects. Fungicides control specific fungi or groups of fungi. Herbicides can control a narrow or wide range of weeds, depending on the specific product. As mentioned previously, efficacy can be affected greatly by soil type, soil preparation and application methods. The efficacy of fumigants against nematodes and weeds can be improved by pre-irrigation to encourage nematode development and weed germination. Additional information on the types of pests that specific products will control can be obtained from approved product labels and extension authorities. Regional information is also available on extension websites, such as the University of California Pest Managment Guidelines (see list of websites included in Annex 7). Yields and performance Yields can be lower than, equal to, or higher than those achieved using MB, depending on the chemical and application method. Table provides some examples of yields. Other factors affecting use Suitable crops and uses Fumigants and pesticides can be used for the horticultural crops for which they are registered in a country or state. It is feasible to use them in open fields, greenhouses, tunnels, seedbeds, nurseries. However, the permitted applications will vary greatly from country to country. They can be used in single and double-cropping systems. Suitable climates and soil types Most fumigants work within certain temperature ranges and require a minimum of about 5-7 C. Some chemicals are not effective if the climate or soil is too wet or too dry. Efficacy also varies with the soil type, particle size, ph and percentage of organic matter. Lighter soils generally require lower fumigant application rates, while heavier soils generally require higher application rates. Additional information on appropriate conditions can be obtained from product labels or extension agencies. Toxicity and health risks Fumigants and pesticides are designed to be toxic to living organisms. The main hazard to field workers is during mixing and handling, but they can also drift to neighbouring farms and communities, posing risks to human health, crops and wildlife. Fumigants and some pesticides are acutely toxic, i.e. exposure to sufficient concentrations can rapidly produce symptoms of poisoning or ill health. Others may be associated with chronic toxicity, i.e. symptoms of ill health may develop a long time after exposure has occurred. Annex 3 gives data sheets for the major fumigants. Safety precautions for users Safety equipment and training is necessary for users and for the protection of local communities. All safety instructions given by product labels and health authorities must be followed. Section 4: Alternative Techniques for Controlling Soil-borne Pests 57

70 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Residues in food and environment Many fumigants and pesticides leave undesirable residues and metabolites in air, soil, crops and food. Some residues can move into surface or groundwater, and some persist in the environment for a long time and may accumulate in the tissues of living organisms. Phytotoxicity Fumigants often leave phytotoxic residues, but this problem is normally overcome with a waiting period of about two to three weeks or longer before planting. Impact on beneficial organisms Fumigants generally kill many beneficial organisms in the soil, while pesticides kill certain groups of organisms. For example, fungicides often kill or suppress beneficial fungi. Ozone depletion Commercially available fumigants such as metam sodium and 1,3-D are not ODS. Methyl iodide has a low ODP. Global warming and energy consumption As with MB, energy is used in the production, transportation, use and disposal of fumigants and pesticides and related equipment, such as application machinery and plastic sheets. Other environmental considerations Some fumigants and pesticides are manufactured from non-renewable resources such as oil. After use, chemical residues do not disappear but are converted into metabolites and other residues, some of which are harmful to wildlife and the environment. Empty containers contain toxic residues and pose a special waste problem, which some regions are addressing with waste collection programmes. Acceptability to markets and consumers Consumers have concerns about undesirable pesticide residues in food, water and the environment. Purchasing companies generally accept the use of fumigants and pesticides where they meet the regulatory requirements for application and residues. However, some major supermarkets are demanding minimal residues and reduced reliance on pesticides. Registration and regulatory restrictions Fumigants and other pesticides have to be registered (approved and permitted) by national and/or state pesticide regulation authorities, and regulation may restrict sale, use and disposal. Authorities normally specify the crops for which particular products can be used, the maximum application rates, and other conditions that may limit their use. To find out whether a fumigant or pesticide is registered for your crop/application, contact the pesticide registration authority at the appropriate national or state level. Agrochemical suppliers can also provide information on the regulatory status of chemicals, but the information may not be up to date or reliable. The sale of pesticides is also restricted by a number of international agreements. An international code of practice developed by the Food and Agriculture Organization of the United Nations provides guidelines for the marketing and use of pesticides. Certain pesticides are subject to the Rotterdam Convention, an international agreement that requires Prior Informed Consent or PIC procedures to be followed before import. A new agreement will limit specific Persistent Organic Pollutants (POPs); international trade and disposal of pesticides is subject to the Basel Convention on hazardous wastes. 58

71 Cost considerations Examples of chemical costs per hectare in the USA (UCD Dept Nematology 1999, EPA 1997): MB with plastic sheets US$ 1,410-2,985 MB without sheets US$ 690-1,000 Chloropicrin US$ 1,600-2,965 Dazomet US$ 1,792-2,990 1,3-dichloropropene US$ 250-1,235 Metam sodium US$ 370-1,000 Nematicides US$ In practice, overall costs may be higher than with MB, because several treatments or combinations are often required to replace MB. Where specially adapted machinery is necessary, capital costs will be higher. Labour costs vary and can be higher than MB if additional soil preparation is necessary. Questions to ask when selecting the system Which soil pests need to be controlled? Which registered fumigants or pesticides would control those specific pests? What other components would need to be used in an IPM system? What is the optimal application method and equipment? What safety equipment and/or training is required? Will the residues fall within regulatory and market requirements? What is the cost and profitability of the system compared to other options? Availability Some fumigants and a range of non-fumigant pesticides are available in most countries. The precise list will vary from one country or state to the next, depending on regulatory and marketing policies. Suppliers of products and services Table lists manufacturers of major fumigants and gives examples of specialists. A detailed list is not provided, because the available products vary so greatly from one country to the next. In most cases your local agricultural supplier can provide information about products available locally, while permitted uses can be checked with the pesticide registration authority at the national or state level. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Table Examples of fumigants producers and specialists Products and services 1,3-dichloropropene Chloropicrin Dazomet Metam sodium Nematicides Specialists, advisory services and consultants Companies DowAgroScience, USA Refer to local agrochemicals suppliers Great Lakes Chemical Corp, USA Refer to local agrochemicals suppliers BASF, Germany Refer to local agrochemicals suppliers Amvac Chemical Corp, USA Refer to local agrochemicals suppliers Refer to local agrochemicals suppliers Agriphyto, France Aplicaciones Bioquímicas SL, Spain Asociación Colombiana de Exortadores de Flores (ASO COLFLORES) Colombia Danish Institute of Agricultural Science, Denmark continued Section 4: Alternative Techniques for Controlling Soil-borne Pests 59

72 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 60 Products and services Specialists, advisory services and consultants (continued) Table continued Companies Department of Nematolody, University of California at Davis, USA for nematode management information DLV Advisory Service, Netherlands FMC Foret Grupo Agroquimicos, Spain PBG Research Station for Floriculture and Glasshouse Vegetables, Netherlands Statewide Integrated Pest Managment Project, University of California, USA for management of a wide range of pests and diseases Dr Antonio Bello and colleagues, CCMA, CSIC, Spain Dr Mohamed Besri, Institut Agronomique et Vétérinaire Hassan II, Morocco Dr William Carey, Auburn University, USA Dr G Cartia, Universita di Reggio Calabria, Italy Mr Dermot Cassidy, Geest, South Africa Dr Vincent Cebolla, Instituto Valenciano de Investigaciones Agrarias, Spain Dr Dan Chellemi, USDA-ARS, USA Dr Don Dickson, University of Florida, USA Dr John M Duniway, University of California, USA Dr Clyde Elmore, Weed Science Program, University of California, USA Dr J Fresno, INIA, Spain (vineyards) Dr Abraham Gamliel, Institute of Agricultural Engineering, Israel Dr A López García, FECOM, Spain Dr James Gilreath, IFAS, University of Florida, USA Prof M Lodovica Gullino, University of Turin, Italy Dr A Minuto, University of Turin, Italy Dr Saad Hafez, University of Idaho, USA Dr Seizo Horiuchi, National Research Institute of Vegetables, Ornamental Plants & Tea, MAFF, Japan Dr Steven Fennimore, Department of Vegetable Crops, University of California, USA (weeds) Prof Jaacov Katan, Hebrew University, Israel Dr Nancy Kokalis-Burelle, Horticultural Research Laboratory, USDA-ARS, USA Dr Kirk Larson, University of California, USA Dr Michael McKenry, University of California, USA Dr Robert McSorley, Department of Nematology and Entomology, USA Dr Peter Ooi, FAO Integrated Pest Control Intercountry Programme, Philippines Ms Marta Pizano, Hortitecnia, Colombia (cut flowers) Dr Ian Porter, Knoxfield Research Station, Australia Dr Rodrigo Rodríguez-Kábana, Univeristy of Auburn, USA Dr Lim Guan Soon, International Institute of Biological Control, Malaysia Dr Donald Sumner, Dept. Plant Pathology, University of Georgia, USA Dr J Tello, Dpto Biología, University of Almería, Spain Dr Thomas Trout, USDA-ARS, USA Dr Husein Ajwa, USDA-ARSUSA Mr Peter Wilkinson, Xylocopa, Zimbabwe Note: Contact information for these producers and specialists is provided in Annex 6.

73 4.4 Soil amendments and compost Advantages Soil amendments stimulate the activity of beneficial soil organisms and lead to other soil changes that directly or indirectly reduce or suppress pests. Pest suppression can continue for several seasons. Organic matter improves soil texture, providing crop nutrients and reducing fertiliser costs. Raw materials that are suitable as soil amendments are often non-toxic and do not require special safety training. A wide range of waste materials can be used as amendments. Use may be limited to localities where materials are readily available, otherwise transport costs may be unacceptable. It is necessary to have quality controls and to avoid materials that may be contaminated with undesirable components such as heavy metals or weed seeds. Know-how is required for effective use; efficacy varies with the type of soil and type of amendment. Technical description Soil amendments are organic materials, such as crop residues and waste materials from forestry and food processing industries. These amendments decompose when they are added to soil, supporting and promoting the activity of beneficial soil microorganisms that suppress certain pathogenic fungi and nematodes. Disadvantages Amendments suppress specific pathogens and nematodes and do not control weeds and insects, so they need to be combined with other techniques. Amendments are normally applied in large quantities. While MB kills pathogens very quickly, amendments and composts typically suppress or eradicate pathogens slowly over a long period of time (Cohen et al 1998, De Ceuster and Hoitink 1999). Amendments, therefore, must be applied well before pathogens reach populations capable of causing losses, and this requires more management. Use of soil Table Mechanisms in the control of Verticillium dahliae in soil following the addition of nitrogen-rich amendments Factor NH 3 mechanism HNO 2 mechanism Minimum lethal concentration > 170 ppm (N) in solution > 2ppm (N) in solution (24 hours) Location Soil solution or atmosphere Soil solution or gas Type of amendment Organic-N products (> 8% N), Organic-N products, fertiliser - urea, anhydrous NH 3 N (not NO 3 ) Rate of application > 1,600 kg N/ha or > 20 t/ha > 400 kg N/ha or > 20 kg organic-n product NO N/ha Determining soil properties Organic matter ph < 6.0, poor acid buffering ability, rapid nitrification Time after amendment 4-14 days 2-6 weeks Phytotoxicity Planting delayed 1-2 months Not evident Source: Tenuta and Lazarovits 1999 Section 4: Alternative Techniques for Controlling Soil-borne Pests 61

74 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 62 amendments requires careful monitoring for particular pest problems, with greater attention to pest biology. To replace MB, amendments generally need to be used with other control techniques as part of an IPM system. Amendments are incorporated into the soil in substantial quantities, normally in excess of 30 t/ha. Use of locally available waste materials can keep transport costs at an acceptable level. Soil amendments should be derived from materials that are free from plant pests and pathogens, or they should be composted at temperatures that kill pathogens. They must also be free from contaminants that could cause phototoxicity (toxicity to plants) or undesirable food residues. Substances that can be used as soil amendments include the following: Compost made from a wide variety of waste materials, e.g. crop residues and animal manure. Composted sewage sludge, if it is free from pathogenic organisms and heavy metals. Mushroom industry waste. Animal manures and wastes from meat, dairy and poultry production. Green manures, i.e. crops that are specially grown and incorporated into the soil while they are still green. Oil cakes or oilseed meals such as cottonseed meal or soy meal. By-products from food processing, e.g. fruit skin, pulp and culls. By-products from fish processing, e.g. fishmeal, fish emulsion, shellfish waste, and chitin from the pulverised shells of crabs and lobsters. By-products from the forest and paper industries, e.g. waste wood, bark, sawdust and paper mill digests. When amendments are added to soil, they are decomposed by microorganisms. This stimulates microbial activity and increases the total number of soil fungi and bacteria by 100- to 1000-fold, while decreasing the number of pathogens (Lazarovits et al 1997, Anon 1997). The chemical composition and physical properties of the amendments determine the types of microorganisms involved in decomposition and hence their efficacy. Certain nitrogen-rich amendments are capable of being converted in the soil to nitrate or yielding nitrous acid directly. Such amendments can kill the microsclerotia of Verticillium dahliae and other soil-borne pathogens, providing an effective broad-spectrum alternative to MB for certain soils (Tenuta and Lazarovits 1999). Examples of these amendments include poultry manure, soy meal and feather meal. Soil ph values above 8.5 are required for the ammonia mechanism, while ph values below 5.5 are required for the nitrous acid mechanism (Tenuta and Lazarovits 1999). The more successful nitrogen-rich amendments are reported to be ones that raise soil ph temporarily above 8.5 for a few weeks, allowing ammonia to be effective, and then falling back to a ph below 5.5, allowing the action of nitrous acid for 2 to 6 weeks (Table 4.4.1). Composting of organic materials speeds up the rate at which they decompose. Compost, used for centuries to maintain plant health (Hoitink et al 1997), can be made from many types of organic waste, provided the wastes are free from harmful contaminants or diseased crop residues. Each type of compost has its own characteristics. A compost pile, typically several metres wide, is made of layers of crop residues and animal manure, kept slightly moist but not wet. The site must be protected from sun and windblown seeds. Raw organic material is converted into compost, decomposed by the action of bacteria and fungi. Temperatures in the centre of the pile can reach 60 to 70 C,

75 killing some weed seeds and pathogens. Pests in cooler sections of the pile are not killed, but many pathogens will be killed if the compost is turned or mixed frequently and thoroughly. Turning also prevents the development of undesirable sour compost and offensive odours. Composting time can vary from three weeks to many months, depending on the method. Compost is widely used in the Colombian cut flower industry and is typically made in four to five months. Production time is reduced by several practices: Cutting raw materials in small pieces (< 4 cm long). Selecting raw materials to provide a carbon/nitrogen ratio of about 30:1. Adding material containing beneficial microorganisms, such as old compost or manure. Controlling ph and moisture. Turning the pile frequently. Disease-suppressive compost is also used by some cut flower producers in Colombia, where a microbial broth is made on-farm and added to the compost pile to increase the variety and numbers of beneficial soil microorganisms. The resulting compost helps to suppress many soil-borne pathogens, provides nutrients and improves soil texture. A number of factors must be controlled for consistent effects. These include the composition of the organic matter; the type of composting process, if any; the stability or maturity of the material; available plant nutrients; application rates; and time of application. Some important issues to consider are outlined below: Large quantities of amendments are required. This makes them expensive, unless cheap or waste materials are available locally. Because the effectiveness of nitrogenrich amendments varies from one soil to another, amendments can give inconsistent control of pathogens from field to field. Scientists in Ontario have developed a pre-application soil test that will test the suitability of a specific amendment for the field (Tenuta and Lazarovits 1999). The composition and quality of raw materials varies greatly and must be managed with quality control systems. Amendments and composts prepared from manures may contain high amounts of sodium and chlorides. Application of such materials well ahead Table Examples of commercial use of soil amendments (normally used with other techniques) Crops Soil amendments Examples of countries Tomatoes Cattle manure Morocco Tomatoes, cucurbits Farm-made compost Egypt Watermelons Manure Mexico Cut flowers Farm-made compost from mixed wastes Mexico Cut flowers Farm-made compost Colombia Nurseries Compost from municipal waste USA (California) Vineyards Manure Spain Various crops Various soil amendments Many countries Compiled from: MBTOC 1998, Batchelor 1999 Section 4: Alternative Techniques for Controlling Soil-borne Pests 63

76 of planting time, however, can alleviate problems with these materials. In addition to suppressing pests, soil amendments provide the major advantages of improving soil texture and structure and providing a range of nutrients for plants, which can save fertiliser costs. Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 64 The level of plant nutrients may vary from batch to batch, so crop fertilisers must be adjusted to compensate. Excessive nitrogen can be a problem with manures, while nitrogen deficiency is a danger with wood residues. In some cases, amendments need to be diluted by mixing with other types of amendments. The level of decomposition of amendments and composts affects pest control. Fresh organic matter does not support beneficial microorganisms, even when inoculated with the best strains. High concentrations of free nutrients, such as glucose or amino acids, in fresh crop residues repress the production of enzymes required for beneficial organisms such as Trichoderma. Composts must therefore be stabilised well enough and colonised to the degree that they support microbial activity (De Ceuster and Hoitink 1999). The variability of amendments and composts can make them difficult for farmers to use successfully, but this can be addressed by introducing quality controls on production and establishing guidelines for the use of specific formulations (De Ceuster and Hoitink 1999). Current uses Soil amendments were traditionally used as a method of controlling soil-borne pests and are now receiving renewed attention. Compost, for example, has reduced or eliminated MB use in a number of large commercial nurseries in California (Quarles and Grossman 1995). In Morocco, cattle manure reduces the incidence of Fusarium and Verticillium wilts in tomatoes (Besri 1997). Other examples of commercial use of soil amendments are provided in Table Biofumigation is another recently developed alternative, employing specific types of amendments that produce fumigant gases when they decompose (Kirkegaard et al 1993, Mathiessen and Kirkegaard 1993, Bello 1998, Bello et al 1997, 1998 and 1999). Brassica crop residues, for example, produce volatile chemicals such as methyl isothiocyanate and phenethyl isothiocyanate (Gamliel and Stapleton 1997). Biofumigation stimulates soil microbial activity and increases populations of nematodes that feed on bacteria or fungi and populations of benefical predatory nematodes (MBTOC 1998). Biofumigation is more effective when combined with solarisation, because the plastic traps gases and raises soil temperatures (Bello et al 1998). It has been used successfully in the production of bananas, tomatoes, grapes, melons, peppers and other vegetables (Bello et al 1999, Sanz et al 1998). Table Comparison of yields from soil amendments and other techniques versus MB examples Yields from soil amendments Crop/country combined with other techniques Yields from MB Watermelons, Mexico 45 tonnes/hectare 20 tonnes/hectare Cut flowers, Mexico 10,800 stems/160 m 2 8,400 stems/160 m 2 Carnations, Colombia 10.5 bunches/ m bunches/ m 2 Chrysanthemums (Fuji), Colombia 5.8 bunches/ m bunches/ m 2 Compiled from: Batchelor 1999

77 Variations under development Research on how amendments work in different types of soil is currently underway, and improved understanding in this area could increase efficacy and reduce application rates and related costs. Material inputs Organic materials (30-100t/ha). Transport for bringing material to the farm and equipment for incorporating amendments into the soil. For biofumigation, plastic sheets laid mechanically or by hand. Factors required for use Local sources of cheap organic matter, such as wastes or by-products. Quality control to ensure that harmful contaminants are avoided. For compost: adequate space and wellaerated areas, careful sorting of residues and regular turning and management. Good management to ensure the efficacy of disease-suppressive compost. Know-how, training and careful management. Pests controlled Soil amendments do not control weeds and soil insects, but until the 1930s, organic amendments consisting of animal and green manures were among the principal methods of controlling soil-borne diseases. The following are among the soil-borne fungi and nematodes that can be controlled or suppressed by various types of soil amendments: Blood or fishmeal incorporated into the soil at 10 tonnes per acre has been shown to completely inhibit Verticillium infection in tomatoes (Anon 1997). Poultry manure, urea, soy meal and other amendments that can be converted to nitrate or HNO 2 in the soil can kill the microsclerotia of Verticillium dahliae (Tenuta and Lazarovits 1999). Composted softwood and hardwood bark reduce pathogens such as Pythium ultimum. Composted bark amendments control Pythium and Phytophthora root rots most effectively in container media (Hardy and Sivasithamparam 1991, Ownley and Benson 1991); however the physical and chemical properties of the mixes must be ideal for this to occur. A composted pine bark mix fortified with Flavobacterium balustinum and Trichoderma hamatum is very effective in controlling Fusarium wilt of cyclamen and Rhizoctonia diseases as well as Pythium and Phytophthora root rots in potted greenhouse crops (Krause et al 1997). Rhizoctonia solani is not normally controlled in the first few weeks after applying amendments but can be controlled by well-cured composts or by incorporating composts in the fields well ahead of planting (Kuter et al 1988, Tuitert et al 1998). Fusarium crown rot of Chinese yam is suppressed in sandy soil amended with composted larch bark, replacing MB if a spray of benomyl is also applied to the soil at planting (Sekiguchi 1977). Chitin increases populations of beneficial actinomycetes and other microorganisms and suppresses some plant-parasitic nematodes (MBTOC 1998, Chaney et al 1992). Cattle manure application (>60t/ha) has been shown to reduce incidence of Fusarium and Verticillium wilts in tomato in Morocco (Besri 1997). Disease-suppressive compost used in Colombia helps to suppress many soilborne pathogens in cut flower production (Batchelor 1999). Section 4: Alternative Techniques for Controlling Soil-borne Pests 65

78 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 66 The action of amendments can be relatively rapid. Nitrogen-rich amendments, for example, kill microsclerotia within 7 to 10 days (at 7 to 24 C) when the soil ph is high (Tenuta and Lazarovits 1999). Yields and performance Organic amendments need to be combined with other techniques in order to give yields equal to MB fumigation. Repeated trials in nurseries producing Douglas fir and ponderosa pine in Oregon and Idaho USA found that bare fallow with sawdust soil amendments resulted in seedling quality and quantity comparable to fumigation (USDA 1999). Other examples of yields from soil amendments used in combination with other techniques are provided in Table Other factors affecting use Suitable crops Soil amendments can be used for most horticultural crops, although some materials, such as municipal compost, may be suitable only for non-food crops. Amendments and compost can be used in open fields, greenhouses, seedbeds and nurseries. They can be used for single and double cropping. Suitable climates and soil types The use of soil amendments is restricted to climates and times of year when temperatures are conducive to biological activity. Soil amendments can be used with many different types of soil, but some materials need to be matched to specific types of soil. They improve the texture of poor soils. Toxicity and health risks Soil amendments are not normally toxic in themselves, although materials like sewage sludge can contain organisms that are pathogenic to humans and undesirable for use with crops. Certain amendment materials could generate noxious substances if improperly handled. There are no risks of toxicity if amendments are selected and used properly. Safety precautions for users Safety training is desirable for anyone handling animal wastes. Materials that contain or generate contaminants must be avoided. For example, sewage is not suitable as a soil amendment if it contains heavy metals or pathogenic microorganisms. Residues in food and environment Provided soil amendments are properly selected, there will be no undesirable residues in food or the environment. Phytotoxicity A waiting period of approximately two to four weeks may be necessary before planting crops. For certain types of amendments and crops the waiting period may be substantially longer. Compost must be produced under quality control standards to exclude unsuitable raw materials, maintain aerobic conditions, and prevent the compost from producing certain acids that can be toxic to plants. Impact on beneficial organisms Soil amendments have a positive effect on beneficial organisms. Ozone depletion Soil amendments are not ODS. Global warming and energy consumption The energy use associated with transportation of organic amendments can be minimised by using local supplies. Other environmental considerations Soil amendments normally come from renewable resources. Use of soil amendments does not generate waste. On the contrary, it provides an opportunity to use waste materials constructively.

79 Acceptability to markets and consumers Soil amendments are very acceptable to consumers because they are seen as natural treatments. They are increasingly acceptable to companies that purchase fresh produce, provided that quality controls are used. Registration and regulatory restrictions Soil amendments do not require registration as pesticides. However, it is desirable that health authorities place restrictions on the types of materials that can be used as amendments to prevent use of materials containing undesirable contaminants or dangerous microorganisms. The US California Department of Food and Agriculture, for example, regulates the manufacture, labeling and marketing of amendments in the state. Questions to ask when selecting the system What sources of clean, cheap, waste organic materials are available locally? Which soil pests need to be controlled? Which available materials will control these pests? What amounts needs to be applied and how? What is the most effective time to apply the amendments? What other measures need to be taken to control the pests? What are the costs and profitability of this system compared to other options? Cost considerations Costs depend mainly on the source of the amendment and its transportation. To be cost-effective, soil amendments generally need to be waste materials or by-products from local sources. Material costs can be similar to or cheaper than MB if amendments are waste products; the costs are likely to be higher than those associated with MB if amendments are specially manufactured. Labour costs may be slightly higher for incorporating organic amendments into soil; a study in Spain found that labour for biofumigation was US$ 584/ha compared to $478/ha for MB (Bello et al 1999). Availability Organic waste materials are available in most areas. Suppliers of products and services Table provides examples of suppliers and specialists in soil amendments, composts and biofumigation. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Table Examples of companies that supply products and services for soil amendments and compost Products and services Soil amendments such as nitrogen-rich materials, chitin-protein products, composts Examples of companies (product name) Abonos Naturales Hnos Aguado SL, Spain Agro-Shacam SL, Spain Aplicaciones Bioquímicas SL, Spain ARBICO, USA Biocaribe SA, Colombia BioComp Inc, USA continued Section 4: Alternative Techniques for Controlling Soil-borne Pests 67

80 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 68 Products and services Soil amendments such as nitrogen-rich materials, chitin-protein products, composts (continued) Compost inoculants Compost maturity test kit, thermometers, etc. Biofumigation products and specialists Specialists, advisory services and consultants Table continued Examples of companies (product name) Calmax, USA Cántabra de Turba Coop Ltda, Spain CETAP/Antonio Matos Ltda, Portugal Comercial Projar SA, Spain De Baat BV, Netherlands DIREC-TS, Spain; Earthgro, USA IFM, USA Igene Biotechnology Inc, USA Italoespañola de Correctores SL, Spain Harmony Farm Supply, USA Lombricompuestos de la Sabana, Colombia Louisiana Pacific, USA Megafarma SA de CV, Mexico New Era Farm Service, USA OM Scotts and Sons, USA (Hyponex) Paygro, USA Peaceful Valley, USA (ClandoSan) Planet Natural, USA Prodeasa, Spain Pro-Gro Products Inc, USA Reciorganic Ltda, Colombia RECOMSA Reciclado de Compost SA, Spain Rexius Forest Products, USA Sonoma Composts, USA Turbas GF, Spain ARBICO, USA (Compost Tea, Bio-Dynamic Compost Inoculant) NOCON SA de CV, Mexico ARBICO, USA (Compost Thermometer) Woods End Research Laboratory, USA (Solvita maturity test kit) Aplicaciones Bioquímicas SL, Spain Wrightson Seeds, Australia and New Zealand (BQMulch, BioQure) Dr Antonio Bello and colleagues, CCMA, CSIC, Spain Dr Abraham Gamliel, Institute of Agricultural Engineering, Israel Dr JA Kirkegaard, CSIRO, Australia Dr James Stapleton, University of California, USA Dr J Tello, Dpt Biología, University of Almería, Spain Agrocol Ltda, Colombia Agroshacam SL, Spain Asociación Colombiana de Exortadores de Flores (ASO COLFLORES) Colombia Bio-Integral Resource Center, USA Calmax, USA CIAA Agricultural Research and Consultancy Center, Colombia Comercial Projar SA, Spain Comité Jean Pain, Belgium De Ceuster NV, Sint-Katelijne-Waver, Belgium Demeter Guild, Darmstadt, Germany

81 Products and services Specialists, advisory services and consultants (continued) continued Table continued Examples of companies (product name) École Nationale Supérieure de Technologie, Université Cheikh Anta Diop, Senegal FUNDASES Foundation, Colombia Reciorganic Ltda, Colombia Dr Antonio Bello and colleagues, CCMA, CSIC, Spain Ing. Sergio Trueba Castillo, NOCON SA, Mexico Dr Michael Dann, Penn State University, USA Dr Roberto García Espinosa, Colegio de Postgraduados en Ciencias Agricolas IFÍT, Mexico Ing. Zoraida Gutierrez, Cultivos Miramonte, Colombia Prof Harry Hoitink, Department of Plant Pathology, Ohio State Universiy, USA Dr George Lazarovits, Pest Management Research Centre, Canada Dr Mario Tenuta, Pest Management Research Centre, Canada Dr Frank Louws, North Carolina State University, USA Dr Nahum Marban Mendoza, Universidad Autónoma de Chapingo, Mexico Dr Klaus Merckens, Egyptian Biodynamic Association, Egypt Ing. Marta Pizano, Hortitecnia, Colombia Dr Rodrigo Rodríguez-Kábana, Department of Plant Pathology, Auburn University, USA Dr Yitzhak Spiegel, Agricultural Research Organisation, Israel Dr J Tello, Dpt Biología, University of Almería, Spain Prof Tang Wenhau, China Agricultural University, China Note: Contact information for these companies and specialists is provided in Annex 6. Section 4: Alternative Techniques for Controlling Soil-borne Pests 69

82 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Solarisation Advantages Relatively simple application procedures. Cheaper than MB. Non-toxic treatment; no health or safety problems for users. Registration is not required. Promotes beneficial microorganisms in the soil. Tends to increase soil fertility; increases soluble nitrogen (NO 3, NH 4 ), calcium, magnesium and potassium. Long-term beneficial effects on disease control. Disadvantages Requires time for treatment, with land typically taken out of production for four to seven weeks. Limited to regions with sufficient solar radiation. Does not control all soil-borne pests, so may need to be combined with other techniques. Needs to be adapted to the local crop production systems. Like MB fumigation, it generates plastic waste. Technical description In solarisation treatments, transparent plastic sheets are placed on the soil to trap heat from the sun and raise the soil temperature to levels that kill or suppress pests. The thin sheets are made of UV-resistant polyethylene about 30 to 100 microns thick. Treatment is carried out prior to planting crops and can also be applied as a post-plant treatment in orchards and vineyards. The soil is normally prepared by disking, rototilling or otherwise turning to break up clods. Large rocks, weeds or other debris that may raise or puncture the plastic sheets are removed. The land surface is smoothed so the plastic can rest directly on the soil, since air pockets reduce the heating effect. The sheets are then placed on the soil by hand or machine; several techniques are described in Grinstein and Hetzroni (1991) and Elmore et al (1997). Care must be taken to avoid stretching or tearing the plastic. If holes or tears do occur they must be patched with clear plastic tape, otherwise solarisation will not be effective. The sheets may cover an entire field or greenhouse floor or be placed only along the strips or rows where crops will be planted. Sheet edges are sealed with UV-resistant glue or buried and covered with soil. Thermometers can be placed in the soil at specific depths to record soil temperatures during the treatment. Typically, the plastic sheets remain in place for four to seven weeks. Treatment Table Length of solarisation treatment required to kill 90 to 100% of Verticillium dahliae sclerotia at various soil depths in Israel Soil depth (cm) Time to kill 90 to 100% of sclerotia (days) Source: Katan and DeVay 1991.

83 times may be shorter, however, for certain susceptible pests or for crops with very shallow roots. Solarisation of containerised substrates or growth media and closed greenhouses may take only a few days during strong summer heat (Elmore et al 1997). The aim of solarisation is to ensure that soil at the depth below root level reaches at least about 40 C for the required number of days. Many soil pests are killed at temperatures above 33 C, although others require significantly higher temperatures (Elmore et al 1997). In general, good results can be achieved if soil temperatures of 47, 45, 43 and 39 C are achieved at soil depths of 10, 15, 20 and 30 cm, respectively (Katan 1996, 1999). Adequate soil moisture is important for conducting the heat through the soil and to make weed seeds and pathogens vulnerable to heat. At the start of the treatment, the soil should be saturated to at least 70% of field capacity in the upper layers and moist to depths of 60 cm (Elmore et al 1997). If soil moisture drops to less than 50% of field capacity, or if the soil is well drained, it may be necessary to irrigate during the solarisation treatment. Over-watering, however, must be avoided because it cools the soil and reduces the efficacy of solarisation. When removing sheets, care must be taken to ensure that untreated soil does not contaminate treated soil. If laid manually and handled carefully, sheets may be used for more than one season. As noted earlier, there are several major variations of solarisation: Complete cover of the area Plastic sheets are laid in a continuous surface, covering the entire field or greenhouse floor. Edges may be joined with UV-resistant glue or by overlapping and burying the edges. If beds are formed after solarisation, deep tillage must be avoided because it may bring untreated soil to the surface. After solarisation the sheets are removed and crops are planted as normal. Complete cover is recommended where the soil is heavily infested with pathogens, because it is more effective than strip solarisation. Strip solarisation Beds are formed in the soil and plastic sheets are laid along them, forming strips on the field. Wide strips are more effective than narrow strips, because pathogens are not controlled in the uncovered soil between strips. It is recommended that strips be a minimum of 75 cm wide, but beds up to 1.5 m wide are more effective and allow several crop rows to be planted on each bed (Elmore et al 1997). When solarisation has finished, the plastic Table Examples of commercial use of solarisation Crops Greenhouse tomatoes and other vegetables Open-field winter tomatoes Peppers, eggplant, onions Vegetable nurseries, musk melons Greenhouse crops Containerised nursery soil Stakes for supporting plants Orchards of stone fruit, citrus, olives, nuts and avocado Vineyards Examples of countries Southern Italy, Greece, Jordan, Morocco USA (Florida) Israel Mexico, Caribbean, South America Japan USA Morocco USA (California) USA (California) Compiled from: Elmore et al 1997, MBTOC 1998, Katan 1996, Katan 1999, Batchelor 1999 Section 4: Alternative Techniques for Controlling Soil-borne Pests 71

84 Table Nematodes controlled by solarisation in California USA Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 72 Nematodes Criconemella xenoplax Ditylenchus dipsaci Globodera rostochiensis Helicotylenchus digonicus Heterodera schachtii Meloidogyne hapla Meloidogyne javanica Pratylenchus hamatus Pratylenchus penetrans Pratylenchus thornei Pratylenchus vulnus Tylenchulus semipenetrans Xiphinema spp. Common names Ring nematode Stem and bulb nematode Potato cyst nematode Spiral nematode Sugarbeet cyst nematode Northern root knot nematode Javanese root knot nematode Pin nematode Lesion nematode Lesion nematode Lesion nematode Citrus nematode Dagger nematode Source: Elmore et al 1997 Table Fungi and bacteria controlled by solarisation in California USA Fungi Disease caused Crops Didymella lycopersici Didymella stem rot Tomatoes Fusarium oxysporum f.sp.conglutinans Fusarium wilt Cucumbers Fusarium oxysporum f.sp.fragariae Fusarium wilt Strawberries Fusarium oxysporum f.sp.lycopersici Fusarium wilt Tomatoes Plasmodiophora brassicae Club root Cruciferae Phoma terrestris Pink root Onions Phytophthora cinnamomi Phytophthora root rot Many crops Phytophthora lycopersici Corky root Tomatoes Pythium ultimum, Pythium spp. Seed rot or seedling disease Many crops Rhizoctonia solani Seed rot or seedling disease Many crops Sclerotinia minor Drop Lettuce Sclerotium cepivorum White rot Garlic, onions Sclerotium rolfsii Southern blight Many crops Thielaviopsis basicola Black root rot Many crops Verticillium dahliae Verticillium wilt Many crops Bacteria Disease caused Crops Agrobacterium tumefaciens Crown gall Many crops Clavibacter michiganensis Canker Tomatoes Streptomyces scabies Scab Potatoes Source: Elmore et al 1997 may be painted and left on the soil to serve as a mulch. Strip solarisation is generally cheaper than complete cover. It is effective against certain weeds, but long-term control of fungi and nematodes may not be sufficient, because pests in the untreated soil can spread to treated areas. Strip solarisation is not recommended for soil that is heavily infested.

85 Table Weeds controlled by solarisation in California USA Weeds Abutilon theophrasti Amaranthus albus Amaranthus retroflexus Amsinckia douglasiana Avena fatua Brassica nigra Capsella bursa-pastoris Chenopodium album Claytonia perfoliata Convolvulus arvensis (seed) Conyza canadensis Cynodon dactylon (seed) Digitaria sanguinalis Echinochloa crus-galli Eleusine indica Lamium amplexicaule Malva parviflora Orobanche ramosa Oxalis pes-caprae Poa annua Portulaca oleracea Senecio vulgaris Sida spinosa Solanum nigrum Solanum sarrachoides Sonchus oleraceus Sorghum halepense (seed) Stellaria media Trianthema portulacastrum Xanthium strumarium Space solarisation This technique is used in greenhouses to kill pests surviving in crop debris in the structure of a greenhouse. If the greenhouse surface is dusty, it must be washed before the treatment begins, to allow solar radiation to penetrate. The greenhouse is then closed during summer time, so that inside air temperatures reach 60 to 70 C. Equipment such as tomato stakes or canes can also be disinfested in closed greenhouses. Common names Velvetleaf Tumble pigweed Redroot pigweed Fiddleneck Wild oat Black mustard Shepherd s purse Lambsquarters Minerslettuce Field bindweed Horseweed Bermuda grass Large crabgrass Barnyard grass Goose grass Henbit Cheeseweed Branched broomrape Bermuda buttercup Annual bluegrass Purslane Common groundsel Prickly sida Black nightshade Hairy nightshade Sawthistle Johnson grass Common chickweed Horse purslane Common cocklebur Source: Elmore et al 1997 The treatment time for solarisation varies according to the target organisms, soil conditions and temperature. Under Mediterranean conditions, for example, a period of 30 to 40 days between June and September is suitable for solarization for many purposes (Katan 1999). As a general rule, the longer the solarisation period, the deeper the effect in the soil. See Table for examples. The best control of pests is usually achieved in the upper 10 to 30 cm of soil. The efficacy of solarisation can be increased and/or treatment time reduced by using a double layer of plastic or by combining solarisation with one of the following: Section 4: Alternative Techniques for Controlling Soil-borne Pests 73

86 Biological antagonists such as Trichoderma (as used in Jordan, for example). Reduced doses of fumigants such as metam sodium. Certain organic amendments, such as chicken manure or brassica residues, that release volatile compounds and provide a biofumigation treatment. Current uses Solarisation is used commercially for a variety of crops in warm climates. For example, solarisation has been used for more than a decade in California USA for field, vegetable and flower crops and in orchards, vineyards, greenhouses and landscapes (Elmore et al 1997). Other examples are given in Table Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Table Examples of nematodes, weeds and fungi and bacteria that are not controlled effectively by solarisation Nematodes Meloidogyne incognita Monosporascus spp. Weeds Convolvulus arvenis (plant) Cynodon dactylon (plant) Cyperus esculentus Cyperus rotundus Eragrostis sp. Malva niceansis Melilotus alba Sorghum halepense (plant) Common names Southern root knot nematode Sudden wilt of melon Common names Field bindweed (plant) Bermuda grass (plant) Yellow nutsedge Purple nutsedge Lovegrass Bull mallow White sweetclover Johnson grass (plant) Fungi and bacteria Disease caused Crops Fusarium oxysporum f.sp. pini Fusarium wilt Pines Macrophomina phaseolina Charcoal rot Many crops Pseudomonas solanacearum Bacterial wilt Several crops Source: Elmore et al 1997, Strand , Katan 1999 Table Examples of yields from solarisation and MB Crops Country Yields from solarisation Yields from MB Open-field pepper Israel t/ha Similar Open-field eggplant Israel t/ha Similar Greenhouse pepper Israel t/ha Similar Greenhouse tomato Jordan t/ha t/ha Greenhouse cucumber Jordan t/ha t/ha Greenhouse eggplant Jordan 162 t/ha Similar Israel t/ha Similar Greenhouse strawberry Jordan t/ha Similar 74 Compiled from: Katan 1999, Batchelor 1999, Vickers 1995

87 Variations under development Sprayable mulches. Biodegradable covers (mulches or plastic). Double-layer plastic. Wavelength-selective mulch films that are translucent, photo-selective and transmit infrared light. Material inputs Water. Transparent UV resistant polyethylene sheets, normally 40 to 100 microns thick. Thermometers to measure soil temperatures at root depth. For mechanical application: tractor and sheet layer For large areas laid by hand: mechanical trencher Factors required for use Sufficient sunlight hours and daily temperatures to attain necessary soil temperatures. A time period, typically four to seven weeks, when field or greenhouse is not used for crops. Training and know-how. Pests controlled Solarisation can control many soil-borne pests such as fungi, weeds, insects and mites (Katan and DeVay 1991, DeVay et al 1991). In addition, solarisation frequently promotes the growth of beneficial soil microorganisms that reduce populations of soil pests during the growing season. Tables 4.5.3, and give examples of nematodes, fungi, bacteria and weeds controlled by solarisation in California, USA. Some of these results have been verified in other countries, such as Israel, Jordan, Greece and southern Italy (Katan 1996). The technique must be adapted to different climatic regions and cropping systems. Certain pathogens, such as Verticillium fungi and Ditylenchus nematodes, are sensitive to solarisation and are more easily controlled by it. Solarisation controls many annual weeds effectively but does not control perennial weeds that have deeply buried roots or rhizomes, unless the heat penetrates to those levels. In some areas solarisation does not adequately control root-knot nematodes and heat-resistant pests, such as nutsedge weeds and certain fungi. To control these pests, solarisation should be combined with other techniques or used as part of an IPM system. Table gives examples of nematodes, fungi, bacteria and weeds that are not controlled, or are not controlled reliably, by solarisation. Yields and performance Where the technique is applied properly in the appropriate climate, solarisation results in yields similar to those achieved with MB fumigation (see Table 4.5.7). Solarisation leads to changes in the physical and chemical features of soil, often improving the growth and development of plants. It releases soluble nutrients such as nitrogen, calcium, magnesium, potassium and fulvic acid, making them more available to crops (Elmore et al 1997). Other factors affecting use Suitable crops and uses Solarisation is suitable for all horticultural crops, including orchards and vineyards. For perennial crops solarisation can be applied as a post-plant treatment. It can be used in open fields, greenhouses, tunnels, seedbeds and nurseries. Solarisation can also be used to control pests in substrates, containers or cold frames. In these cases, the soil or substrates can be placed in bags or flats covered with transparent plastic or in layers that are Section 4: Alternative Techniques for Controlling Soil-borne Pests 75

88 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide to 22.5 cm wide sandwiched between two sheets of plastic (Elmore et al 1997). The US California Department of Agriculture has approved a protocol for using solarisation to kill nematode and fungal pests in soil and containers used for raising clean nursery stock. The soil temperature must be raised by solarisation to 70 C for at least 30 minutes. Use of solarisation is often limited to production systems that allow a downtime of four to seven weeks for the treatment, unless combined with other treatments. Suitable climates and soil types Solarisation is suitable for many soil types, although water must be applied during treatment in sandy soils. Its use is limited to geographical regions that have sufficient solar radiation to achieve high temperatures in the soil. Highest soil temperatures are attained when days are long, air temperatures are high, skies are clear, and there is no wind (Elmore et al 1997). Clouds and wind diminish the heating effect. Solarisation is most effective in warm, sunny locations. It has also been used successfully in cooler areas during periods of high air temperatures and clear skies. In cooler climates, solarisation of greenhouses, nurseries, seedbeds and containerised soil or substrates is more effective than solarisation of fields (Katan et al 1998). Toxicity and health risks Solarisation treatments do not pose any safety risks to users or local communities. Safety precautions for users Safety measures are not required. No safety training or safety equipment is required. Residues in food and environment Solarisation does not produce undesirable chemical residues in air, water or food. However, plastic waste may remain in soil and the surrounding environment, as is the case with MB fumigation sheets. Phytotoxicity The treatment does not normally produce toxicity problems for crops. Impact on beneficial organisms Many beneficial soil organisms recolonise the soil rapidly after solarisation. Solarised soil frequently becomes more pest-suppressive due to the establishment of fluorescent pseudomonads (Katan 1996). Solarisation shifts the soil population in favour of beneficial organisms and makes it more resistant to pathogens than non-solarised or fumigated soil (Elmore et al 1997). Ozone depletion Solarisation does not use ODS. Global warming and energy consumption Energy is used for production of plastic sheets, any mechanical application used and recycling of plastic, where available. Energy consumption is less than that with MB fumigation. Other environmental considerations Like MB, solarisation sheets generate significant quantities of waste plastic. In a few regions, including parts of Brazil, Italy and Greece, agricultural plastic recycling schemes have been established. Acceptability to markets and consumers Solarisation is very acceptable to markets and consumers, because it is a non-chemical treatment and does not leave undesirable residues in food. Registration and regulatory restrictions Solarisation does not require regulatory approval.

89 Cost considerations Strip solarisation is cheaper than complete cover but less effective. Material costs are lower than for MB. Plastic sheets that are 50 microns thick are generally cheaper than 100-micron sheets, although the thicker sheets may be re-used. Manual application allows re-use of plastic, whereas mechanised application precludes re-use. Labour is about 10 to 20 man-days for manual cover of 1 ha with continuous sheets, about 3 man-days/ha for mechanical application, or about 0.5 man-days/ha for mechanical strip application. The total cost of solarisation is normally less than MB application. Questions to ask when selecting the system Which soil-borne pests need to be controlled? What depth will crop roots grow to? Is the sunlight/temperature sufficient to heat soil to the required temperature and depth? What method will be used to check that soil depths have reached sufficient temperature? Does solarisation need to be combined with another technique to control the full range of soil pests? Does the production system allow sufficient time for treatment? If not, can the system be amended to accommodate the treatment? Can solarisation be combined with another technique to reduce treatment time? What are the costs and benefits of solarising the entire area versus strips? Will the plastic sheets be re-used? What type and thickness of plastic sheets would be cost-effective? What are the costs and profitability of this system compared to other options? Availability Materials are available in many countries. Suppliers of products and services Table provides examples of suppliers of products and services related to solarisation. Please refer to local agricultural suppliers for additional names of manufacturers and suppliers. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Table Examples of suppliers of solarisation products and services Products or services Sheets for solarisation Examples of companies AEP Industries Inc, USA Agrocomponentes SL, Spain Agroplas SA de CV, Mexico Aplicaciones Bioquímicas SL, Spain CETAP/Antonio Matos Ltda, Portugal Comercial Projar SA, Spain Dura Green Marketing, USA LS Horticultura España SA, Spain Plastigómez SA, Ecuador continued Section 4: Alternative Techniques for Controlling Soil-borne Pests 77

90 Table continued Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 78 Products or services Sheets for solarisation (continued) Specialists, advisory services and consultants in solarisation Plastic recycling services or equipment Examples of companies Plastilene SA, Ecuador and Colombia Plastlit Plásticos del Litoral, Ecuador Polyon Inc, Israel Poly West, USA Productos Químicos Andinos, Colombia and Ecuador Solplast, Spain Sotrafa, Spain CCMA, CSIS, Spain DI.VA.P.R.A. Patologia Vegetale, University of Torino, Italy FHIA Foundation for Agricultural Research,Honduras Dr Walid Abu Gharbieh, University of Jordan, Jordan Dr Bassam Bayaa, Aleppo University, Syria Prof Mohamed Besri, Institut Agronomique et Vétérinaire Hassan II, Morocco Dr G Cartia, University of Reggio Calabria, Italy Dr Jean-Pierre Caussanel, Centre de Recherches de Dijon, France Dr Vincent Cebolla, Instituto Valenciano de Investigaciones Agraria, Spain Dr Dan Chellemi, Florida Horticultural Research Laboratory, USDA-ARS, USA Dr Angelo Correnti, ENEA Departimento Innovazione, Italy Prof James DeVay, University of California, USA Dr Clyde Elmore, University of California, USA Dr A Gamliel, Agricultural Research Organization, Israel Dr Raquel Ghini, EMBRAPA/CNPMA, Brazil Prof Ludovica Gullino, University of Torino, Italy Dr Volkmar Hasse, GTZ-Jordanian IPM project, Jordan Dr Barakat Abu Irmalieh, Univeristy of Jordan, Jordan Dr Florencio Jiménez Díaz, INIFAP Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico Prof R Jiménez Díaz, CSIC Córdoba, Spain Prof Jaacov Katan, Hebrew University of Jerusalem, Israel Dr Franco Lamberti, Instituto di Nematologia Agraria CNR, Italy Dr Hülya Pala, Plant Protection Research Institute, Turkey Dr Satish Lodha, Central Arid Zone Research Institute, India Mr C Martin, Agriphyto, France Dr Abdur-Rahman Saghir, NCSR, Lebanon Prof M Satour, Agricultural Institute, Egypt Prof E Tjamos, Agricultural University of Athens, Greece Prof James Stapleton, Kearney Agricultural Center, University of California, USA Kennco RECOMSA Reciclado de Compost SA, Spain Contact local government authorities to find out if there is a local recycling scheme for plastic waste Note: Contact information for these suppliers and specialists are provided in Annex 6.

91 4.6 Steam treatments Advantages Modern techniques are highly effective. Controls the same range of pests as MB. Does not entail the use of toxic chemicals. Treatment time is rapid compared to MB and other alternatives. Crops may be planted immediately after treatment. Some steam methods are easy to use. Negative pressure and fink systems can provide deep soil treatments. Disadvantages Significant initial capital investment, unless a boiler is hired. Consumes more energy than does MB. Requires a supply of water at treatment time. Some older methods are complicated to apply. High-temperature methods (above 82 C) can produce phytotoxicity. Sterilization method (90 to 100 C) creates a biological desert in the soil, like MB. Boilers can be difficult to transport on poor roads. Technical description When the soil temperature is raised to at least 65 C for 30 minutes, heat kills many pathogenic fungi, bacteria, nematodes and weed seeds. Steam treatments are traditionally conducted at temperatures between 60 and 100 C. Soils may be sterilised at high temperatures for short periods (a few minutes at 90 to 100 C) or pasteurised at lower temperatures for longer periods (such as 30 minutes at 72 C). This lower temperature controls most pests but does not eliminate all the organisms in the soil. Steam treatments are fast and there is no waiting time because crops can be planted as soon as the soil has cooled. The soil is prepared for steam treatment by removing clods and covering with material such as insulated sheets. A conventional boiler or steam generator provides the steam. Steam can be released onto the soil surface, ploughed or raked into the soil, but it is normally more effective to inject steam into the soil or to pull steam through the soil by negative pressure. The efficacy of the treatment requires an application method that distributes steam evenly through the soil and carries it to sufficient depths to kill pests. As with other techniques, steam treatments require know-how and attention to detail during application. Steam may be applied alone or mixed with air. Aerated steam has the advantage of being cooler (e.g. 72 C), moving faster and more uniformly through soil and, in some cases, reducing energy consumption. Available boilers range in capacity from about 65 kg/hour to at least 4,500 kg/hour for treating larger areas. Large areas are treated in batches, one plot at at time. Boilers can be fixed in one place or moved from one area to another. In some countries, companies provide mobile steam boilers as a contracted service for many greenhouses. The following are among the many varieties of steam treatment: Sheet steaming The traditional method of steaming is to cover the soil with sheets, seal the edges and release steam under the sheets for about 4 to 8 hours. This method provides a shallow treatment and is very inefficient in energy use. It does not control pests reliably unless carried out with great care and skill. Section 4: Alternative Techniques for Controlling Soil-borne Pests 79

92 Table Comparison of steam techniques for greenhouses Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 80 Treatment Negative Factor pressure Sheet Hood Fink Equipment Drainpipes buried Sheets laid on soil Hood pressed Vertical pipes in in soil; sheets laid surface onto soil surface soil; pipe grid and on surface sheets on surface Treatment depth cm cm 15 cm 50 cm Treatment time 3-5 hours 4-8 hours <1 hour 5-6 hours Energy/area 115 MJ/m MJ/m 2 46 MJ/m MJ/m 2 Energy efficiency Efficient Highly inefficient Efficient Efficient Labour for treat- 75 hours hours 5-10 hours 75 hours ing area of 1,000 m 2 Comments Fixed system for Variable results unless Rapid, shallow Portable system deep soil treatment applied with skill treatment for deep soil and attention to detail treatment Table Examples of commercially used steam treatments Crops Greenhouse tomato Greenhouse lettuce, celery Greenhouse vegetables Cut flowers and ornamentals Various protected crops Used substrates, pots, trays etc. Plant materials Negative pressure method This fixed system is generally preferable to older techniques because it is more energyefficient and disperses steam more evenly in soil. Perforated drain pipes are laid in the soil at intervals of 1.6 to 3.2 m, depending on the density of the soil structure. Normally, a drainage pit is constructed for collecting excess water. A cover is placed on the soil surface and steam is introduced beneath it. A simple fan is placed at the end of the drainpipe network to create a negative pressure, pulling the steam down through the soil and raising the temperature to 70 to 80 C, even at the deepest levels. Steam is applied for Countries UK UK USA, many other countries Colombia, Italy, Netherlands, UK, USA and many other countries Germany Belgium, Netherlands, Norway Norway Compiled from: MBTOC 1998, Barel 1999, Ketzis 1992, Gullino 1992, Ellis 1991, USDA 1997 one to two hours at a high rate and then reduced to a low rate for several hours. The treatment typically takes four to five hours. Fink method This method uses principles similar to those of the negative pressure system. Rubber pipes are inserted vertically into the soil and a pipe grid is laid on the surface, under sheets. A fan creates suction in the pipes, allowing steam to penetrate to about 50 cm depth. The Fink method takes about five to six hours and has similar advantages to the negative pressure system. In addition, it can be moved around to treat other plots.

93 Hood or metal box method In this method a shallow, inverted aluminum or steel box is pressed into the soil surface. The large box may cover an area of approximately 6 x 2.5 m. Steam is applied inside the box for 20 to 25 minutes, so that the top 20 to 25 cm of soil reaches about 80 C. In automated systems, a winch moves the machine along the bed, and the box is raised and lowered by pneumatics. This type of system may be operated by one labourer and can treat field areas of up to 2,000 m 2 in 10 hours. It is more energy efficient but provides a shallow treatment suitable only for certain crops and pests. Steam ploughs Various forms of steam ploughs are available. The NIAE mobile grid, for example, has a transverse leading blade, which breaks up the soil across the width of the grid, enabling steam to spread sideways from perforated pipes. The motion of soil over the transverse blade encourages steam penetration, forming a bow wave that opens up the soil vertically. The NIAE grid moves at 7 to 8 m per hour, treating a width of about 1.7 m and a depth of 40 to 45 cm of soil. Steam chambers Airtight chambers or steam boxes provide rapid steam treatments for soil, substrates and agricultural equipment. In some nurseries, soil is placed in containers and forklifted into steam boxes for treatment. In a few countries mobile steam chambers trucks fitted with boilers and large air-tight chambers serve many greenhouses in a locality. Substrates are removed from plastic wraps or containers and placed inside the chamber. Steam from the mounted boiler is introduced into the sealed chamber, until the substrates have reached the required temperature. After cooling, the substrates are reused in the greenhouse. Negative pressure steam chambers Super-heated steam, up to 160 C, is forced through material in a chamber, and negative pressure sucks out condensed steam. Heating time is very short, approximately five minutes. This system can be used for substrates, peat, pots, trays and certain plants. At present there are about 12 chambers operating in Belgium and the Netherlands, each with the capacity to treat about 2.5 hectares of substrate in 24 hours. A smaller-scale negative pressure chamber is used for nursery equipment, trays and plants in Norway. Table Examples of steam treatments required to kill soil-borne pests Soil-borne pests Nematodes Rhizoctonia solani, Sclerotium and Sclerotinia sclerotiorum Botrytis grey mould Most plant pathogenic fungi and most plant pathogenic bacteria Soil insects Virtually all plant pathogenic bacteria and most plant viruses Most weed seeds Tomato mosaic virus in root debris A few species of resistant weed seeds and resistant plant viruses Lethal soil temperature and duration 49 C for 30 minutes in moist conditions 52 C for 30 minutes in moist conditions 54.5 C for 30 minutes in moist conditions 62 C for 30 minutes in moist conditions C for 30 minutes in moist conditions 71 C for 30 minutes in moist conditions C for 30 minutes in moist conditions 90 C for more than 10 minutes C for 30 minutes in moist conditions Compiled from: Ellis 1991, Agrelek 1995 Section 4: Alternative Techniques for Controlling Soil-borne Pests 81

94 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 82 In general, negative pressure and fink steaming are preferable to traditional sheet steaming, because they disperse steam more evenly in the soil, give better results and use less energy. Hood and chamber methods are also efficient for specialist applications. Older techniques can take soil temperatures too high, sterilising soil and releasing heavy metals and phytotoxic materials. They also give uneven results or fail to reach sufficient depth. Negative pressure methods give better results than traditional sheet methods on clay, peat, loam and sandy soils (Ellis 1991). See Table for a comparison of some greenhouse methods. Current uses Steam is widely used for greenhouses, nurseries, bulk soil, containerised soil and substrates. It is also used in a limited number of small-scale fields. In the Netherlands, up to 10% of cucurbit production utilises negative pressure steaming (De Barro 1995), for example, and in the USA small portable steam generators have been used successfully in greenhouses for more than 20 years (USDA 1997). Table provides other examples of commercial uses. Variations under development Improved versions of steam ploughs. Automated equipment that lifts the top layer of soil and moves it through a steam bed for open field applications. Material inputs Sheet steaming requires: Water. Boiler or steam generator and fuel. Heat resistant pipes to distribute steam over soil surface. Heat resistant insulated sheets to cover soil. Thermocouple to monitor soil temperature. Negative pressure steaming requires: Equipment listed above. Perforated pipes (preferably polypropylene pipes of about 60 mm diameter) buried permanently under the soil. Fan with a capacity of 1,800 m 3 /hour for an area of 2,500 m 2 ; capacity of 1,000 m 3 /hour for an area of 1,000 m 2. Pump and sump. Factors required for use Supply of water at the time of year when steam treatments are carried out. Capital for initial investment. Roads suitable for transporting heavy boiler equipment. Know-how and training. Pests controlled Steam treatments control a wide range of soil-borne pests, including nematodes, fungal pathogens, weeds and insects. Some steam methods control a wider range of pests than MB. It is necessary to select a steam delivery method that will control pests to the required depth. Few organisms can withstand a moist soil temperature of 65 C maintained for ten minutes (Ellis 1991). Nematodes, insects, many fungi, weed seeds and many bacteria are killed at even lower temperatures (Table 4.6.3), but higher temperatures are recommended to deal with heat-tolerant pests and cool patches that occur in soil. Efficacy depends mainly on the soil temperature, treatment duration and application method to provide a thorough distribution of heat in the soil. In the Netherlands, for example, a temperature of 70 C maintained for 30 minutes is generally recommended to control soil-borne pathogens (Runia 1983, Ellis 1991). Lower temperatures could be applied for a longer time or higher temperatures for a shorter time.

95 Yields and performance Where the technique is properly applied, yields are equal to those achieved with MB. Other factors affecting use Suitable crops and uses Steam can be used in greenhouses, seedbeds and small-scale field nurseries, for containerised soil, substrates (e.g. perlite, rockwool, polyurethane foam, rice hulls, compost), nursery tools, pots and surfaces that are contaminated with pathogens. Steam can be economically viable for high value crops such as ornamental bedding plants, potted foliage, flowering house plants, fresh cut flowers and greens, bulbs, container perennials, and greenhouse vegetables (EPA 1997). Steam treatments are particularly suitable for multicropping, because treatment is rapid and waiting periods can be avoided. Suitable climates and soil types Steam can be used in all climates, from cool temperate to tropical. UNIDO has carried out effective demonstrations of steam in regions as diverse as Argentina, China, Guatemala, Syria and Zimbabwe (Castellá 1999). Steam treatments are suitable for clay, loam, sand and substrates. Steam-treating peat is difficult but feasible. Toxicity and health risks Steam is not toxic. The associated heat, however, can pose a risk of burns if handled improperly or if accidents occur, so boilers and operating procedures must meet safety standards. Steam treatments do not pose risks to the health of local communities or farm workers in fields next to the treatment areas. Safety precautions for users Measures need to be taken to prevent users from coming into contact with steam. In addition, safety training and safety equipment are needed for the use of boilers. Residues in food and environment Steaming to high temperatures (about 100 C) can lead to undesirable levels of ammonia and nitrite in soils that have been fertilised or have a high content of organic matter. This problem can be avoided by keeping the soil temperature below 82 C. Phytotoxicity When certain soils are heated to about 100 C, manganese, ammonia and nitrites may be released. Excess manganese can produce problems of phototoxicity in crops, but this problem is normally avoided by keeping treatment temperatures below 82 C. Impact on beneficial organisms Like MB, steam has a significant negative impact on beneficial organisms in the soil. If soil is heated to 100 C, virtually all organisms are killed, creating a biological desert. The impact is reduced if lower temperatures are used and the soil is pasteurised rather than sterilised. Ozone depletion Steam is not an ODS. Global warming and energy consumption Steam generation normally consumes more energy than does MB fumigation. Negative pressure systems are generally considered energy-efficient steaming methods, because they use less than half the energy of traditional sheet steaming (Ellis 1991). In some cases it is possible to use alternative fuel sources, such as methane from landfills, biogas, hot water from electric power stations, sawdust, wind or geothermal vents (EPA 1997, Davis 1994). Other environmental considerations Some steam techniques use significant amounts of water, making them unsuitable for areas with limited water supplies. Section 4: Alternative Techniques for Controlling Soil-borne Pests 83

96 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 84 Acceptability to markets and consumers Steam is very acceptable to supermarkets, purchasing companies and consumers, because it is a non-chemical treatment and does not leave pesticide residues in food. Registration and regulatory restrictions Registration and regulatory approval are not required for steam treatments for soil. However, boilers must meet all necessary safety standards. Cost considerations The initial capital cost of steam is substantially higher than the cost of MB. Depending on capacity, a boiler may cost from about US$ 4,000 to more than US$ 100,000. A boiler with an output of 90 kg steam per hour costs approximately US$ 5,700 in the USA. A portable electric boiler with the same capacity costs about US$ 4,665 in South Africa. In the USA, a farm that usually fumigates 12 hectares per year can recover the capital costs of steam in 1 year (Quarles 1997). Where investment capital is not available, growers could consider hiring a boiler instead of purchasing it (Ellis 1991). Operating costs of steam can be similar to MB in northern Europe (De Barro 1995), while the operating costs for steam treatments in the USA are less than the typical cost of US$ 1,000 to 1,500 per acre for MB fumigation (Quarles 1997). In the Netherlands, the annual cost of using steam in greenhouses is in the same range as the cost of MB fumigation (De Barro 1995). Labour costs for manual steaming are generally higher than the costs of MB, while labour for automated steaming is often cheaper. Labour time for treating 1000 m 2 can vary from 5 to 80 hours, depending on the steaming method. Questions to ask when selecting the system What area needs to be treated? What soil depth does the treatment need to reach? What is the best method for distributing steam evenly and to the necessary depth? What boiler size is required? In the long-term, is it cost-effective to hire a boiler or to buy one? Is a fixed or movable steam system more appropriate? How will measurements be taken to assure that sufficient temperature has been reached at the required depth? What are the costs and benefits of different methods of steam treatment? What are the costs and profitability of this system compared to other options? Availability Boilers are manufactured in many countries, so it is normally possible to purchase one locally. The materials for negative pressure and Fink systems are simple and readily available, while steam ploughs and hood systems involve specialist equipment and are not yet widely available. Suppliers of products and services Examples of suppliers of steam equipment and services are given in Table See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources.

97 Table Examples of suppliers of products and services for steam and heat treatments Products and services Steam boilers, steam generators, related equipment, and steam treatment services Steam / heat chambers for sterilising substrates, agricultural equipment and plants etc. Specialists, advisory services and consultants in steam treatments Examples of companies Bast Co, Germany Bel Import 2000 SL, Spain Boverhuis Boilers BV, Netherlands Celli SpA, Italy Colmáquinas SA, Colombia Comercial Projar SA, Spain Crone Asme Boilers, Netherlands De Ceuster, Belgium Egedal, Denmark Exportserre-Excoserre SRL, Italy Hans Dieter Siefert GmbH, Germany HKB, Netherlands Ingauna Vapore, Italy Marshall Fowler, South Africa Marten Barel Beheer BV, Netherlands Metalúrgica Manllenense SA, Spain Saskatoon Boiler Manufacturing, Canada (boilers only) Sioux Steam Cleaner Corp, USA Steamist Company, USA Thermeta, Netherlands Tur-Net, Netherlands Aquanomics International, New Zealand De Ceuster BV, Belgium Marten Barel BV, Netherlands Ole Myhrene, Norway Thermo Lignum, Austria, Germany and UK Tur-Net, Netherlands Quarantine Technologies International, New Zealand Dr Bill Brodie, Department of Plant Pathology, Cornell University, USA Agrelek, South Africa Aquanomics International, New Zealand CCMA, CSIC, Madrid, Spain Comercial Projar SA, Spain DVL Advisory Office, Netherlands FUSADES Foundation for Economic and Social Development, El Salvador Marten Barel Beheer BV, Netherlands PBG Research Station for Floriculture and Glasshouse Vegetables, Netherlands Quarantine Technologies International, New Zealand Sino Dutch Training and Demonstration Centre, China Thermo Lignum, Austria, Germany and UK Weyerhaeuser Corporation, USA Dr Leigh Molys, Department of Agriculture, Canada continued Section 4: Alternative Techniques for Controlling Soil-borne Pests 85

98 Table continued Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Products and services Hot water soil treatments and electric heat soil sterilizers Heat equipment for weed control, including flamers and hot water systems Examples of companies Aqua Heat, USA Gempler s Inc, USA Great Lakes IPM, USA Olson Products Inc, USA Aqua Heat, USA Ben Meadows, USA Flame Engineering Inc, USA Harmony Farm Supply, USA (Red Dragon) Peaceful Valley Farm Supply, USA Planet Natural, USA Waipuna International Ltd, New Zealand and USA (Waipuna System) Note: Contact information for these suppliers and specialists is provided in Annex 6. 86

99 4.7 Substrates entails costs for recycling or disposing of substrate materials. Organic Advantages Often give higher yields than MB. Increase opportunities for extending the growing season and harvesting at times when prices are better. Produce more uniform fruit and vegetables. Non-toxic to farm workers and local communities. Can be adapted to suit a wide variety of economic situations, ranging from lowcapital systems that are simple to use, to capital-intensive systems that require substantial management. Disadvantages Water-based hydroponic systems require specialist know-how and may fail if not well managed. Water-based systems generate nutrient solution waste which must be managed or cleaned and re-circulated. Inert substrates need to be disposed of at the end of their useful life, and this Technical description Substrates replace soil by providing a clean medium for plants to grow in. Substrate materials can be taken from a wide variety of sources, if the sources are free from pests and pathogens and free from contaminants that could cause crop toxicity or undesirable food residues. Substrates also need to have pore spaces and other characteristics that allow good retention and movement of nutrients, water and air for the plant roots. Where necessary, several materials can be mixed together to create a substrate with optimum characteristics. If the raw materials are not free from pathogens, they can be treated with steam (see Section 4.6) or solarised (see Section 4.5) prior to use. Substrate materials differ in their physical properties, providing different conditions for root growth, transport of water, nutrients and air, and consequently for crop yield. Substrates with low water-holding capacity need frequent watering. The acidity/alkalinity, salt content and other characteristics of the chosen substrate materials need to suit the Table Characteristics of various substrate materials Decomposition substrates Bulk density Water-holding Air Electrical rate (carbon: (weight) capacity content conductivity nitrogen) Bagasse Bark Coir dust Peat sphagnum Rice hulls Sawdust Inert substrates Sand Vermiculite Key: + undesirable, +++ desirable characteristics Adapted from: Johnson (undated), Kipp & Weaver 2000 Section 4: Alternative Techniques for Controlling Soil-borne Pests 87

100 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 88 requirements of specific crops. For example, strawberries grow very successfully on peat, while some flowers and vegetables grow successfully on coconut fibre. The PBG Research Station for Floriculture and Glasshouse Vegetables in the Netherlands has published a handbook on the physical and chemical characteristics of a variety of substrate materials and suitable crops (Kipp et al 1999, 2000). In general, desirable characteristics include low weight, high water-holding capacity, medium porosity and low cation exchange capacity. A low carbon:nitrogen decomposition rate is desirable for hydroponic production. See Table for information on the characteristics of various substrate materials. For detailed technical information on the characteristics of a range of substrate materials refer to Kipp et al (1999, 2000). Substrate materials can be divided into two broad types: Organic substrates Organic substrates are made from agricultural products or dead organic matter. Many are biologically active and have a high carbon: nitrogen ratio, which means they are broken down during the growing season by microorganisms, changing texture, ph and nutrients. Organic substrates are not suited for hydroponic systems, but they are very effective for crop production when used like potting mixes in bags, pots, trenches or other containers. The biologically active nature of organic substrates helps to provide a buffer if pathogens are accidentally introduced into the system. Some organic substrates strongly suppress pathogens. For others, biological controls can be added to give pest-suppressive properties. Sources of organic substrate materials include the following: Coconut plant fibres or coir. Composted plant residues or agricultural waste. Rice hulls (waste from grain milling). Bagasse or sugarcane waste. Peat and past substitutes. Reed fibres. Pine bark, sawdust and other waste from the forest industry. Straw bales. Mushroom industry waste. Some of these materials must be mixed with others to achieve successful substrate textures and characteristics. Bagasse, for example, has low porosity and high water-holding capacity, which would lead to poor aeration for plant roots if used alone. Sawdust also has a high water-holding capacity that can lead to poor aeration. Rice hulls, in contrast, have low water-holding capacity and high pore space, so plants would be vulnerable to water stress if rice hulls were used alone (Johnson undated). Each of these materials, however, can be useful as one component of a substrate mixture. Certain materials need to be treated before use. Coconut, for example, sometimes has a high salt content which makes it unsuitable for strawberries unless it is washed before use. Inert substrates Inert substrates are made from materials such as rocks or polyurethane. They do not have the ability to suppress the spread of pathogens introduced accidentally, so they demand a high degree of sanitation and hygiene. Some growers now add biological controls such as Trichoderma (see Section 4.2) to inert substrates to give them pest-suppressive properties. Inert substrates normally require a high degree of water/nutrient management, because the plant gets all its nutrients from the delivered nutrient solution. When selecting materials, weight is a consideration because heavy materials like gravel or sand are more difficult for growers to move around. Lightweight materials, such as pumice or vermiculite, can be moved more readily.

101 Table Comparison of two substrate systems Potting mix system: coconut Hydroponic system: rockwool substrate in plastic bags substrate in controlled greenhouse Substrate Local waste material placed in Manufactured substrate wrapped in farm-made plastic bags plastic sleeves Equipment Plastic tunnel, plastic cover on floor Greenhouse, plastic cover on floor (or (to separate substrate bags from soil), tables to hold substrate and nutrient irrigation pipes; meters for ph solution), irrigation system, water and electrical conductivity management equipment, meters for measuring ph and electrical conductivity Infrastructure Minimal High level of management and control Capital Low capital input High capital input Know-how Some know-how required Substantial know-how required; technical consultant visits regularly to advise on nutrients and other aspects of the system Water system Conventional drip irrigation pipes System for circulating, cleaning and recirculating water Soil pest control Biological controls may be added Strict hygiene and application of during growing via irrigation system once a month fungicides if necessary or suppressive season biological controls Examples of inert substrates include the following: Expanded clay granules Glass wool, rock wool (fibres of melted basalt, limestone, granite and silica). Gravel (small stones or pebbles). Perlite, pumice (volcanic rock). Vermiculite (expanded mica). Recycled polyurethane foam. Slag from steel mill operations. In practice, substrates are used with a wide variety of irrigation systems, from simple punctured hoses to fully computerised, recirculated systems. Substrate systems can be divided into two broad groupings listed below. (See Table for a comparison.) Potting mixes Substrates are used in a similar way to containerised soil or potting mix, held in some form of container, such as bags, buckets, pots, lined beds (with wood, concrete or brick sides), lined trenches in the soil, plastic sleeves, hand-made tubes laid along the greenhouse floor, or other simple devices. To stop soil pests from migrating into the substrate, a barrier or space is needed to separate the drainage holes of the container from the soil below. Examples of barriers include a plastic sheet or thick layer of drainage gravel. As with soil in pots or bags, water is applied to the top surface of the substrates or via irrigation pipes or sprinklers. Any excess water drains from the base of the containers and is not re-circulated. Some but not all of these systems require a high capital investment and substantial knowhow. They can give high yields with low risk, provided that suitable substrate materials are used. Their use is increasingly common in greenhouses and tunnels around the world. They are also used in open fields in a few cases. Section 4: Alternative Techniques for Controlling Soil-borne Pests 89

102 Table Examples of commercial use of substrates Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 90 Crop Protected tomatoes on various substrate materials Protected cucurbits on various substrates Protected vegetables on various substrates Strawberries normally on peat or peat + coconut Protected cut flowers Carnations on scoria beds Roses on coconut and other substrates Nursery crops (vegetables and fruit) Tobacco seedlings Bananas Various protected crops on gravel substrates Water-based and hydroponic systems Hydroponic means water working, and in these systems water is the principal constituent. Substrates such as rock wool or polyurethane foam provide support for the plants, retaining nutrients and water. Hygiene, water circulation and nutrient levels are critical parts of the system and need to be carefully controlled. Hydroponic systems generally require significant capital investment, infrastructure and a high degree of know-how and management. The Nutrient Flow Technique (NFT) is one type of hydroponic system in which a shallow depth of nutrient solution is recirculated by pump, through a series of narrow channels where the plants sit. Water-based systems can produce very high yields but have a high risk of failure if not properly managed. They are common in northern Europe and Canada, and are used increasingly in many other countries. It is important to keep substrate systems free from contamination by pathogens. Accidental introduction of pathogens can be avoided by using the following techniques: Countries Spain, Belgium, Germany, Netherlands, UK Belgium, Egypt, Jordan, Lebanon, Morocco, Netherlands, UK, USA Belgium, Canada, France, Germany, Morocco, Netherlands, UK, USA (Florida) Belgium, Indonesia, Malaysia, Netherlands, UK Brazil, Canada, China, Colombia, Belgium, Netherlands, USA Australia Australia, Belgium, Denmark, Netherlands Brazil, Canada, Chile, Germany, Israel, Mexico, Morocco, Netherlands, Spain, Switzerland, UK, USA, Zimbabwe Brazil, Argentina, USA Canary Islands South Africa and some other countries in Africa Compiled from: MBTOC 1998, MHSPE 1997, Environment Australia 1998, Gyldenkaerne 1997, Batchelor 1999, Peter van Luijk BV 1999, Nuyten 1999, Benoit and Ceustermans 1996, Benoit 1999 Good standards of hygiene, such as cleaning equipment after use. Use of pathogen-free plant materials. Placing substrates in many separate containers (e.g. pots or bags) rather than one continuous container, to prevent the spread of pathogens if contamination occurs. Use of clean water (e.g. filtering water prior to use). After use, organic substrate materials can be disposed of by spreading them on fields to improve soil texture. Some organic and inert substrates can be re-used after being cleaned with steam or solarisation. Substrates can be solarised in bags or flats covered with transparent plastic or in layers 7.5 to 22.5 cm wide sandwiched between two sheets of plastic (Elmore et al 1997). In sunny areas (e.g., warmer parts of California) substrates inside black plastic sleeves can reach 70 C, achieving effective solarisation within a week. Current uses Substrates are extensively used in greenhouses and nursery operations in many countries

103 and to a limited extent for open-field production. They are used for numerous crops, including tomatoes, strawberries, cut flowers, melons, cucurbits, bananas, nursery-grown vegetable transplants and tobacco seedlings (MBTOC 1998). Table provides examples of commercial uses. Variations under development Additional source materials from waste materials. Improved disease-suppressive substrates. New mixtures, giving optimal textures for specific crops. Material inputs Inputs for potting mix types of substrates include the following: Substrate material. Additional inputs for water-based and hydroponic systems are as follows: Container for water bed beneath the substrates. Equipment for managing water supply. If water is re-circulated, equipment for cleaning water. Meters for measuring ph and electrical conductivity. Specialist technical know-how. Factors required for use For low cost systems: Local source of cheap substrate (e.g. clean waste material). Know-how and training. Containers such as plastic-lined trenches, beds, plastic bags, plastic tubes or pots for holding substrate and providing a barrier between the substrates and soil floor. Normal irrigation or manual watering. Clean planting materials (especially if inert substrates are used). For hydroponic systems: Secure supply of water to prevent plants from drying out. Attention to detail and very regular monitoring and management. Substantial technical know-how and training. Table Examples of yields from substrates Crop/country Type of substrate Yields from substrates Yields from MB Strawberry, Italy Natural substrate 4.8 kg/m 2 3 kg/m 2 Protected strawberry, Peat 9 kg/m 2 4 kg/m 2 Netherlands double cropping Protected strawberry, Peat or peat + coconut 22,000 kg/ha 15,000 kg/ha Scotland double-cropping Protected tomato, Sawdust + Trichoderma 50 kg/m 2 Similar yields New Zealand Tomato, Belgium Polyurethane foam or 52 kg/m 2 normally kg/m 2 rock wool double cropping Melon, Netherlands Rock wool 20 kg/m 2 10 kg/m 2 double cropping Protected cucumber, Rock wool 68 kg/m kg/m 2 Netherlands triple cropping Section 4: Alternative Techniques for Controlling Soil-borne Pests Compiled from: De Barro 1995, Vickers 1995, Benoit and Ceustermans 1991, Benoit and Ceustermans 1995, Batchelor

104 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 92 Pests controlled Clean substrates are normally free from soilborne pests such as nematodes, pathogens, weeds and insects, thus avoiding the need to control these pests. Control with clean substrates is generally comparable to control achieved with MB. Some natural substrates (e.g. composted pine bark) also have the ability to suppress certain pathogens, reducing risks if pathogens are introduced accidentally by irrigation water or plant material. Yields and performance Yields from substrates are equal to, and frequently higher than production with MB (see Table 4.7.4), particularly because substrates give a longer cropping period and allow double cropping or multi-cropping (Benoit & Ceustermans 1991, 1995; Nordic Council 1993; Gyldenkaerne et al 1997). In addition, substrates allow more control of harvest time (such as earlier harvests) to meet more profitable market windows. Yields are generally similar for the different types of inert substrates. Yields from organic substrates can be more variable if they are used in systems with unsophisticated management. Other factors affecting use Suitable crops and uses Substrates can be adapted for all types of horticultural crops. They are most appropriate for greenhouses, seedbeds and nursery containers, but they are also used to a limited extent for open field production. However, different substrates with different physical and chemical characteristics are required for different types of crops and uses. Substrates are very suitable for double cropping and multi-cropping. Suitable climates and soil types Substrates are used in virtually all climates, from the arctic to the tropics. They are suitable for all types of soils, because the soil itself becomes irrelevant. Toxicity and health risks Farm workers can normally handle substrates safely because they are composed of nontoxic materials. However, if substrate materials form dusts or fine particles, normal precautions should be taken to prevent exposure to the dust while the substrate is being laid out or moved. Safety precautions for users Substrates do not normally require special safety precautions, so safety training and safety equipment are generally not required. However, substrates that form dusts require safety equipment to protect the lungs and respiratory system. In some cases protective clothing is desirable when the substrates are lifted at the end of the season. Residues in food and environment Substrates do not pose safety risks to consumers of fruits and vegetables, provided that the quality and composition of substrates are controlled to ensure that potentially toxic or phytotoxic contaminants are excluded from the raw materials. Phytotoxicity Commercially available substrate materials are not phytotoxic to crops. If farmers make their own substrates from locally available materials, they must avoid raw materials that may cause phytotoxicity problems. Impact on beneficial organisms Substrates sit on top of the soil and are separated from it, so they do not have a direct effect on beneficial organisms in the soil. If disease-suppressive substrates are spread on fields after their useful life, however, they contribute beneficial organisms to the soil. Substrates are compatible with the use of beneficial organisms, and many substrate systems benefit from the addition of biological control agents.

105 Ozone depleting potential Substrates are not ODS. Global warming and energy consumption Substrates in themselves do not have globalwarming potential, but like MB they require energy for extraction, manufacture and transport. Some preliminary energy balances have been carried out to compare MB and some types of substrates. Available information indicates that rock wool and polyurethane foam substrates consume much more energy in their manufacture than pumice and peat. Natural substrates composed of waste materials consume the least energy, although this depends on the distance that the substance is transported. In general, the energy required for production using substrates is less than MB when measured per kg of produce. Low-technology systems have minimal use of energy, while high-tech systems such as heated glasshouses can use substantial amounts of energy. Nevertheless, in northern Europe, for example, greenhouses that use MB and soil normally use more energy for heating than greenhouses that use substrates. Other environmental considerations Substrates made from rock (e.g. mica, volcanic pumice) and peat are extracted from the natural environment and can damage natural habitats such as wetlands.to avoid this problem, it is desirable to consider other source materials for substrates. Water consumption in substrate systems depends largely on the design and management of the system. Tomatoes grown in border soil or substrate systems can use the same amount of water (Gyldenkaerne et al 1997). The wastewater can easily lead to water pollution, if it is allowed to leach into watercourses. Where there is concern about run-off, organic substrates are preferable to inert ones because they retain more nutrient solution (Hardgrave and Harrimann 1995). Various systems, such as those that clean and re-circulate water, reduce water consumption and minimise any pollution. After use, organic substrates can often be disposed of by spreading them on fields, helping to improve soil texture. Inert substrates normally create problems with solid waste, although collection and recycling schemes exist for certain substrates (e.g. rock wool) in certain countries. Most inert substrates can be cleaned and re-used. For example, polyurethane foam is treated with steam in portable lorry-mounted chambers in Belgium and can be re-used for 10 to 15 years. Acceptability to markets and consumers Substrates are normally highly acceptable to supermarkets, purchasing companies and consumers. Supermarkets often prefer crop production on substrates, because the products are generally more consistent and uniform in quality. Registration and regulatory restrictions Normally, substrates do not have to be approved and registered in the same fashion as pesticides. Some countries have codes of practice for ensuring quality control of substrate materials. Such controls are highly desirable to ensure that substrates perform consistently and are free from pathogens, weed seeds and undesirable contaminants. Cost considerations In the case of hyrdoponic and recirculated systems, initial capital costs are generally high or very high, compared to MB. In Denmark, the payback period for a capital-intensive system is normally two to four years (Gyldenkærne et al 1997). Material costs are normally more expensive than MB, except where cheap or waste materials are used as substrates. Labour costs may be slightly higher. Overall, substrate systems are often more profitable than systems using MB, Section 4: Alternative Techniques for Controlling Soil-borne Pests 93

106 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 94 because they allow longer production periods or multi-cropping. In the Netherlands, substrate systems increased farmers incomes by 10 to 20% on average over previous MB systems (MHSPE 1997). In Florida (USA), the cost of producing greenhouse hydroponic vegetables ranges from US$ 2 to 15 per square foot, but the costs are offset by higher production (up to 10 times higher than field-grown produce) (Hochmuth 1999). Questions to ask when selecting the system What are the necessary substrate characteristics for the selected crops or seedlings? What sources of clean, pathogen-free, cheap, waste materials are available locally? Are the substrates free from contaminants that may cause undesirable residues or phytotoxicity? What systems can be used for quality control? What are the cheapest options for vessels or containers to hold the substrates? Table Examples of suppliers of products and services for substrates Products and services Organic substrate materials, e.g.coconut, coconut fibre, composted bark, peat, peat substitutes, stabilised composts and disease-suppressive substrates What types of watering systems are appropriate? What methods are available to monitor and control the water quality and nutrients (ph and electrical conductivity)? What local sources of know-how are available? What is the payback period for a lowcost system versus a more capitalintensive system? What are the costs and profitability of this system compared to other options? Availability Manufactured substrate materials are available in many countries. Waste materials that can be used as substrates are available in all countries. Suppliers of products and services Examples of suppliers of substrate products and services are given in Table See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Examples of companies (product name) Abonos Naturales Hnos Aguado SL, Spain A-M Corporation, Korea (Cocovita) Aplicaciones Bioquímicas SL, Spain Arrow Ecology Ltd, Israel Asthor Agricola Mediterranean SA, Spain BioComp Inc, USA Berger Peat Moss, Canada Cántabra de Turba Coop Ltda, Spain CETAP/Antonio Matos Ltda, Portugal Coco Hits, Spain Comercial Projar SA, Spain Compañia Argentina Holandesa SA, Argentina Compo, Belgium (Cocovita) Cosago Ltda, Colombia De Baat BV, Netherlands DIREC-TS, Spain continued

107 Table continued Examples of companies (product name) Durstons, UK (Composted Bark, Earth Friendly Peat Substitutes, Coconut- Multi-Purpose) Dutch Plantin, Netherlands Earthgro, USA Eucatex Agro Ltda, Brazil (Plantmax, Rendmax) Fabricaciones Vignolles, Spain Floragard GmbH, Germany (Floragard) Floratorf Produckte, Spain Francisco Domingo SL, Spain Hollyland New-Tech Dev Co Ltd, China (Cocopress) Industrias Químicas Sicosa SA, Spain Inferco SL, Spain Italoespañola de Correctores SL, Spain Jiffy Products, Colombia José Maria Pérez Ortega, Spain Klasmann-Deilmann, Germany (Klasmann) Lombricultura Técnica Mexicana, Mexico Louisiana Pacific, USA Melcourt Industries Ltd, UK (Sylvafibre, Potting Bark) Neudorff GmbH, Germany (Kokohum) Nico Haasnoot, Netherlands OM Scotts and Sons, USA (Hyponex) Paygro Co, USA Peter van Luijk bv, Netherlands (Cocopress) Pindstrup Mosebrug SAE, Spain and Scandinavia Prodeasa, Spain Pro-Gro Products Inc, USA Reciorganic Ltda, Colombia Rexius Forest Products, USA Sonoma Composts, USA Southern Importers, USA (Southland) Torfstreuverband GmbH, Germany Intertoresa AG, Germany (Toresa) Turbas GF, Spain Turco Silvestro e Figli SnC, Italy See also Table for companies producing composts; some composts may have the correct composition for substrates Agglorex SA, Belgium (Aggrofoam) Aislantes Minerales SA de CV, Mexico CIA Ibérica de Paneles Sintéticos SA, Spain Cosago Ltda, Colombia, Ecuador Eucatex Agro Ltda, Brazil Grodan, Netherlands, Spain and France (Grodan) Grodania AS, Denmark (Grodan) Guohua Soilless Cultivation Tech Co Ltd, China Hortiplan, Belgium (Rockwool) Morse Growers Supplies, Canada Nordflex AB, Sweden (Recfoam) Peter van Luijk BV, Netherlands (Oxygrow, perlite, pumice, Oasis) Prodeasa, SpainRecticel, France, Germany, Netherlands, Belgium, UK (Recfoam) Rockwool International AS, Denmark (Rockwool) Torfstreuverband GmbH, Germany Compañia Argentina Holandesa SA, Argentina Asthor Agricola Mediterranean SA, Spain Products and services Organic substrate materials, e.g., coconut, coconut fibre, composted bark, peat, peat substitutes, stabilised composts and disease-suppressive substrates (continued) Inert substrates, e.g., polyurethane foam, rock fibre, pumice, vermiculite, perlite Section 4: Alternative Techniques for Controlling Soil-borne Pests 95 continued

108 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Products and services Sleeves, bags, trays and other containers for holding substrates Specialists, advisory services and consultants Collection and/or recycling of inert substrates Table continued Examples of companies (product name) Fabricaciones Vignolles, Spain Francisco Domingo SL, Spain HerkuPlast-Kubern GmbH, Germany and Netherlands (Quick Pot) Hollyland New-Tech Dev Co Ltd, China (Jiffy) Hortiplan, Belgium Jiffy Products, Colombia Panth Produkter AB, Sweden (Starpot, Panth Seedling Tray) Peter van Luijk BV, Netherlands (Jiffy, Peval) Plásticos Solanas SL, Spain Poliex SA, Spain Polygal Plastic Industries Ltd, Israel (Polygal Plant Beds) Transplant Systems, Australia and New Zealand Agricultural Demonstration Centre, China Asthor Agricola Mediterranean SA, Spain Breda Experimental Garden, Netherlands Canadian Climatrol Systems, Canada Comercial Projar SA, Spain Compañía Española de Tabaco SA, Spain Danish Institute of Agricultural Science, Denmark DLV Horticultural Advisory Service, Netherlands European Vegetable R&D Centre, Belgium FUSADES Foundation for Economic and Social Development, El Salvador Harrow Research Centre, Agriculture and Agri-Food Canada HortiTecnia, Colombia INTA Famailla, Túcúman, Argentina (tobacco float systems) Lombricultura Técnica Mexicana, Mexico National Research Centre for Strawberries, Belgium Pacific Agriculture Research Centre, Canada PBG Research Station for Floriculture and Glasshouse Vegetables, Netherlands Peter van Luijk BV, Netherlands PTG Glasshouse Crop Research Station, Netherlands Reciorganica Ltda, Colombia SIDHOC Sino Dutch Horticultural Training and Demonstration Centre, China Technisches Bericht Forschungsanstalt Geisenheim Gemüsebau, Germany Vegetable Research and Information Center, University of California, Davis, USA VLACO, Belgium Dr Antonio Bello, CCMA, CSIC, Spain (float tray systems) Ing. R Sanz, CCMA, CSIC, Spain (float tray systems) Ing. I Blanco, CETARSA, Cáceres, Spain (tobacco) Dr Bob Hochmuth, Institute of Food and Agricultural Sciences, University of Florida, USA Prof Keigo Minami, ESALQ, University of São Paulo, Brazil Mr Henk Nuyten consultant, Netherlands Dr Tom Papadopoulos, Greenhouse and Processing Crops Research Centre, Canada Prof Rolf Röber, Institut für Zierpflanzenbau, Germany Also refer to the list of experts on composts and soil amendments in Table Rockwool-Industries, Denmark (Rockwool) 96 Note: Contact information for these suppliers and specialists is provided in Annex 6.

109 5 Control of Pests in Commodities and Structures Types of commodities and structures MB has been in widespread use as a fumigant for stored grains and import/export commodities for more than 50 years because of its high toxicity to a wide range of pests, good penetration of products and rapid action. The commodities and structures that are fumigated with MB can be divided into three main groups (refer to Figure 1.1): a) Durable products Durables are commodities with low moisture content that, in the absence of pest attack, can be safely stored for long periods. They include foods such as grains, pulses, nuts, dried fruits, herbs, spices, dried medicinal plants and beverage crops along with nonfoods such as tobacco and seeds for planting. They also include logs, sawn timber, wood products, cane and bamboo ware, craft products, museum artifacts, items of historical significance, packaging materials and wooden pallets. Many durable products are stored and traded globally without the need for MB fumigation, but MB is used in a number of situations for controlling stored product pests and quarantine pests. Fumigations are carried out in storage and transport areas such as grain stores, warehouses, docksides and harbours, making use of enclosures such as fumigation sheets, silos, freight containers, railway box cars, ship holds, barges and, in some cases, fixed chambers. b) Perishable commodities Perishables are fresh commodities that generally decay quickly unless they are stored in conditions such as cool storage that prolong their shelf-life. They include fresh fruit, fresh vegetables, cut flowers and ornamental plants. Many of these commodities are traded internationally without the need for fumigation, but MB is required in a number of cases for the control of quarantine pests. Fumigations are carried out in fumigation chambers or under fumigation sheets at places such as specialised farms, packhouses, ports and airports. MB fumigations are carried out either in the country of origin before export or in the importing country if products are found to contain quarantine pests. c) Structures Structures include entire buildings and portions of buildings such as food processing facilities, flour mills, feed mills, storage facilities and warehouses. This group also includes transport vehicles such as ship holds, aircraft and freight containers. MB is sometimes used for controlling stored product pests, wood-destroying organisms, rodents or quarantine pests in such structures, particularly when a rapid full-site treatment is needed. Pests in durable commodities Pest control for durable products is necessary to prevent insects from eating or damaging commodities with a resultant loss of product or reduction in market value. In some cases, it is only necessary to manage and suppress pests to levels that do not cause significant damage. In other cases, it is necessary to disinfest commodities to entirely eliminate pests to meet commercial demands for products that are pest-free or to meet official preshipment requirements. Disinfestation is also Section 5: Control of Pests in Commodities and Structures 97

110 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide required for officially controlled quarantine pests to reduce the risk of introducing or spreading pest species to geographical regions where they are not established. According to MBTOC, MB plays a relatively small but significant role in the disinfestation and protection of durables. This use adds up to an estimated 13% of worldwide MB consumption or around 19% in developing countries, making durables the second largest use of MB after soil fumigation. MB s rapid action and reliability have led to its continued use as the treatment of choice in several specialised situations: Rapid disinfestation of bulk grain to meet commercial, phytosanitary (plant health) or quarantine requirements at the point of import or export. Quarantine treatments against specific pests, particularly khapra beetle, the house longhorn beetle and various snails. Table 5.1 Principal pests of cereal grains and similar durable commodities Common Name Dried bean beetle Flour mite Cowpea beetle Cowpea beetle Groundnut borer Rice moth Rust-red grain beetle Tropical warehouse moth Tobacco moth Mediterranean flour moth Broad horned flour beetle Booklice, psocids European grain moth Yellow spider beetle Saw-toothed grain beetle Indian meal moth White-marked spider beetle Australian spider beetle Lesser grain borer Granary weevil Rice weevil Maize weevil Angoumois grain moth Drug store beetle Yellow mealworm Cadelle Rust red flour beetle Confused flour beetle Khapra beetle Mexican bean beetle Scientific Name Acanthoscelides obtectus Acarus siro Callosobruchus chinensis Callosobruchus maculatus Caryedon serratus Corcyra cephalonica Cryptolestes ferrugineus Ephestia cautella Ephestia elutella Ephestia kuehniella Gnatocerus cornutus Liposcelis spp. Nemapogon granellus Niptus hololeucus Oryzaephilus surinamensis Plodia interpunctella Ptinus fur Ptinus tectus Rhyzopertha dominica Sitophilus granarius Sitophilus oryzae Sitophilus zeamais Sitotroga cerealella Stegobium paniceum Tenebrio molitor Tenebroides mauretanicus Tribolium castaneum Tribolium confusum Trogoderma granarium Zabrotes subfasciatus 98 Key: - major pest Source: MBTOC 1998, Banks 1999

111 Table 5.2 Examples of quarantine pests found on perishable commodities Common name Scientific name or family Common commodities Mexican fruit fly Anastrepha ludens (Lw.) Citrus, other tropical and subtropical fruits Caribbean fruit fly Anastrepha suspensa (Loew) Tropical and sub-tropical fruits Mediterranean fruit Ceratitis capitata (Wied.) Deciduous, sub-tropical and fly tropical fruits Melon fly Bactrocera cucurbitae (Coq.) Cucurbits, tomato, many other fleshy fruits Oriental fruit fly Bactrocera dorsalis (Hendel) Most fleshy fruits or vegetables Queensland Bactrocera tryoni (Froggatt) Deciduous, sub-tropical and fruit fly tropical fruits European Cherry Rhagoletis cerasi (L.) Cherry, Lonicera spp. fruit fly Cherry fruit fly Rhagoletis cingulata (Lw.) Cherry, Prunus spp. Apple maggot fly Rhagoletis pomonella (Walsh) Apple, blueberry Mealy bugs Pseudococcidae Fruit, cut flowers, nursery plants Codling moth Cydia pomonella (L.) Apple, pear, peach, Prunus spp. Mango seed weevil Stemochaetus mangiferae (Fab.) Mango Red-legged earth Halotydeus destructor (Tucker) Leafy vegetables mite Thrips Thysanoptera spp. Leafy vegetables, fruit and cut flowers Aphids Aphididae Leafy vegetables, cut flowers Mites Many species Fruit, vegetables, cut flowers Scale insects Hemiptera Nursery plants, fruit Disinfestation of stacks of bagged grain, particularly in Africa, including food aid at the point of import. Protection and disinfestation of dried vine fruit, some other dried fruit and nuts in storage and prior to sale. Although the use of MB to control pests in stored grains has largely been replaced by other techniques in developed countries, the practice is still widely used for this purpose in a number of developing countries. Most of the target pests of durables are insects and, to a lesser extent, mites. Certain commodities have other target pests, such as fungi in unsawn timber and nematodes in seeds for planting. MB is sometimes specified as a quarantine treatment for ticks and snails Sources: Based on Paull and Armstrong 1994, with additions from Batchelor 1999b that occur as incidental contaminants of durable foods or timber. Table 5.1 provides a list of the principal pests of cereal grains and similar durable commodities. Pests in perishable commodities Fresh fruit, fresh vegetables and cut flowers can carry a wide range of pests, such as fruit flies and mites, and many of these are the subject of quarantine restrictions for import/export commodities (Table 5.2). MB treatments to kill pests in perishable commodities are estimated to account for about 9% of MB consumption worldwide (MBTOC 1998). Treatments for controlling quarantine pests have to be approved by the quarantine authorities of importing countries for individ- Section 5: Control of Pests in Commodities and Structures 99

112 Table 5.3 Examples of pests fumigated with MB in structures Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 100 Type of structure Food production and storage facilities, e.g., food processing plants, mills, warehouses Non-food facilities, e.g., museums Wood within structures, e.g., dwellings, commercial premises, historical buildings, museums ual commodity/pest combinations. This normally requires scientific data to demonstrate that the treatment is virtually 100% effective in killing the target quarantine pest, as well as a process of bilateral negotiations. Historically the process of gaining approval for quarantine treatments for perishables has been very slow, taking from 3 years to well over 10 years. Pressure from companies and governments to phase out QPS uses of MB is likely to speed up the approval process in some areas. Quarantine issues are discussed in detail in the reports of MBTOC (1998) and TEAP (1999). Pest groups Stored product insects Beetles Cockroaches Mites Psocids Rodents Silverfish Stored product insects Cigarette beetles Clothes moths Cockroaches Dermestid beetles Drugstore beetles Rodents Cigarette beetles Clothes moths Dermestid beetles Drugstore beetles Drywood termites Furniture beetles Long horned beetles Powder post beetles Wood boring beetles Pests in structures Pests that infest durable commodities often become established in the fabric of buildings or structures where food is stored. Wooddestroying insects can also infest the wooden beams and wooden parts of buildings. Table 5.3 lists major pest groups that are the targets of MB fumigation in structures. MBTOC estimates that these uses account for about 3% of MB use worldwide (MBTOC 1998). Overview of alternatives A wide variety of measures can be incorporated into an integrated system to disinfest and protect commodities and structures from damage by pests (MBTOC 1998). The following major techniques are described in Section 6: IPM and preventive measures. Cold treatments and aeration. Contact insecticides. Controlled and modified atmospheres. Heat treatments. Inert dusts. Source: Adapted from MBTOC 1998 Phosphine and other fumigants.

113 Table 5.4 Effective techniques for pest suppression and pest elimination (disinfestation) in commodities and structures Techniques Pest Suppression Pest Elimination IPM Effective for suppressing pests; IPM does not provide disinfestation but can used increasingly for durable reduce the need for disinfestation treatments commodities and structures in all types of commodities and structures Cold treatments Effective for stored grains, other Certain treatments are effective for artifacts, and aeration durable products or structures historical items, high value durable where cold air is readily available commodities, and perishable commodities such as citrus and temperate fruit Contact insecticides Effective for stored grains, other Where registered, dichlorvos is effective for and other pesticides durable products, wood products bulk grain; pesticides can be effective for and some structures certain pests in logs, wooden pallets, timber, wood in buildings and aircraft Controlled and Effective for grain and durables Specific treatments can be effective for modified stored for long periods disinfesting stored products, artifacts and atmospheres perishable commodities Heat treatments Effective for some mills and Specific treatments can be effective for food processing facilities grains, logs, timber, tobacco and many durable commodities; and for quarantine treatments in perishable products such as mango, grapefruit, tomato and bell peppers Inert dusts Effective in assisting with pest Not effective management in stored grain and structures Phosphine and Effective for durable commodities Phosphine is effective for bagged and bulk other fumigants and diverse uses generally grains, in-transit ship treatments where used for disinfestation permitted, logs and a wide variety of other durable commodities; it is not generally suitable for perishable commodities. Sulphuryl fluoride is effective for non-food items and structures where registered. All techniques listed above can suppress pests, but some can also be applied to provide disinfestation in certain commodities, allowing them to meet commercial, preshipment and quarantine requirements for pest-free products. Table 5.4 provides an overview of the types of commodities and structures for which alternative techniques can be effective. None of the techniques, however, can be used for all of the applications for which MB is used. Each alternative has different advantages and disadvantages and must be selected Compiled from: MBTOC 1998, TEAP 1999 for the appropriate commodity or structure and circumstances. Section 6 covers the advantages, limitations and suitability of alternatives for different situations and climates. Commercially available alternatives Many alternatives have been developed to the commercial level. Some techniques are used by a small number of enterprises or in a few countries, while others, such as phosphine, have widespread adoption. Examples of alternatives used for grain and other stored products are given in Table 5.5, for Section 5: Control of Pests in Commodities and Structures 101

114 Table 5.5 Examples of alternatives used for durable commodities Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 102 Examples of countries where Durable commodities Treatments alternatives used commercially Stored grains, pulses, Phosphine Germany, Philippines, Thailand, UK, oilseeds Zimbabwe and many other developed and developing countries Carbon dioxide Australia, Indonesia, Philippines, Vietnam In-transit carbon dioxide Australia In-transit phosphine Europe, USA Phosphine mixed with carbon dioxide or nitrogen Australia, Cyprus and Germany Nitrogen Australia, Germany Gas-flushed retail packs Thailand Hermetic storage Cyprus, Israel, Philippines Heat treatment Australia (prototype) Cold treatments Mediterranean, USA Freezing Europe (for premium grains) Inert dusts Australia, Canada, Germany Other food products, e.g., coffee, cocoa beans, Phosphine Used in many countries black pepper, dried fruits, Nitrogen and low temperature Australia most types of nuts, coconut Carbon dioxide and pressure France, Germany products, pet foods Carbon dioxide Australia (commercial trials) Tobacco Phosphine Zimbabwe, Philippines and many other countries Steam conditioning Many countries Methoprene Used in some countries Wood and wooden items Nitrogen or carbon dioxide Germany Kiln drying, heat treatments UK, Denmark, Germany, Austria, USA Phosphine Routine use in some countries Sulphuryl fluoride, Routine use in some countries Borate or bifluorides Germany, USA Artifacts, museum items Heat treatment with Austria, Germany, UK controlled humidity Heat treatment Denmark Nitrogen Germany Compiled from: MBTOC 1997, Prospect 1997, GTZ 1998, USDA-APHIS 1993, Batchelor 1999a perishable commodities in Table 5.6, and for structures in Table 5.7. These examples are intended to illustrate the diversity of techniques available, but it is important to note that each technique is suitable for different and specific situations. For example, a slow-acting nitrogen treatment is not suitable for a situation where a rapid treatment is required. Likewise, cold treatments cannot be used for cold-sensitive commodities that could be damaged by cold. Uses without alternatives There is a limited number of commodities and uses for which MB alternatives have not

115 Table 5.6 Examples of quarantine treatments approved for perishable commodities Treatment Cold treatments Heat treatments Certified pest-free zones or pest-free periods Systems approach Pre-shipment inspection and certification Inspection on arrival Physical removal of pests Controlled atmospheres Pesticides, fumigants, aerosols Combination treatments Approved quarantine applications Apples from Australia, Chile, Ecuador, France, Israel, Italy, Jordan, South Africa and Zimbabwe to USA Cherries from Argentina, Chile and Mexico to USA Grapes from Chile to Japan Grapes from Brazil, Colombia, Dominican Republic, Ecuador, India and South Africa to USA Citrus from Australia, Florida (USA), Israel, South Africa, Spain, Swaziland and Taiwan to Japan Mangoes from Australia, Philippines, Taiwan and Thailand to Japan Papaya from Hawaii to Japan Tomato, bell pepper, zucchini, eggplant, squash, mango, pineapple, papaya and mountain papaya to USA Orange, grapefruit, clementine, mango from Mexico to USA Mountain papaya from Chile to USA Citrus, papaya, lychee, from Hawaii to mainland USA Papaya from Belize to USA Mango from Taiwan to USA Ear corn to USA Orchids, plants and cuttings to USA Chrysanthemum cuttings to USA Plant materials unable to tolerate MB fumigation to USA Banana roots for propagation to USA Many bulbs and tubers to USA Narcissus bulbs to Japan Melons from a region of China and from the Netherlands to Japan Squash, tomatoes, green pepper, eggplant from Tasmania (Australia) to Japan Cucurbits to Japan and USA Nectarines from USA to New Zealand Immature banana to Japan Some avocado exports Citrus from Florida to Japan Certain cut flowers from Netherlands and Colombia to Japan Apples from Chile and New Zealand to USA Garlic from Italy and Spain to USA Nectarines from New Zealand to Australia Green vegetables to many countries Small batches of seeds for propagation to USA Root crops are accepted by many countries if all soil is removed Hand removal of certain pests from cut flowers to USA Propagative plant materials unable to tolerate MB fumigation to USA Apples from Canada to California Cut flowers from New Zealand to Japan Asparagus to Japan Cut flowers from Thailand and Hawaii to Japan Bulbs to Japan Tomatoes from Australia to New Zealand Propagative plant material to USA Certain ornamental plants to USA Soapy water and wax coating for cherimoya and limes from Chile to USA Warm soapy water and brushing for durian and other large fruit to USA Vapor heat and cold treatment for litchi from China and Taiwan to Japan Pressure water spray and insecticide for certain cut flowers to USA Hand removal and pesticide for certain ornamental plants, Christmas trees and propagative plant materials to USA Heat treatment + removal of pulp from seeds for propagation to USA Compiled from: MBTOC 1998, USDA-APHIS 1998 Section 5: Control of Pests in Commodities and Structures 103

116 Table 5.7 Examples of alternative techniques used for structures Treatments Heat treatments Heat treatments + IPM Phosphine + carbon dioxide + heat Sulphuryl fluoride Intensive monitoring + IPM Cold treatment (freeze-out) Structures Historic buildings and mills in Scandinavia Food processing facilities and mills in Canada, USA Food processing facilities and mills in USA Wooden constructions, domestic buildings and railcars in USA Food warehouses in Hawaii, USA, UK Food facilities in Canada. Compiled from: Mueller 1998, GTZ 1998, MBTOC 1998, Batchelor 1999a Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 104 been identified. MBTOC recently reviewed alternatives and failed to identify existing alternatives for the following quarantine and pre-shipment uses of MB for durable commodities and structures (MBTOC 1998, TEAP 1999): Disinfestation of fresh walnuts for immediate sale. Disinfestation of fresh chestnuts. Disinfestation of oak logs with oak wilt fungus. Elimination of seed-borne nematodes in alfalfa and some other seeds for planting. Control of organophosphate resistant mites in traditional cheese stores. Mills and food processing facilities where IPM systems have not been implemented successfully. Some cases of aircraft disinfestation. Worldwide, these uses are unlikely to exceed 50 tonnes of MB per year in total (MBTOC 1998). For perishable commodities, MBTOC failed to identify approved quarantine treatments to replace MB in the following commodities and situations: Apples potentially infested with codling moth and exported from New Zealand and USA to Japan. Stonefruit (peaches, plums, cherries, apricots, nectarines) potentially infested with codling moth and exported to countries free from codling moth. Grapes potentially infested with Brevipalpis chilensis mites exported from Chile to the USA. Grape exports from USA to countries that require MB fumigation. Berryfruit (strawberry, raspberry, blueberry and blackberry) exports from countries such as Australia, Brazil, Canada, Colombia, Israel, New Zealand, South Africa, USA and Zimbabwe. Root crop exports (carrot, cassava, garlic, ginger, onion, potato, sweet potato, taro and yam) where infested with quarantine pests. While viable alternatives are not available for the above uses today, it should be noted that MBTOC (1994, 1998) has identified many potentially effective alternatives that will require additional research and development for application to these specific commodities and pests. Identifying suitable alternatives The identification of a technique appropriate for a specific situation can be complex, because it requires consideration of a wide range of technical, economic, market, regulatory, safety, environmental and organisational factors (see also Section 2). The process may be simplified by following the five steps outlined below:

117 1. Develop a thorough understanding of the pest problems by identifying the pests and learning about their life stages, habits, preferences and the factors that keep them from thriving. 2. Be clear about the market and regulatory requirements for pest control. What degree of pest control is needed? Will pest suppression suffice or is virtual elimination of pests necessary? What practices could be introduced to prevent pest populations from building up and to reduce the frequency of disinfestation treatments? 3. List the techniques that would be effective in controlling the pests in your commodity/structure. Initially, focus solely on technical issues and be sure to make a full list of all possible options. You could start by making a list of all pests that affect the commodity or structure. For each pest, identify all the remedial treatments and preventive practices that would control each pest to a satisfactory level. Then use the list to identify the different combinations of techniques that could control the full range of pests you will encounter. Annex 4 provides template tables to guide you through these steps. 4. Evaluate the suitability of each technical option for your situation. For each option, list the technical requirements, advantages and disadvantages, and consider the relevant issues, such as staff requirements, logistics, equipment and materials, costs, regulatory requirements and safety and environmental issues. (Refer to Section 2 for a brief discussion of these issues.) You may find it useful to summarise the information in a table format, as shown in Annex 4. Specific questions relating to your commodity and situation can include the following: Which pest species and life stages need to be controlled? What degree of pest control is required? What are the habits and preferences of these pests? Which factors favour or discourage their presence, stage development and reproduction? Where and when is each pest species vulnerable? Which procedures and treatments are technically capable of controlling the pests? What steps can be taken to prevent the entry of pests, prevent the build-up of pest populations, and reduce the need for disinfestation treatments? How much time is available for carrying out treatments? Where time is a problem, can commodities be managed differently to allow more time for treatments to be carried out? For example, can treatments be carried out at an earlier stage of storage and handling, or while in transit? Which treatments can the commodity or structure safely withstand without damage or effects on commercial quality? Would residues or other effects present a problem for companies that purchase the products? Which treatments do pesticide safety authorities already permit? Which treatments do not need to be registered? What safety measures need to be taken to protect staff, local communities and the environment? Which treatments and practices will allow staff continuous access to commodities and working areas? What facilities, equipment and staff skills are currently available? What changes in equipment, materials and staff skills would be required by the alternatives? What changes in management and working procedures would be necessary? Section 5: Control of Pests in Commodities and Structures 105

118 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide What activities or steps would have to be carried out to introduce each alternative? What are the capital and set-up costs, operating costs, profitability and payback period for each alternative system? How can the alternatives be adapted and improved to better suit local circumstances? 5. Develop a plan. Once you have chosen the most promising techniques, identify the main steps and activities that adoption of the technique(s) will require. Try to talk with specialists and suppliers to find ways to adapt systems to your needs, to make change feasible, to improve efficacy and to reduce costs. For assistance, refer to the information in Sections 6.1 through 6.7, consult the specialists and suppliers listed toward the end of each Section and the reading material listed in the corresponding section of Annex 7. See Annex 6 for an alphabetical listing of supplier names and contact information. 106

119 6 Alternative Techniques for Controlling Pests in Commodities and Structures 6.1 IPM and preventive measures In order to replace a particular use of MB, it is often necessary to combine several different alternatives in IPM or Integrated Commodity Management (ICM). In most situations with stored products and structures, it is possible to avoid or minimise pest infestation so that clean up with MB is not needed. This type of pest management is not just a replacement for MB but often avoids the need for MB or other remedial treatments. The term IPM is used to describe diverse combinations of treatments and practices to control pests. Development of an IPM system starts with the identification of existing and potential pests and an understanding of the causes of their presence, the factors that allow them to thrive, and their vulnerabilities. Prevention is a major component of IPM and involves activities such as the removal of pest refuges, regular cleaning of storage areas, and use of physical barriers to prevent pests from entering products. Products and structures are monitored regularly for insects, and action is taken if an action threshold is exceeded. The threshold notion involves determining the level of pest activity that can be tolerated without significant product loss or damage. Such a threshold is based on the amount of economic damage that can be tolerated as well as the size and life stage of the populations of pests detailed informaiton about IPM approaches for stored products can be found in Subramanyam and Hagstrum The components of an IPM system will vary greatly from one situation to another, because the system and practices are tailored to a specific location. Some IPM systems require constant maintenance in order to succeed, and occasional full-site or curative treatments may be required to supplement IPM systems. An IPM system for grain stored in bulk or bags, for example, may include cleaning, pest detection procedures, insecticide sprays, stock rotation and control of the storage environment. IPM requires knowledge about the interactions between stored products, the storage environment and the insects associated with the products. It requires significantly more know-how than does MB use, and substantial effort needs to be put into training technicians and commodity managers. Pest management for durables and structures Three important components of pest management for stored products include prevention, monitoring and control (Mueller 1998). a) Prevention For an IPM programme to succeed, the largest proportion of time and effort (about 75%) should go into the tasks of preventing pests from entering storage areas and products, where possible, and preventing them from thriving and accumulating. These aims require changes in commodity management practices, adaptations to the physical environment of storage areas, and the introduction of measures to ensure high levels of cleanliness. Typical prevention activities include the following: Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 107

120 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 108 Changing farm practices, where possible, so that products are kept in clean conditions as soon as they are harvested. Using physical barriers (e.g., insect-proof storage containers, insect screens on windows and openings) to prevent insects from entering structures or gaining access to products. Removing articles and altering storage areas to eliminate crevices and places that could provide refuge for pests, both inside and outside the storage facility. Drawing up a work programme for frequent cleaning (including sweeping and vacuuming) of all parts of the storage premises, to assure that they are free from food residues and debris that attract insects and rodents. Maintaining a 45-cm (18-inch) gap between stored products and interior walls, to assist cleaning. Keeping outside areas clean of food residues that might attract pests. Cleaning all empty commodity receptacles before re-filling, so that no insects remain. Establishing procedures to verify that new batches of products are free from pests and only clean products are brought into stores. Such procedures would include inspecting incoming products and packaging materials for pests and placing contaminated products into separate holding areas until they have been disinfested. Keeping products cool and/or aerated, where feasible. Keeping moisture levels low. b) Monitoring About 20% of the time and effort of an IPM system involves monitoring for pests and carrying out inspections to ensure that prevention practices are properly implemented. Diligent monitoring allows for early action when pests are found. Common activities include the following: Using effectively designed insect and rodent traps with correct pheromone or bait for attracting target pests. Having the correct number (density) and placement of traps. Inspecting batches visually. Examining samples of incoming products and stored batches of products. Using records to identify old stock, since pest outbreaks often start from pallets of old products that have not been rotated or monitored. Maintaining records and rotating stock. Checking moisture, temperature and other conditions that favour or discourage pests. Inspecting premises regularly to ensure that cleaning has been done thoroughly. c) Control If prevention and monitoring are carried out effectively,then less than 5% of time and effort will go into treatments to eliminate pest infestations. Curative treatments become necessary if pest populations become established, often an indication that prevention and monitoring have not been thorough. In contrast to the approach outlined above, enterprises generally put most effort into disinfestation treatments and put little effort into prevention and monitoring. MBTOC points out that many MB alternatives are not direct replacements for MB; rather they are measures designed to avoid the need for MB (MBTOC 1998). Preventive measures for perishable commodities For perishable commodities, some measures can be introduced in the field and after harvest to avoid the need for MB fumigation or other quarantine treatments. This is an

121 Table Examples of pest-free zones that are accepted instead of quarantine treatments Perishable commodities Countries Quarantine pests Capsicum, aubergine Exports from Tasmania Tobacco blue mold (eggplant) and tomatoes (Australia) to Japan (Peronospora tabacina), Mediterranean fruit fly (Ceratitis capitata), Queensland fruit fly (Bactrocera tryoni) Melons Exports from Hsingchang Melon fly (Bactrocera cucurbitae Uighur Autonomous Region Coq.) in China to Japan Strawberries, grapes, melons, Exports from the Netherlands Mediterranean fruit fly tomatoes, peppers, to Japan (Ceratitis capitata) cucumbers, aubergine and squash Grapes, kiwifruit and other Exports from Chile to Japan Mediterranean fruit fly (Ceratitis products capitata) advantage, because MB and other treatments can reduce the shelf life and market quality of perishable commodities. Examples include: a) Inspection and certification In some circumstances, it is feasible to establish a system for inspecting and certifying that products are free from target pests before they are exported. For example, Japanese quarantine officials inspect cut flowers in the Netherlands and Colombia prior to shipment; this reduces the need for inspection and disinfestation treatments on arrival in Japan. Inspection is labour intensive and needs to be carried out by personnel who are well trained and accepted as competent and independent by the importing country. Inspection may become simpler in the future with the development of automatic equipment to scan products and detect pests. For example, chemical sensors may be designed to detect or smell specific compounds emitted by pests. b) Pest-free zones Some countries have certain geographic regions that are free from quarantine pests of concern, even though the pest is established Compiled from: MBTOC 1998 (See Riherd et al 1994 for further examples.) in other parts of the country (Shannon 1994). Where regions can be proven and certified as pest-free zones, products can be exported from them without a quarantine treatment. A substantial amount of scientific survey data is required to demonstrate that an area is free from the target pest. In addition, regulatory measures are required to keep the area pest-free, and on-going surveillance must be carried out. Pest-free zones have been established in a number of countries, including Australia, China, the Netherlands and Chile. Further examples of approved pest-free zones can be found in Table and in Riherd et al (1994). c) Systems approach For certain commodities and pests it is feasible to set up procedures on farms and after harvest to ensure that many small steps eliminate quarantine pests. Examples of measures include the following: Planting commodities that are not the preferred host of the quarantine pest (Armstrong 1994a). Harvesting when the commodity is not susceptible to attack by the pest. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 109

122 Table Examples of combined alternative treatments for commodities and structures Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 110 Commodities or structures Treatments Countries Durable commodities and structures Grains for export IPM + nitrogen treatment Australia Food processing facilities Phosphine + carbon dioxide + heat USA Approved quarantine treatments for perishable commodities Cherimoya and limes Soapy water + wax coating on fruit Exports from Chile to USA Cut flowers (robust types) Pressured water spray + insecticide Exports from various countries to USA Durian and other large fruit Warm soapy water + brushing Exports from various countries to USA Litchi fruit Vapour heat + cold treatment Exports from China and Taiwan to Japan Ornamental plants (certain Removal of pests by hand + Exports from various countypes), Christmas trees and pesticide treatment tries to USA propagative materials Seeds for propagation Heat treatment + removal of pulp Exports from various countries to USA Harvesting when the pest is not active. Covering picked fruit to avoid hitchhiker pests. The systems approach for achieving quarantine security has been described by Jang and Moffitt (1994) and includes the following steps: Consistent and effective management for reducing pest populations in farm fields. Preventing the commodity from becoming contaminated with pests after harvest and during shipping. Culling in the pack house. Monitoring, inspecting and certifying the critical parts of the system. The systems approach can achieve or even exceed the level of quarantine security required by an importing country (Moffitt 1990, Vail et al 1993). It depends heavily on knowledge of the pest-host biology and life Compiled from: MBTOC 1994, MBTOC 1998, Batchelor 1999a, USDA-APHIS 1998 cycles, well-trained staff and implementation of effective management systems. Among the cases of commercial application (MBTOC 1997, MBTOC 1998), is the export of avocados from Mexico to 19 Northeastern states in the USA. Products protected in this manner are certified free from avocado seed weevil, avocado seed moth, avocado stem weevil, fruit fly and other hitchhiker pests, based on field surveys, trapping, field treatments, field sanitation, host resistance, postharvest safeguards, pack house inspection, fruit culling, shipping only in winter, and inspection on arrival in the importing country (Firko 1995, Miller et al 1995). Other examples of the systems approach for quarantine purposes include citrus exported from Florida USA to Japan and apples exported from USA to Brazil. d) Combined treatments Combined treatments can be very useful in replacing MB for perishable commodities, because they allow several narrow-spectrum

123 Table Examples of specialists, consultants and suppliers of services for IPM and preventive pest management techniques Items Durable commodities and structures Perishable commodities or less effective techniques to attain a cumulative impact equivalent to MB. There are several cases where combined treatments have been used commercially for products and have been approved for quarantine purposes. Examples are given in Table Technical information about alternative techniques is found later in this Section. Specialists and consultants Canadian Grain Commission, Canada Canadian Pest Control Association, Canada Cereal Research Station, Canada CSIRO, Canberra, Australia Cyprus Grain Commission, Cyprus Food Protection Services, USA Fumigation Services and Supply Inc, USA Grainco Australia Ltd, Australia Grainsmith Pty, Australia GTZ, Germany HortResearch Natural Systems Group, New Zealand Insects Limited Inc, USA Natural Resources Institute, UK Rentokil, Germany Pacific Southwest Forest and Range Experiment Station, Forest Service USDA, USA For information and examples of commercial application: Bio-Integral Resource Center, USA Quaker Oats Canada Ltd, Canada Crop & Food Research, New Zealand HortResearch Market Access Group, New Zealand Dr Jack Armstrong and Dr Eric Jang, Tropical Fruit and Vegetable Research Laboratory, USDA, USA Dr Arnold Hara, University of Hawaii, USA Dr Robert Hill, HortResearch, Ruakura, New Zealand Dr Adel Kader, Dr Elizabeth Mitcham, Pomology Dept, University of California, USA Dr Michael Lay-Yee, HortResearch, New Zealand Prof Eugenio López L, Universidad Católica de Valparaiso, Chile Dr Robert Mangan, Subtropical Agriculture Research Laboratory, USDA, USA Dr Lisa Neven and Dr Harold Moffitt, Yakima Agricultural Research Laboratory, USDA, USA Dr Jennifer Sharp, Dr Walter Gould and Dr Guy Hallman, Subtropical Horticulture Research Station, USDA, USA Note: Contact information for these suppliers and specialists is provided in Annex 6. Specialists and suppliers of IPM services Table provides examples of specialists, consultants and suppliers of services related to IPM and preventive practices in pest management. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 111

124 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Cold treatments and aeration Advantages No residues left in food. High consumer acceptance. Safe for workers. Relatively easy to use. Cold storage extends shelf-life. Some cold treatments provide disinfestation. Disadvantages Relatively long treatment times (with some exceptions). Relatively expensive. Consumes energy. Not suitable for products that cannot withstand cold temperatures. Technical description Cold treatments can be used for stored products as part of an IPM system, and can also be used for disinfestation to meet QPS requirements. Below about 10 C insect reproduction ceases and the populations of most pests of durable products slowly decline. Temperatures of -15 C for a few days control most pest species in durable commodities. Temperatures around 0 C kill certain quarantine pests of perishable commodities, particularly fruit fly species. Several cold treatment techniques may be used: Aeration Aeration is used in many temperate regions with the aim of cooling grain soon after harvest to a temperature low enough to prevent the development of major insect species (typically less than 14 C). Aeration is typically used to prevent damage, pest multiplication and reinvasion, and a high mortality of stored product pests can be achieved if grain is kept below 5 C for at least four months (MBTOC 1994). Ambient cold air such as cool, dry night air is fed into the stored commodity through an aeration system, typically consisting of ventilation ducts, fans and a control system. Cooling can also be achieved by transferring commodities from one bin to another in cold weather, exposing them to the cold air. Aeration must be combined with other techniques to give control equivalent to repeated fumigations with MB, but of itself can give sufficient insect control to meet the requirements of some markets. Well-controlled aeration and cooling result in negligible grain losses due to insect pests. Refrigerated cooling If cool, dry ambient air is not available for aerating grain, it is feasible to use refrigeration units to chill and dehumidify incoming air, even in humid sub-tropical environments. Many grain silos in the Mediterranean and sub-tropical regions use this technique (MBTOC 1998). Other durable products can be held at refrigeration temperatures (preferably less than 5 C) to delay the development of pests. Cold treatments Cold storage at temperatures down to about 0 C is suitable for long-term protection of certain types of durable products, such as prunes, dried pears, nuts and beverage crops. Commodities can be stored in cold stores and other warehouse facilities equipped for refrigeration. Cold treatments in the range of -1 to +2 C are important quarantine treatments for certain perishable commodities, such as citrus fruit, and a number of different treatment schedules have been approved by quarantine authorities. These vary with the type of fruit, target pest and destination country. Table provides examples of quarantine cold treatment schedules. Cold treatments can

125 only be used for perishable and durable commodities that tolerate cold temperatures without suffering quality damage. Freezer treatments All common stored grain insect pests can be controlled when grain is exposed for 2 weeks to temperatures lower than -18 C (MBTOC 1998). Such freezer treatments are used for the disinfestation of small batches of high value grain, including special seed stocks and organically grown rice. Exposure to -10 C for about 11 hours disinfests dates, for example. This treatment is particularly effective when combined with a brief exposure to 2.8% oxygen or to low pressure, which causes insects to leave the centre of the fruit and become vulnerable to the cold (Donahaye et al 1991, Donahaye et al 1992). While freezer treatments are effective for certain types of durables, they are sometimes only practicable for treating small quantities in batches. Freezing cannot normally be used for perishable commodities, because such commodities have a high moisture content and fragile cell walls that make them vulnerable to severe damage. For quarantine purposes, freezer temperatures are typically required to eliminate pests sufficiently in durable products. In the case of perishable commodities, quarantine treatments are based on higher temperatures, typically -1 C to +2 C, although the exact temperature and duration depends on the susceptibility of the target pest and the commodity s tolerance of cold. Cold temperatures have to be carefully selected to kill target pests while avoiding damage to products, particularly those of tropical origin, which are more sensitive to cold. In some cases it is possible to prevent damage by using two-stage treatments (Houck et al 1990a, Aung et al 1997). Many commodities, such as grain, are poor thermal conductors and provide pests with some protection against the cold, so it is necessary to ensure that cold temperatures are achieved within the commodities, not simply in the air spaces between them. The required treatment times vary greatly according to the following factors: Temperature. Rate at which the commodity conducts the cold. Pest species and pest life stage. A treatment period of between 12 and 24 days at about 0 C is generally required to disinfest perishable commodities of fruit flies, while a 2-week treatment below -18 C is required to disinfest grain of common pests. On the other hand, some cold treatments are considerably faster than this and faster than MB fumigation. For example, a treatment to disinfest dates requires 10.5 hours of exposure to -10 C or only 2.25 hours exposure at -18 C (Donahaye et al 1991). Where feasible, it is desirable to carry out cold treatments as part of the normal cool storage or handling of products. Cold treatments can sometimes be carried out in refrigerated shipping containers while products are in transit to markets. One of the advantages of cold treatments is that staff members have continued access to commodities at all times. This contrasts with MB fumigation, during which staff cannot enter the commodity area for safety reasons. Current uses Diverse types of cold treatments are used commercially for a wide range of products in both warm and cool climates (Table 6.2.1). Cold treatments are used as part of IPM systems for grain in the Mediterranean region, North America, Australia and other areas. Cold treatments are also used where cold storage warehouses are part of a storage system, for example for prunes in the USA and France. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 113

126 Table Examples of commercial use of cool and cold treatments Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 114 Products Stored grains in temperate climates Freeze treatment for disinfestation Cold storage (below 1 C) for long- term protection from pests Cold treatments for disinfestation Cold treatments for quarantine Cold treatments for quarantine Cold treatments for quarantine Grain in silos in the Mediterranean and sub-tropical regions High-value grains for export, e.g., organically grown rice Small volumes of seeds Dehydrated raisins in the USA. prunes and dried pears Museum objects Fresh apple and pear exports to the USA Table grapes exported from Chile to Japan Grapefruit and other citrus fruit exported from many countries to Japan Warehouses or grain stores in countries with low winter temperatures such as Canada Freezer treatments are used for disinfestation of durable commodities in a few cases, such as museum objects, small quantities of seed and high value grain products. Cold treatments are also used as quarantine treatments for perishable commodities, such as citrus and fruit from temperate climates. Material inputs For aeration: ducts, fans and control systems in storage structures. Additional electrical services. Refrigeration treatments require the use of a cool store or cold storage warehouse, or require refrigeration equipment to be fitted to the storage or shipping containers. Freezer treatments require the use of premises with freezer storage, or require freezer equipment to be fitted to storage or shipping containers. Equipment to monitor and control temperatures and in some cases humidity. Know-how and training. Treatments Aeration to slow down insect development Refrigerated aeration to delay insect development Freeze treatment for disinfestation Freeze-outs as structural or space treatments Factors required for use Compiled from: MBTOC 1998 For ambient air aeration: cool or cold ambient air during day or night, with low or moderate humidity. Where disinfestation is required, sufficient time during storage or transportation to allow a treatment to kill all target pests at all life stages. Pests controlled Cool temperatures provide pest management, while freezing temperatures are normally necessary for disinfestation. If grain is held at less than 5 C for several months, most of the immature stages of stored product pests die off, although some adult pests may survive. Cool temperatures (below about C) generally do not kill insects but stop their feeding and reproduction, with a resulting slow decline of most pest populations in durable products. Temperatures of -15 C for a few days control most pests (Chauvin and Vannier 1991, Fields 1992). All stages of Sitophilus granarius, Callosobruchus rodesianus, Ephestia cautella and Ephestia kuehniella are killed at -18 C for

127 5 hours in wheat, maize and soy bean (Dohino et al 1999). Woollen artifacts can be disinfested from clothes moths by exposure to -18 C for a few days (Brokerhof et al 1993). Additional information on the effects of cold treatments on various pest species can be found in Johnson and Valero (1999). In general eggs are more cold-sensitive, while adults and larvae are often more tolerant of cold. Species of tropical origin, such as Sitophilus oryzae, Sitophilus zeamais, Tenebroides mauritanicus and Lasioderma serricorne, tend to be cold sensitive, although some important pests including Cryptolestes spp., bruchids, mites and some Lepidoptera species are very tolerant of cold temperatures (Armitage 1987, Lasseran and Fleurat-Lessard 1991, Fields 1992). The diapausing moth larva is highly resistant to cold, requiring more than 14 days at -10 C or 1 day at -15 C; the adult rusty grain beetle, on the other hand, requires 8 weeks at a grain temperature of -5 C, 6 weeks at a grain temperature of -10 C, or 2 weeks at a grain temperature of -15 C (Banks and Fields 1995). Some species of insects have the ability to acclimatise to cold and may become tolerant to temperatures that would normally be lethal. Rapid cooling may be necessary to prevent such adaptation. Other factors affecting use Product quality Cool and cold treatments for stored grain give grain quality that is the same as or better than MB fumigation. Cool storage maintains the quality and extends the shelf life of perishable products. Cold temperatures down to about 0 C can be tolerated by a number of perishable commodities, but in some cases a pre-conditioning treatment, such as exposure to 15 C, is necessary to prevent damage to products. Table Comparison of aeration, cold treatments and freezer treatments Aeration Cold treatments Freezer treatments Temperatures < 5-15 C -1 to +2 C -15 to -19 C Degree of Pest Disinfestation or pest Disinfestation pest control suppression suppression Pests Stored product Quarantine pests (mainly Stored product pests pests fruit flies) in perishable and quarantine pests commodities; stored product pests in durables Suitable products Stored grains, Certain perishable High-value durable pulses, oilseeds commodities such as products such as citrus, carambola, organically grown kiwifruit and grapes; rice, special seeds certain stored products, and museum objects such as prunes and nuts Equipment Ventilation ducts, Refrigerated warehouse Freezer chamber or fans and control or storage area; refrig- warehouse; storage system erated shipping container area for frozen foods or meat Treatment time Cool For perishable products, From 2 hours to 2 temperature about days. weeks, depending on maintained For durables, cool the pest, treatment continuously temperature maintained temperature and rate throughout the throughout the storage at which cold is storage period period conducted through the treated objects Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 115

128 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 116 Temperatures around 0 C can be tolerated by many durable products but leads to quality degradation in others. For example, longterm storage can lead to crystallisation of fruit sugars in processed sultanas. A disinfestation treatment of -18 C for 5 hours has no observable effect on the quality of wheat, maize and soybean (Dohino et al 1999). Freezer temperatures are acceptable for the quality of some durable products, such as rice, but would normally destroy perishable commodities. Suitable products and uses Cool and cold treatments can be applied to grains and a wide variety of durable products and artifacts any item that can withstand cold temperatures without suffering quality damage. Due to cost, freezing treatments are limited mainly to high-value products, such as organic products. Cold treatments are suitable as part of an IPM system for cold storage warehouses or for structures, particularly in countries with low ambient winter temperatures. Table provides examples of products where cold treatments have been approved for quarantine purposes. Suitable climates and conditions Cold treatment aeration of stored products is suitable for temperate climates and warm climates with cool, dry night air. It can also be used in hot or humid climates, if the air is conditioned by refrigeration systems. Cold and freezer treatments are feasible in any location where refrigeration is available. Table Examples of quarantine treatment schedules utilising cold treatments Commodities and countries Carambola exported from Florida USA to Japan Carambola exported from Hawaii to mainland USA Carambola shipped from Florida to California USA Citrus exported from Australia to Japan Citrus exported from Florida USA to Japan Citrus exported from Israel to Japan Citrus exported from Mexico or Central America to USA Citrus exported from South Africa and Swaziland to Japan Citrus exported from Spain to Japan Citrus exported from Taiwan to Japan Grapes exported from Chile to Japan Kiwifruit exported from Chile to Japan Items that carry insects in soil on importation into the USA Quarantine treatment schedule 1.1 C for 15 days to control Caribbean fruit fly C for 12 days to control fruit flies 1.1 C for 15 days 1 C for days to control Mediterranean fruit fly and Queensland fruit fly (B. tryoni) 2.2 C for days to control Caribbean fruit fly (Anastraeptha suspensa) C for days 0.6 C C for days to control Mexican fruit fly (treatment not used commerically) -0.6 C for 12 days to control Mediterranean fruit fly (C.capitata) 2.0 C for 16 days to control Mediterranean fruit fly 1 C for 14 days to control Oriental fruit fly (B. dorsalis) 0 C for 12 days to control Mediterranean fruit fly 0 C for 14 days to control Mediterranean fruit fly C for 5 days Compiled from: MBTOC 1998, USDA-APHIS 1993, 1998

129 Table Products where cold treatments are approved as quarantine treatments Commodities Examples of approved quarantine applications Cold treatments for perishable commodities Apple From Mexico, Chile, South Africa, Israel, Argentina, Brazil, Italy, France, Spain, Portugal, Jordan, Lebanon, Australia, Hungary, Uruguay, Ecuador, Guyana and Zimbabwe to USA Cherry From Mexico, Chile and Argentina to USA Grape From Chile to Japan From South Africa, Brazil, Colombia, Dominican Republic, Ecuador, Peru, Uruguay, Venezuela and India to USA Citrus From Australia, Florida USA, Israel, South Africa, Spain, Swaziland and Taiwan shipped to Japan From South Africa (Western Cape) and 23 countries to USA Orange From Israel, Mexico, Spain, Morocco, Costa Rica, Colombia, Bolivia, Honduras, El Salvador, Nicaragua, Panama, Guatemala, Venezuela, Guyana, Belize, Trinidad & Tobago, Suriname, Bermuda, Italy, Greece, Turkey, Egypt, Algeria, Tunisia and Australia to USA Interstate USA Clementine From Israel, Spain, Morocco, Costa Rica, Colombia, Guatemala, Honduras, Ecuador, El Salvador, Nicaragua, Panama, Venezuela, Suriname, Trinidad & Tobago, Algeria, Tunisia, Greece, Cyprus and Italy to USA Interstate USA Tangerine From Mexico, Australia and Belize to USA Interstate USA Grapefruit From Israel, Mexico, Costa Rica, Guatemala, Honduras, El Salvador, Nicaragua, Panama, Colombia, Bolivia, Venezuela, Italy, Spain, Tunisia, Australia, Suriname, Trinidad & Tobago, Belize, Bermuda, Cyprus, Algeria and Morocco to USA Interstate USA Peach From Mexico, Israel, Morocco, South Africa, Tunisia, Zimbabwe, Uruguay and Argentina to USA Nectarine From Israel, Argentina, Uruguay, Zimbabwe and South Africa to USA Apricot From Mexico, Israel, Morocco, Zimbabwe, Haiti and Argentina to USA Plum From Mexico, Israel, Morocco, Colombia, Argentina, Uruguay, Guatemala, Algeria, Tunisia, Zimbabwe and South Africa to USA Plumcot From Chile to USA Kiwifruit From Chile to Japan From Chile, Italy, France, Greece, Zimbabwe and Australia to USA Pear From Israel, Chile, South Africa, Morocco, Italy, France, Spain, Portugal, Egypt, Tunisia, Algeria, Uruguay, Argentina, Zimbabwe and Australia to USA Persimmon From Israel, Italy and Jordan to USA Pomegranate From Israel, Colombia, Argentina, Haiti and Greece to USA Lychee From China, Israel and Taiwan to USA Loquat From Chile, Israel and Spain to USA Quince From Chile and Argentina to USA Carambola From Hawaii, Belize and Taiwan to USA Pummelo From Israel to USA Mountain papaya From Chile to USA Ya pear From China to USA Ethrog From Israel, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, Panama, Morocco, Spain, Italy, France, Greece, Portugal, Tunisia, Syria, Turkey, Albania, Algeria, Belize, Bosnia, Macedonia, Croatia, Libya, Corsica and Cyprus to USA Durian To USA Avocado (Sharwill) From Hawaii to mainland USA Freezer treatments Items carrying To USA soil with insects Compiled from: MBTOC 1998 and USDA-APHIS 1998 Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 117

130 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 118 Toxicity and health risks Cold treatments do not involve the use of toxic fumigants. Exposure to cold temperatures can present a health hazard for staff who do not have appropriate clothing and training. Cooling and refrigeration equipment must be properly maintained, and certain refrigerants (e.g., ammonia) pose a risk of toxicity, if equipment is not properly maintained. Safety precautions for users Safety training is necessary for working in cold temperatures and handling cold products. Residues in food and environment None. Ozone depletion Many refrigeration units and freezers contain ODS, so it is highly desirable to select equipment that does not, whenever possible. Global warming and energy consumption For aeration, moderate amounts of energy are consumed in the operation of fans. The operation of refrigeration units and freezers requires substantially more energy, and some refrigeration equipment contains HFCs, which are greenhouse gases (GHG). The selection of GHG-free equipment with reasonable energyefficiency ratings can help to mitigate these undesirable impacts. In some situations, it may be possible to use local renewable sources of energy. Other environmental considerations If refrigeration equipment is not properly maintained, refrigerants may leak out. In general the equipment has a very long life, and theoretically many of the component parts could be re-used. Acceptability to markets and consumers Cold treatments are highly acceptable to supermarkets, purchasing companies and consumers, because they are non-chemical treatments. Some cold treatments give products of better quality than those with MB fumigation. Registration and regulatory restrictions There is no regulatory approval required for aeration or cold treatments. However, any treatments to be used for quarantine purposes need to be approved by the importing country. (See Table for examples). Cost considerations In the case of aeration, the capital costs can be less than the cost of one year s application of MB. Bulk grain aeration needs ductwork similar to MB fumigation, as well as a control system and fans. Labour costs of aeration are probably cheaper than MB, because automatic controls are normally used. For cool and cold treatments, the capital costs are higher than MB, while labour costs are similar. The cost of cold treatments for durables may be too high in regions with high ambient temperatures, although cold treatments for perishable commodities can be economic where products have to be chilled in any case to extend shelf life. Questions to ask when selecting the system What level of pest control needs to be achieved? What temperatures can the product withstand without damage? Can the commodity be treated while in storage or in transit, or does it need a special, rapid treatment? Is sufficient cool air available during the day or night? Would aeration fit into the present commodity management system?

131 Table Suppliers of products and services for cold treatments Type of equipment or service Equipment for grain aeration, e.g. ventilation ducts, fans and aeration control systems Equipment for cold treatments, e.g. industrial refrigeration and freezer units, heat pumps Company name Agridry Rimik, Australia AllSize Perforating Ltd, Canada Avonlea, Canada Other suppliers of aeration controllers can be found on the Internet. Contact local cool storage and freezer facilities (e.g. frozen food and meat storage facilities) to ask about surplus capacity or local sources of equipment. Specialists, advisory services and consultants on cold treatments for durable commodities and structures Specialists, advisory services and consultants treatments for perishable commodities What changes can be made to the commodity management system to enable a cold treatment to be used? Is there un-used cool store or freezer capacity in local food warehouses, meatprocessing facilities, etc.? What are the costs and profitability of different types of cold treatment? What are the costs and profitability of this system compared to other options? Canadian Grain Commission, Canada CSIRO Stored Grain Research Laboratory, Australia Insects Limited, USA Dr Jonathan Donahaye and Dr Shlomo Navarro, Volcani Institute, Israel Dr Paul Fields, Cereal Research Centre, Canada Dr Judy Johnson, HCRL Fresno, USDA, USA American President Lines, USA Crop and Food Research, Postharvest Disinfestation Programme, New Zealand TransFresh, USA Dr Jack Armstrong, Tropical Fruit and Vegetable Reserach Laboratory, USDA, Hawaii Dr Walter Gould, Subtropical Horticulture Research Station, USA Dr Michael Lay-Yee, HortResearch, New Zealand Dr Robert Mangan and Dr Krista Shellie, Subtropical Agriculture Research Laboratory, USA Dr Lisa Neven, YARL, USDA, USA Note: Contact information for these suppliers and specialists is provided in Annex 6. Availability Equipment for aeration, cold and freezer treatments are very widely available. Suppliers of products and services Table provides examples of suppliers of products and services for cold treatments, as well as specialists in these techniques. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 119

132 6.3 Contact insecticides not normally registered for use on processed foods. Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 120 Advantages Long-lasting protection against pests. Require less skill than application of MB. Gas-tight enclosures not needed. Relatively quick application time. Disadvantages Cannot replace MB entirely; normally need to be combined with other practices. Can be used only for products and uses for which they are registered or officially permitted. Slow action against pests, except for dichlorvos. Poor penetration of commodities. Insect populations can develop resistance to insecticides. Many insecticides are toxic to humans, animals and the environment. Residues in food. Technical description Contact insecticide is a term that covers a wide range of chemical products toxic to pests. Contact insecticides act against insects in different ways, depending on the nature of the particular chemical. Most are directly toxic to pests, but some work by disrupting normal insect processes. As a group, they are effective in controlling a relatively wide range of pests, but they act slowly and need to be used with other treatments or practices. For stored grain, insecticides can provide a useful means of avoiding the circumstances in which fumigation becomes necessary. Where permitted, they can be applied directly to grain, storage buildings, transport vehicles, artifacts, wood products and non-edible perishable commodities. Contact insecticides are Application time for contact insecticides is relatively short. Unlike fumigants, they do not readily penetrate bagged or bulk grain, but they can provide persistent protection against infestation, lasting from less than 1 month to 24 months, depending on factors such as the active ingredient, pest species, temperature and humidity (GTZ 1996). This persistence is an advantage in products stored for long periods but a disadvantage if significant residues remain when products are sold. After continued use, insects may develop resistance to particular insecticides or groups of insecticides, so resistance management strategies are necessary. In a number of situations, resistance can be managed by using different treatments in rotation. Contact insecticides are toxic not only to target pests but also to humans, animals and the environment (see Annex 3), so they are subject to a number of regulatory controls and should be used only by trained personnel. As with other pesticides, insecticides have to be registered for specific commodities and purposes, and their use varies widely with the country, market preference and local regulations. In part because they leave residues in food, some countries have been moving away from this method of pest control. Commercial formulations contain one or more active ingredients as well as carriers and special additives. The active ingredients are the chemicals that act against pests; additives and carriers improve adhesion, act as synergists or otherwise affect performance. The main groups of active ingredients are as follows: Organophosphate (OP) compounds OPs, such as chlorpyrifos methyl, dichlorvos, fenitrothion, malathion and pirimiphos methyl, are used in many countries. They can be effective against many of the storage

133 pests, but most OPs have limited efficacy against bostrichids. The stability of their deposits on grain varies widely according to the formulation and ambient conditions, particularly temperature and moisture. For example, dichlorvos typically acts quickly and degrades within a few days; malathion takes several weeks to degrade; and pirimiphos methyl degrades over many months (MBTOC 1998). Borates Borates, such as boric acid and disodium octaborate tetrahydrate, are inorganic compounds based on boron. When ingested by pests, borates are effective against many wood-destroying organisms and cockroaches. They can be used as remedial treatments for timbers, artifacts and wood in structures (Lloyd et al 1997, Dickson 1996). They have low toxicity to humans (Olkowski et al 1991). Concern with the toxicity of OPs may lead to additional restrictions in the USA and other countries. Dichlorvos differs from other OPs in its rapid action against pests and volatility on grain. Where permitted, it can be sprayed onto bulk grain during grain turning a few days prior to export to disinfest a cargo. In some cases it can replace MB directly. Pyrethroids Pyrethroids, such as permethrin, cypermethrin, cyhalothrin and deltamethrin, are chemicals based on the active ingredient of pyrethrum. They are particularly effective against bostrichid and dermestid beetles. Some pyrethroids are very stable on grain and their insecticidal activity may persist up to two years (Snelson 1987). Their activity is much less sensitive to temperature than that of the OPs, but they are relatively expensive. Most pyrethroids have low acute toxicity to human beings. Insect growth regulators (IGRs) IGRs are not normally directly toxic to adult pests but disrupt or interfere with the life cycle or development of pests. Methoprene, for example, is an analogue of a juvenile hormone. IGRs are considered to be more pestspecific than conventional contact insecticides. One disadvantage is their long persistence on foodstuffs, which may limit their use to non-food products like stored tobacco. IGRs tend to have low toxicity to vertebrates (Menn et al 1989 in MBTOC 1994). They are relatively expensive. Combined products Combined products are also available in some cases, providing a broader spectrum insecticide. Examples of OPs mixed with pyrethroids include pirimiphos methyl with permethrin and fenitrothion with cyfluthrin. Insecticide products are available in a variety of formulations, including: Dusts ready for use, for mixture with commodities or surface treatments. Emulsifiable concentrates mixed with water, mainly for surface treatments. Wettable powders mixed with water for surface treatments. Flowable concentrates for surface treatments. Hot fogging concentrates ready for use or diluted with diesel or kerosene for space treatments. Application of insecticides varies as well. The following are the primary methods of application: Admixture with commodities. Where registered, insecticides can be applied directly to grain during handling, e.g. prior to bagging or on grain conveyors and elevators. Surface treatments. Insecticides can be sprayed onto the surfaces of bagstacks, walls and floors of empty structures, transport vehicles, artifacts and timber. In general, contact insecticides work bet- Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 121

134 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide ter on clean, smooth surfaces than they do on dirty or rough ones; they persist better on surfaces such as metal, wood and polypropylene packaging than they do on concrete, bricks, alkaline paint, whitewash and jute bags (GTZ 1996). Repeated surface spraying can lead to the development of pest resistance. Space treatments. Spaces of structures can be treated by fogging or spraying with small particles (often less than 50 microns in size). This treatment assists in the control of flying pests but usually has to be combined with other practices or treatments, because it does not penetrate between stacked bags and fails to control many hidden insects. Aerosol formulations. Aerosol formulations of insecticides, such as dichlorvos and permethrin, are used on cut flower exports as a quarantine treatment in limited cases (i.e., New Zealand and Hawaii). They do not penetrate as well as MB and require long exposures, from 3 to 16 hours (MBTOC 1998, Hara 1994). Chemical dips. Certain perishable commodities can be dipped in insecticide solutions to control pests. Insecticide dips can provide an effective treatment for some cut flowers (Hara 1994). Application techniques and safety precautions for contact insecticides are described in publications such as GTZ (1996) and the instructions or manuals of product manufacturers. Instructions should always be followed, and products should only be used where they are registered. Table Comparison of contact insecticides with fumigants Insecticides Fumigants Physical Liquids or powders Gases Time to kill pests Longer period, because insects in 2-15 days, depending on pre-adult stages are not affected temperature, pest stages and until they develop into adults sealing of enclosure Application manner Commodity normally has to be Normally treated in-situ; bulk moved to apply insecticide grains can be treated Pest protection Pest suppression mainly Disinfestation mainly Pests controlled Individual products are selectively Generally effective against many effective against different insect insect species species or groups Pest resistance With continued use most insect No incidence of significant pests develop resistance to MB tolerance is known, but particular insecticides or groups development of resistance to of insecticides phospine is a concern Duration of effect Long-lasting pest control Short-lived control Commodity range Products which will be processed, Most products and non-food products Personnel Semi-skilled operators Skilled, certified personnel 122

135 Table Examples of commercial use of contact insecticides Commodities/uses Stored grains in many countries Stored tobacco Artifacts in museums and repositories Museum items, artifacts, books and antiques in Japan Wood preservation in Germany, Australia and New Zealand Sawn timber in USA and Japan Logs imported into Japan Spot treatments of wood in structures in many countries Wooden pallets in Australia infested with wood pests Cut flowers in Hawaii and Thailand Fresh tomatoes exported from Australia to New Zealand Current uses A variety of contact insecticides are in commercial use. (See Table ) OPs, for example, are used on stored grain and storage structures. Insecticides are used in food production plants in many countries. In some cases they have been approved as quarantine treatments; Japan, for example, has approved a combination treatment where logs are immersed in water and an insecticide mixture is applied to the exposed surface (MBTOC 1998). Insecticide dips provide a common post-harvest treatment for cut flowers (Hara 1994). However, the use of insecticides is restricted to the products and countries where they are registered. Variations under development Botanical insecticides derived from plants, e.g., azadirachtin. Additional types of IGRs (MBTOC 1994). Material inputs Pesticide product. Treatments OPs, pyrethroids or IGRs Methoprene (an IGR) Pyrethroids or OPs Cyphenothrin Borates Borates Water immersion + insecticide quarantine treatment OPs, pyrethroids or borates Insecticide mixtures applied under pressure Malathion dip Dimethoate dip Compiled from: MBTOC 1998, Olkowski et al 1991 Application equipment appropriate for the product, e.g., dusters, sprayers, fogging machines. Safety equipment, such as protective overalls, face shield or respirator, goggles, gloves and boots. Personnel monitoring devices for safety. Factors required for use Appropriate temperature and moisture range for the formulation. Products that are registered for the specific commodity or use. Pests controlled Insecticides are effective against selected groups of stored product pests. Where registered, some can contribute to an IPM programme for pest suppression. Over longer periods some can achieve disinfestation when the immature pests in the product develop into adults and are killed by the insecticide. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 123

136 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 124 Organophosphate compounds can be effective against a wide range of stored product pests although higher doses are necessary for certain pest groups such as bostrichids. Dichlorvos acts rapidly. Pyrethroids are effective against bostrichid and dermestid beetles at a much lower dosage than that required for most other insect pests (MBTOC 1998, Snelson 1987). IGRs can be pest-specific, but methoprene is effective against many stored product pests including Lasioderma serricorne, Ephestia cautella, Oryzaephilus surinamensis, Plodia interpunctella, Rhyzopertha dominica and Trogoderma granarium. It is not very effective against Sitophilus spp. (Mkhize 1986, Snelson 1987). Borates are effective against many wood-destroying organisms (Carr 1959, Barnes et al 1989, Dickinson and Murphy 1989, Drysdale 1994, Nunes 1997, Manser and Lanz 1998). Higher application rates are required for controlling termites (Lloyd et al 1998). Boric acid dusts control cockroaches in 5 to10 days, as well as silverfish, carpet beetle and certain other insects (Olkowski et al 1991). Other factors affecting use Product quality Insecticide residues remaining in food products can reduce the market value in some countries. Purchasers increasingly demand commodities with negligible residues. Suitable commodities and uses Insecticides can be used on a wide range of durable products, artifacts and structures. Some formulations are only suitable for nonfood products. The approved uses of insecticides vary greatly from one country to the next, but regulatory authorities and product labels should provide the relevant information. Suitable climates and conditions Insecticides are effective in most climates, although the rate at which they degrade normally increases with temperature and moisture. They can be used in bulk bins, silos, bags, stacks or structures, provided they can be applied at an appropriate stage, such as when grain is being moved. Toxicity and health risks Pesticides, designed to kill living organisms, are by definition toxic substances. Most are acutely toxic, while some also pose chronic health risks (see pesticide data sheets in Annex 3). The mixing and application of pesticides can pose health and safety risks to applicators and staff. Empty containers and improperly stored pesticides pose health risks to local communities. Accumulated residues in food can pose risks to consumers. Safety precautions for users Handling of pesticides requires thorough safety training, safety equipment and appropriate management and emergency procedures. Product labels and safety instructions must be followed. Residues in food and environment Pesticides can leave undesirable residues in products, water and other parts of the environment, particularly when applications are repeated or where pesticide containers are dumped. Ozone depletion None of the insecticides listed in this chapter are known to be ODS. Global warming and energy consumption These insecticides are not known to be greenhouse gases. Pesticide products require energy for their manufacture and distribution.

137 Other environmental considerations Some insecticides are derived from nonrenewable materials. Empty product containers can be a source of environmental pollution and must be disposed of properly. Acceptability to markets and consumers There is increasing concern about insecticide use and residues. In general, consumers do not like chemical treatments for food products, and supermarkets increasingly favour residue-free foods. Registration and regulatory restrictions Normally, insecticide products can only be marketed, if the government authorities that control pesticide registration have approved them. In addition, food or health authorities normally limit residues in food products. Pesticide use is normally restricted to specific products and applications. Most governments also place restrictions on pesticide marketing, labels, disposal and other aspects of pesticide use. Cost considerations Insecticides are typically cheaper than MB, although some of the new insecticide products are more expensive. The labour costs associated with insecticides are often less than those associated with MB, because they require semi-skilled personnel rather than skilled, certified personnel. Questions to ask when selecting the system What level of pest control needs to be achieved? Which pests need to be controlled, and which insecticides would control them? If disinfestaton is required, will there be sufficient time to achieve it? Is there a suitable stage of product handling during which insecticides can be applied? Can the product-handling procedures be changed to accommodate pesticide applications? Which formulations are permitted for the commodity and situation? What residue limits apply to the commodity? Will customers or supermarkets be concerned about residues or use of toxic substances? What safety procedures, equipment and training would be required? What precautions can be taken against pest resistance? What are the costs and profitability of this system compared to other options? Availability Contact insecticides are available in many countries. Suppliers of products and services Examples of specialists and consultants are given in Table Since the permitted pesticide products vary greatly from one country to another, individual suppliers are not listed. Contact with local pest control product suppliers is recommended, as is verification of registration information with national or state pesticide authorities. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 125

138 Table Examples of suppliers of products and services for contact insecticides Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Type of equipment or service OPs IGRs Borates Safety equipment Specialists, advisory services and consultants Organization or company Approved formulations vary from country to country; refer to local pest control product suppliers. Refer to local pest control product suppliers. Borax Europe Ltd, UK NISUS Corp, USA Permachink Systems, USA Remmers, Germany Sashco Sealants, USA Seabright Laboratories, USA (cockroach traps) Van Waters & Rogers, USA US Borax Inc, USA (TIM-BOR wood treatment) Refer to local pest control product suppliers. Refer to local pest control product suppliers. Canadian Grain Commission, Canada Cereal Research Centre, Canada CSIRO Stored Grain Research Laboratory, Australia GTZ, Germany Insects Limited, USA Mission de Coopération Phytosanitaire, France Natural Resources Institute, UK (stored products) Technical Centre for Agricultural and Rural Cooperation, Netherlands Timber Technology Research Group, Department of Biology, Imperial College, UK (timber) Urban Pest Control Research Center, Virginia Polytechnic Institute and State University, USA Dr Jonathon Banks, Piallaigo, Australia (stored products) Dr Brad White, University of Washington, Seattle WA, USA (timber treatments) Dr LH Williams, USDA Forest Experimental Station, USA. (timber) Note: Contact information for these suppliers and specialists is provided in Annex

139 6.4 Controlled and modified atmospheres Advantages Effectively controls a wide range of pests including rodents. Most methods pose relatively few safety issues and normal work can continue near treatment areas. Nitrogen and carbon dioxide do not leave undesirable residues in food. Treatments can be carried out in-transit. Can be tolerated by all durable commodities. Disadvantages Treatments are normally slow, unless combined with pressure or heat. Most methods require good sealing. Treatments do not kill fungal pests. Technical description Because insects need oxygen to breathe and survive, the percentage of oxygen in storage containers can be reduced to levels at which insects stop feeding and reproducing. Normally air contains 21% oxygen, but if oxygen levels are held below 1% for 2 to 3 weeks, most insect species are killed. Rodents are killed when oxygen is reduced to about 5%. Controlled and modified atmospheres are normally used as part of an IPM system for managing stored product pests or for disinfestation. When used in well-sealed stores, a single treatment gives a high level of protection against pests, because it controls pests already in the commodity and the seal prevents re-invasion. It is suitable for bagged or bulk grain and other durable commodities, where it is feasible to arrange treatments of more than two weeks (MBTOC 1998). Oxygen is reduced passively in the case of modified atmospheres and hermetic storage, for example, by putting grain in sealed storage units so that insects slowly use up the available oxygen and cease activity or die. Alternatively, high levels of carbon dioxide or nitrogen gas can be pumped into storage containers or sealed sheets. The objective is either to provide a level of carbon dioxide toxic to insects (more than 60% in air) or to reduce oxygen levels to less than 1%. Some of these techniques are approved quarantine treatments. Treatment times for disinfestation can vary from one to four weeks or up to eight weeks in the case of artifacts and museum items, depending on the insect species, its life stage, temperature, commodity, and the method used. Treatment times can be reduced substantially by adding pressure or heat. There are several techniques for creating controlled or modified atmospheres described below (see Table for summary). Hermetic storage Hermetic storage involves sealing products in air-tight containers or enclosures with minimal air-space, so that insects slowly use up the oxygen and many die (Annis and Banks 1993, Navarro et al 1984, Navarro et al 1993, Varnava et al 1994). Once the unit has been properly sealed, no further treatment is necessary, but the container must be checked regularly to ensure it remains sealed and oxygen remains low. If the initial number of insects is low and the container allows some air leakage, however, pest populations may survive indefinitely at very low levels. In regions with significant temperature fluctuations, it is normally necessary to place a thick layer of absorbent waste material, such as maize cobs, on top of the grain so that moulds do not produce mycotoxins in the stored product. Hermetic storage is best done Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 127

140 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 128 underground to reduce gas losses and keep termperatures stable. Hermetic storage systems can include: Concrete platforms, bunkers and silos. Portable cocoons. Vacuum-sealed retail packs; sealed packs (up to 50kg) containing sachet of oxygen-remover e.g. activated iron powder. Nitrogen storage Products are sealed in silos, containers or inside well-sealed, gas-tight fumigation sheets (Banks and Annis 1997, Cassells et al 1994, Hill 1997). Nitrogen, an inert gas, is released into the container and pushes out the air, with the aim of reducing oxygen levels to less than 1%. The gas must be topped up from time to time to ensure oxygen levels remain at the desired level. Nitrogen can be supplied as a liquefied gas in cylinders from commercial suppliers or made on site with machines that remove oxygen from the air and deliver a gas stream containing about 0.5% oxygen. The treatment time for total disinfestation depends heavily on the temperature of the commodity but is typically one to four weeks. Nitrogen storage is most effective when grain is more than 20 C; at lower temperatures a very long treatment time is needed for complete disinfestations if tolerant pests and stages (such as Sitophilus pupae), are present (Banks 1999). Nitrogen systems are effective in reducing mould growth in higher storage moistures (16 to 18% moisture), but anaerobic fermentation can take place at moisture levels above this. A major export terminal in Australia regularly treats bins of grain (2,000- tonne capacity) with nitrogen, requiring about 1m 3 of nitrogen per tonne of grain (Batchelor 1999). Carbon dioxide storage or treatment Effective treatments involve the release of carbon dioxide gas into well-sealed enclosures. The gas displaces the air, with a typical initial target atmosphere of more than 60% carbon dioxide. In some cases, 80% carbon dioxide is required (Banks et al 1991). Depending upon the target pest, carbon dioxide concentration should not fall below 40 or 50% in the first 10 days of treatment. At 25 C the total treatment period should be at least 15 days (MBTOC 1998). Carbon dioxide works faster than nitrogen because it has a direct toxic effect on insects. The gas may have to be topped up to keep carbon dioxide levels high. The treatment time for disinfestation of grain is typically two to three weeks. An in-transit treatment is used for groundnuts shipped from Australia. Carbon dioxide and pressure The combination of carbon dioxide and pressure (e.g., about 25 bar) can reduce the disinfestation time to less than 3 hours (Caliboso et al 1994, Reichmuth and Wohlgemuth 1994, Prozell and Reichmuth 1991, Prozell et al 1997). Treatments are typically conducted in pressure-proof chambers with 20 mm steel walls. The equipment has a high capital cost but provides a very rapid quarantine treatment for high value durable products. For all of the modified atmosphere treatments discussed above, the air-tightness of stores or containers is an important factor for effective control. Some existing structures can be adapted. In the case of silo bins, the level of sealing required for carbon dioxide or nitrogen is greater than the level of sealing typically used for MB fumigations in developing countries but similar to the level of sealing required for MB for safety reasons in a number of developed countries. Where systems provide a continuous flow of gas, such as with a gas burner, the use of somewhat less gas-tight enclosures is feasible as well (Bell et al 1993, 1997a). Certain conditions, such as a large difference between the grain and ambient air temperatures, can cause moisture to migrate to the grain surface. Precautions to prevent or ameliorate

141 moisture migration are required for long-term storage. Improved application systems to reduce cost and increase convenience. A wide range of techniques has been developed for bulk or bagged commodities held in different types of structures. Carbon dioxide and nitrogen systems can include: Fixed bunkers and silos. Portable cocoons. Fumigation under sealed sheets. Retail packs. In-transit treatments for export products. Port-side treatments prior to export. Carbon dioxide, however, may be unsuitable for concrete structures such as grain silos, because the gas can cause corrosion in concrete (Taylor et al 1998). Variations under development Hermetic store with vacuum pump for rapid disinfestation (GrainPro). Material inputs For hermetic storage: gas-tight containers, e.g., semi-underground bunkers, plastic (PVC) sheets, PVC cocoons; waste material to place on top layer of grain; reflective sheet or cover for top of container to reduce moisture migration. For nitrogen treatments: gas-tight containers or fumigation sheets sealed with gas-tight glues; supply of nitrogen gas in cylinders, or equipment for extracting nitrogen from air; monitoring device. For carbon dioxide treatments: gas-tight containers or fumigation sheets sealed with gas-tight glues; source of carbon dioxide; monitoring device. For in-transit systems: as above, plus a system for topping up the carbon dioxide concentration to replace losses from leakage. For retail pack systems: barrier film plastics for making packs; adaptation of Table Comparison of hermetic storage, nitrogen and carbon dioxide treatments Hermetic Nitrogen Carbon dioxide Atmosphere Low oxygen, Less than 1% oxygen More than 60% preferably less carbon dioxide than 1% Degree of Pest management; Pest management; Pest management pest control disinfestation in disinfestation is feasible and disinfestation long-term storage Pests Storage pests Storage pests Storage and quarantine pests Equipment Very well sealed Very well sealed containers, Very well sealed containers nitrogen gas and applicator containers, carbon dioxide gas and applicator Typical 4 weeks or more 3 weeks 2 weeks treatment times Suitable Stored products Stored products, Stored and export products museum objects products, museum objects Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 129

142 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 130 packing system to allow gas flushing and good sealing when packages are filled. Factors required for use For hermetic storage: a long period for treatment, e.g., storage period of more than four weeks. For nitrogen treatments: a cheap source of nitrogen gas; several weeks for treatment if long-term storage is required subsequently. For carbon dioxide treatments: a cheap source of carbon dioxide gas, preferably captured from a local industrial process; at least two weeks for carrying out treatment if long-term storage is required. Pests controlled Oxygen levels of less than 1% for at least 2 weeks (at > 20ºC) kill most stored product insects, but the response of different species to low oxygen levels varies widely. Many are killed in a day or less at 25 C, but certain stages of some tolerant pests (such as grain weevils) may survive for 2 weeks or more. Low temperatures protect insects against the effect of low oxygen atmospheres, extending the necessary treatment period. In general, hermetic storage is suitable for pest suppression, while carbon dioxide and nitrogen can be used successfully for pest suppression or disinfestations. Specific examples of pest control include the following: High carbon dioxide atmospheres (above 60% CO 2 ) control most stored product pests in 2 to 3 weeks at 25 to 30 C. As an extreme case, Trogoderma granarium in diapause stage requires exposures longer than 17 days (at 30 C or less) (Spratt et al 1985). Carbon dioxide concentrations of 40-80% (depending on the species) provide disinfestation in warehouses and silos for a number of stored grain pests. Necessary exposure periods vary from 5 to 35 days depending on the pest species and temperature (Table 6.4.2) (Soma et al 1995, Kishino et al 1996, Kawakami 1999). Humidified nitrogen in gas-tight enclosures can control all stages of museum insect pests, if oxygen levels are less than 1% for up to 30 days (Strang 1996). Exposure to carbon dioxide and pressure of 30 kg/cm 2 kills all insects including immature stages (Caliboso et al 1994, Reichmuth and Wohlgemuth 1994). Controlled atmospheres can control some pest species in perishables, such as thrips, aphids and beetles (Anon 1993b, Kader 1985, 1994). In general, hermetic storage is suitable for pest management, while carbon dioxide and nitrogen can be used for both disinfestation and pest management. Table provides examples of carbon dioxide disinfestation schedules developed in Japan for major pests of stored grain. Additional data on exposure times for controlling many species and stages of stored product pests under specific conditions can be found in Annis (1987), Banks and Annis (1990), Bell and Armitage (1992), Bell (1996), Kishino et al (1996), Navarro (1978), Soma et al (1995) and Storey (1975). Data on exposures to control pest species of perishable products can be found in Kader (1985, 1994), Shellie (1999) and Hallman (1994). Current uses Controlled atmospheres have been used for disinfesting some dried fruits and beverage crops for many years. Carbon dioxide treatment is used on a large scale in Indonesia for long-term storage of bagged milled rice stocks (Nataredja and Hodges 1990, Suprakarn et al 1990). Hermetic storage, carbon dioxide and nitrogen treatments are used commercially for diverse products (Table 6.4.3). Hermetic systems are used for storing grains for periods of three months to several years in Cyprus (Varnava and Mouskos 1996, Batchelor 1999). Various hermetic systems

143 Table Carbon dioxide disinfestation schedules for stored grain in Japan Pests CO2 concentration Temperature Duration Granary weevil 40-80% C 35 days 25 C or above 21 days Rice weevil 40-80% C 21 days Small rice weevil C 14 days Red flour beetle More than 50% C 14 days Cigarette beetle 25 C or above 10 days Lesser grain borer 30 C or above 10 days Indian meal moth More than 50% C 7 days Mediterranean flour moth 25 C or above 5 days Almond moth have been successfully tested or used in diverse climates, including China, India, Israel, Ethiopia, Brazil and USA. Other factors affecting use Product quality If the correct concentration, temperature and duration are chosen, product quality is not diminished by the use of controlled atmospheres. On the contrary, the quality of rice stored for long periods has been found to be significantly better using carbon dioxide rather than MB, probably because repeated Source: Kawakami Table Examples of commercial use of controlled and modified atmospheres Products Stored grains in Israel and Cyprus Carry-over stocks of rice in long-term storage in Indonesia Groundnuts exported from Australia Premium grains exported from Thailand Various grains exported from Australia Artifacts and museum items in Germany and UK Beverage crops and spices in Germany Apples exported from Canada to California state, USA Treatment Hermetic storage has been used for more than a decade for bulk grains Carbon dioxide treatment is used routinely for pest management In-transit carbon dioxide treatment is applied while products are being shipped Retail packs are flushed with carbon dioxide for disinfestation and protection Nitrogen treatment (with IPM) is applied at port terminal prior to export Controlled atmospheres are increasingly used for insect control Carbon dioxide + pressure provide a rapid disinfestation treatment A controlled atmosphere treatment has been approved for quarantine purposes Compiled from: MBTOC 1998, GrainPro Inc 1999 fumigations with MB reduce grain quality and produce bromide residues. Unlike MB, controlled atmospheres do not affect the viability of dry grains such as malting barley. Suitable commodities and uses Hermetic storage and modified atmospheres are suitable for stored durable products. Controlled atmospheres are suitable for pest management and disinfestation of grains, nuts, dried fruits, beverage crops, herbs, spices, other durable commodities, artifacts and museum items where time allows. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 131

144 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Structures may be treated only if they can be well sealed and closed for several weeks. Intransit controlled atmospheres and refrigeration can be used for perishable commodities to reduce the need for quarantine treatments on arrival in the importing country (Gay 1995, EPA 1997). Suitable climates and conditions Carbon dioxide and nitrogen can be used in temperate to tropical climates. Hermetic storage can be used in a wide variety of climates provided that one of two conditions is met: Either the grain is initially sufficiently infested to assure that insects in the storage area use up all the available oxygen or the moisture content is in the range of 13 to 18%. Precautions against moisture migration are needed in climates where temperatures fluctuate. Toxicity and health risks Hermetic storage does not involve the use of toxic substances and poses no health risk (except those normally found at any grain storage area). Nitrogen is inert and not toxic in itself, while carbon dioxide is toxic at higher concentrations. Controlled atmosphere silos and containers lack sufficient oxygen for humans to breathe. There is no risk of flammability with controlled atmospheres. Safety precautions for users Hermetic storage does not require special safety precautions, but precautions and training are required for use of nitrogen and carbon dioxide gas. Residues in food and environment Nitrogen and carbon dioxide do not leave any undesirable residues in food products. For hermetic storage and situations where moisture migration may occur, suitable steps must be taken to prevent mould affecting food products. Ozone depletion Carbon dioxide and nitrogen are not ODS. Global warming and energy consumption Nitrogen is not a greenhouse gas; but carbon dioxide is. The impact of using carbon dioxide may be mitigated to some extent by using gas captured from local industries, such as smelters and distilleries. Nitrogen treatments require energy for generating the nitrogen gas and for transporting cylinders (if the gas is not extracted from air on-site). Carbon dioxide requires energy for the generation or capture of gas and transportation of cylinders. Hermetic storage does not consume energy. Other environmental considerations Controlled and modified atmospheres do not normally generate waste products. Gas cylinders are generally re-used. Acceptability to markets and consumers These treatments are regarded as non-chemical by consumers and are very acceptable to purchasing companies. Registration and regulatory restrictions Regulatory approval is not normally required for hermetic storage. It may be required for nitrogen and carbon dioxide treatments. Cost considerations For hermetic storage the initial capital costs may be higher than one year s application of MB, while the labour and operating costs are similar. In Cyprus, for example, the total capital and operating costs for a hermetic storage platform system for 4,000 tonnes of grain is about $4,500 for 1-year storage, $6,500 for 2 years storage and $8,400 for 3 years storage. This works out at about $1.12 per tonne/year for grain stored for 1 year, and $0.80 per tonne/year for 132

145 grain stored for 2 years. (Batchelor 1999). Converting existing grain bins for nitrogen treatments involves a small capital outlay. The operating cost depends primarily on the source of nitrogen gas. Licensed fumigators and expensive safety measures are not needed. A typical 3-week nitrogen treatment, using gas supplied in cylinders, in Newcastle Australia, for example, costs about $0.39 per tonne of grain for materials and labour. This compares with about $0.35 per tonne for one MB treatment (Batchelor 1999). In general, nitrogen and carbon dioxide treatments have capital costs lower than MB, while operating costs may be similar, cheaper or more expensive, depending mainly on the source of the gas. Finding a cheap source of gas can reduce the cost substantially. For storage periods of about one year or longer, carbon dioxide and nitrogen are often cheaper than MB. Questions to ask when selecting the system Which pests need to be controlled? What degree of control is necessary? Can the store be made adequately gas-tight? Can the commodity be treated while in storage or does it need a special, rapid treatment? Can logistical changes accommodate a longer treatment period? Would in-transit treatments or retail packing be feasible and useful? Is a cheap source of nitrogen or carbon dioxide available locally? Do temperature and commodity moisture affect the treatment choices? What changes need to be made to the commodity management system? What are the costs and profitability of this system compared to other options? Availability Materials and equipment are widely available. Suppliers of products and services Table provides examples of specialists and suppliers of products and services. See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 133

146 Table Examples of specialists and suppliers of products and services for controlled and modified atmospheres Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Type of equipment or service Containers and systems for hermetic storage Containers and gas-tight sheets for nitrogen and carbon dioxide treatments Equipment for generating nitrogen on-site e.g., nitrogen membrane systems Suppliers of nitrogen gas and carbon dioxide gas Controlled atmosphere treatments - a wide variety of contract services Specialists, advisory services and consultants Organization or company CSIRO, Australia GrainPro Inc, USA Haogenplast, Israel GrainPro Inc, USA Power Plastics, UK Rentokil, Germany, UK Gas Process Control, Australia Oxair Australia Pty, Australia There are many other suppliers, typically gas companies BOC Gases, most countries Consolidated Industrial Gases Inc, Philippines Industrial Oxygen Inc, Malaysia IMS Gas and Equipment Pte Ltd, Singapore Island Air Products Corp, Philippines Malaysia Oxygen Berhad, Malaysia Praxair Canada Inc, Canada PT Aneka Gases, Indonesia Thai Industrial Gases Ltd, Thailand Also contact local gas suppliers American President Lines Ltd, USA Insects Limited, USA Fumigation Services and Supply, USA GrainPro Inc, USA Permea Inc, USA SiberHegner Lenersan Poortman BV, Netherlands Rentokil, Germany and UK Thermo Lignum, Germany and UK TransFresh Corp., USA Canadian Grain Commission, Canada Cereal Research Centre, Canada CSIRO Stored Grain Research Laboratory, Australia Cyprus Grain Commission, Cyprus Federal Biological Research Centre for Agriculture and Forestry, Germany GrainPro Inc, USA GTZ, Germany Home Grown Cereals Authority, UK HortResearch, New Zealand Dr Jonathon Banks, Pialligo, Australia Dr John Conway, Natural Resources Institute, Chatham Maritime, UK Dr Jonathan Donahaye, Volcani Institute, Israel Dr Shlomo Navarro, Volcani Institute, Israel Dr Adel Kader, University of California, USA Dr Fusao Kawakami, MAFF Yokohama Plant Protection Station, Japan Dr Krista Shellie, USDA-ARS, USA Dr Thomas Phillips, Oklahoma University, USA 134 Note: Contact information for these suppliers and specialists is provided in Annex 6.

147 6.5 Heat treatments Advantages Very rapid treatment, often faster than MB fumigation. No undesirable residues in food products. Effective for disinfestation, including control of khapra beetle. Requires less sealing than MB for durable commodities. Safe for users and local communities. Does not require access restrictions near site. Disadvantages Not suitable for commodities that are damaged by heat. Not available for large grain terminals that handle more than 500 tonnes of grain per hour. Consumes substantial energy and may cost more than MB. Technical description Heat can be used to manage or kill a wide range of pests by inducing dehydration and/or coagulating proteins and destroying enzymes in organisms. Stored product pest insects, for example, can be eradicated by exposing them to temperatures of about 50 C. In general, commodities are heated to temperatures ranging from 43 to 100 C, with treatment times varying from one minute to several days depending on the commodity, pest and situation (see Tables 6.5.2). During treatments, the temperature needs to be monitored and achieved within the commodity itself, not simply in the air spaces. Both the temperature and time need to be controlled to kill the target pests yet avoid damage to products from excessive heat, loss of moisture or other changes due to heat. The speed of treatment is generally determined by the rate at which heat penetrates thick objects or commodity bulks, not by the intrinsic speed at which heat kills insects. The heat for treatments is normally generated using conventional means such as oil, electricity or gas, although in some situations it is feasible to use waste heat from other processes. Numerous techniques are available for delivering heat to durable commodities, including hot air, fluid beds and kiln drying. Steam treatments are specialised and suitable only for durable items that can sustain high humidity, such as dunnage, logs and some types of wood. In the case of perishable commodities, hot water dips, vapour heat and hot forced air techniques are in use. The many diverse techniques can be divided into the following broad groups: Heated air Air heated to a temperature of approximately 90 C is used to heat grain briefly to above 65 C. In the case of cereal grain processing plants, the typical target temperature is 50 to 55 C for 20 to 30 hours for controlling insects (Dowdy 1997). Heat applied in the process of kiln drying disinfests sawn timber and actually adds value to it. Convection heaters or existing air ducts applying temperatures above 50 C for 20 to 30 hours are used in some structures for controlling most pests except cockroaches (Heaps 1998, MBTOC 1998). Target temperatures must be achieved in places where insects may be hidden, such as ducts, voids and pipe work. Structural heat treatments are normally combined with IPM and applied several times a year. Fluid bed system High-speed fluid bed systems for treating bulk grain have been built and developed to commercial prototype stage and successfully handle up to 150 tonnes of grain per hour (Sutherland et al 1987, Evans et al 1983, Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 135

148 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 136 Thorpe et al 1984, Fleurat-Lessard 1985). Typical temperatures are 65 C within the commodity for about one minute. Installation of large-scale treatment facilities, however, is likely to be capital intensive. There are currently no heat installations of the size required to meet the typical handling speeds of large modern grain terminals, which often handle 500 tonnes/hour or more on one belt. Heat treatments with controlled humidity Artifacts and durable commodities normally lose moisture during heating, but monitoring and maintaining the moisture content of items at the same level throughout the heating and cooling process can prevent this. Artifacts and durable commodities can be treated in chambers or other containers, or the treatment may be applied as a space or structural treatment. This process is more expensive than heat alone but is very suitable for historical objects and other delicate artifacts that would normally be damaged by heat. For certain perishable commodities, such as grapefruit, papaya and mango, high temperature forced air (HTFA) treatments have been approved for quarantine. After loading commodities into a chamber, humidified air (typically 40 to 80% relative humidity) at 40 to 50 C is forced over fruit surfaces to raise the internal temperature. The temperature and relative humidity are controlled precisely to prevent condensation inside the treatment area and on commodities, protecting fruit from desiccation and scalding (Gaffney and Armstrong 1990, Sharp et al 1991). Certain perishable commodities are given vapour heat treatments that are broadly similar to HTFA, except that the relative humidity is kept above 80%. Information on HTFA and vapour heat treatments can be found in the Textbook of Vapour Heat Disinfestation of Japan (Anon. 1996), UDSA-APHIS (1998), Armstrong (1994), Hallman and Armstrong (1994), Sharp (1994) and Williamson and Winkelman (1994). Hot water immersion Water is inherently more effective than humid air as a heat transfer medium, and provides a uniform temperature profile if properly circulated through the load of commodities (Couey 1989). Hot water dips can be used to control fungi as well as insects and snails in wood and timber (MBTOC 1998). Depending on the pest and commodity, quarantine treatments for specific perishables may be accomplished with submersion in hot baths, often at temperatures between 43 and 47 C for periods from 35 to 90 minutes (MBTOC 1998, Hara et al 1994). Such treatment provides the additional benefit of control of post-harvest microbial diseases, such as anthracnose and stem end rot (Couey 1989, McGuire 1991). In-transit steaming In the USA, a method of in-transit steam heating has been developed for bulk timber and wood chips, allowing large cargoes (up to 35,000 m 3 ) to be treated hold by hold. Low-pressure steam and/or hot water at 65 to 90 C is provided by a boiler, heating the centre of the timber to at least 56 C for 30 minutes or more (Seidner 1997). Combination treatments Heat can be successfully combined with other treatments, such as controlled atmospheres and phosphine. Heat often acts as a synergist, increasing the diffusion and distribution of gases and their powers of penetration; it reduces the physical sorption of gases and increases the toxicity or level of stress to target pests (Mueller 1998). To avoid damage by heat, some durable products need to be rapidly cooled to room temperature after treatment. Delicate artifacts and antiques can withstand heat if their internal humidity is monitored and maintained at the same level throughout the

149 treatment. Some structures cannot tolerate the stresses caused by the rapid change in temperature and the differential expansion of structural components such as concrete and steel. Sensitive electrical equipment and other heat-sensitive items must be temporarily removed from structures or modified to avoid damage. Some types of grease are liquefied by heat and have to be re-applied after a treatment. Because they are susceptible to heat damage, perishable commodities require heat treatments specially tailored for each variety. Perishables that can tolerate certain heat treatments for quarantine include tomato, pepper, aubergine (eggplant), melon, cucumber, papaya, some citrus fruits, litchi, mango and cut flowers (Paull and Armstrong 1994). Computer-controlled heating techniques allow greater control and shorter treatment periods. Treatment times can also be reduced with engineering improvements that move hot air faster and more uniformly through the commodity (Paull and Armstrong 1994). The gradual heating of perishables is generally preferable to rapid heating, and a pretreatment may increase the commodity s tolerance. Heat is unsuitable for highly perishable products, such as asparagus, nectarines, avocados or leafy vegetables (MBTOC 1994, Couey 1989). Current uses Heat treatments were once widely used in warm climates for disinfestation of commodities, such as grain in Australia and cotton and cotton seed in Egypt, with large tonnages being treated (Banks 1999). In some countries heat has been routinely used to control wood-boring pests in wooden buildings for many years. Heat is also used commercially for some wood products (Table 6.5.1). Heat treatments are increasingly being adopted as part of IPM systems for food processing facilities and mills in Canada. More than 75 commercial heat facilities have been built for quarantine treatments for perishable commodities in Mexico and other countries of Latin America (EPA 1996). Variations under development Other sources of heat, such as microwaves, radio frequency heating, dielectric heating and infrared. Pre-treatments and lower temperature treatments to reduce commodity stress, allowing a wider range of commodities to be treated with heat. Improvements in the energy-efficiency of treatments. Table Examples of commercial use of heat treatments Products Wood products Wood products Food processing facilities and mills in Canada and the Netherlands Artifacts and museum items in Germany, Austria and UK Mangoes exported from the Caribbean Basin, Latin America, Australia Papaya exported from Hawaii to mainland USA, and from the Cook Islands to New Zealand Treatment Kiln drying Steam heat Hot air treatments + IPM Heat with controlled humidity Hot water immersion quarantine treatment for fruit fly Treatment with vapour heat or forced hot air quarantine treatment for fruit fly Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures Compiled from: MBTOC 1998, Batchelor 1999, Paull and Armstrong

150 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Material inputs Equipment for generating heat. Fuel. Containment or insulated sheets to place around the commodity. Temperature gauges and monitoring probes to insert in different parts of the commodity load or structure. Where humidity is important, probes and equipment for monitoring and controlling humidity. Factors required for use Products, structures and equipment that can withstand heat without being damaged by it. Know-how and training. Pests controlled All stages of stored product pest insects can be eradicated in less than one minute if they are exposed to a temperature of 65 C. Temperatures above 47 C for longer exposures are also lethal for many stored product pests (Barks & Fields 1998). Tables show the temperatures and exposure times necessary to kill pests in certain commodities. Further examples can be found in Forbes and Ebling, Banks & Fields (1998). Lethal temperatures for insects and fungal pests of perishable commodities can be found in Jang (1986), Yokoyama et al (1987, 1991) and Moss and Jang (1991). Insect mortality due to heat varies according to factors such as the species, insect stage, insect age, availability of oxygen, ph, previous temperatures, and general energy status of the insect (Moss and Jang 1991). Heat treatments can be used for pest suppression and disinfestation purposes. There are a number of heat treatments approved by quarantine authorities for particular products, and examples of these are listed in Table and Table Heat is effective in replacing MB for some quarantine disinfestations targeted at Trogoderma granarium, an important quarantine pest of grain (MBTOC 1998). Heat is one of the few treatments that is effective at disinfesting bulk grain from live snails (Cassells et al 1994). Other factors affecting use Product quality Depending on the temperature, the quality of some grains may be affected by heat, thus limiting the application to grains that will be processed. Under good process control there is no damage to the end-use qualities of cereals, such as bread-making wheat or rice, and malting quality of barley (Fleurat-Lessard 1985, Sutherland et al 1987). However, the Table Temperatures for killing pests of stored products and structures Pests and commodities Commodity temperature Further information and exposure time Cigarette beetle (Lasioderma 50 C for 24 hours kills all Meyer 1980, serricorne, all stages) stages Banks & Fields 1998 All tobacco pests Vacuum steam conditioning at Ryan C for 3 minutes Wide range of fungi in timber Steam treatment held at 66 C Chidester 1991, for 1.25 Miric and Willeitner 1990, Newbill and 1991 Dry wood termites Heating to above 44 C Lewis and Haverty

151 Table Examples of heat treatments approved for quarantine purposes for durable commodities and artifacts, USA Treatments and commodities Temperature and duration Heat treatments Any durable commodity that can tolerate 65.5 C for 7 minutes heat to control Khapra beetle Feeds & milled products for processing 65.5 C for 7 minutes Bagasse/sugarcane 70 C for 2 hours Bags for seeds 100 C for 1 hour Lumber (3" thick) with wood borers 54.4 C for 14 hours or 60 C for 7 hours Corn (maize) ears not for propagation 75.5 C for 2 hours Rice straw novelties and articles 82.2 C for 2 hours Niger seeds with soil or Khapra beetle 100 C for 15 minutes Steam treatments Niger seeds with soil or Khapra beetle 100 C for 15 minutes Seeds not for propagation 100 C Steam treatments with pressure Rice straw and hulls, straw mats 30 minutes Rice straw novelties 30 minutes Novelties and articles from broomcorn 30 minutes Vacuum steam flow process Leaf tobacco for export 76.7 C for 15 minutes Blended strip tobacco for export 71.1 C for 3 minutes Hot water dips Bulbs with Ditylenchus nematodes 24 C for 2 hours and 43.3 C for 4 hours Lily bulbs with Aphelenchoides nematodes 38.8 C Senecio with Aphelenchoides nematodes 43.3 C for 1 hour Narcissus bulbs with bulb scale mite 43.3 C for 1 hour Certain tubers with Meloidogyne spp C for 30 minutes Horseradish root with golden nematode 47.8 C for 30 minutes Banana roots 43.4 C for 30 minutes and 48.9 C for 60 minutes Sugarcane 43.3 C for 4 hours Compiled from: USDA-APHIS 1993, 1998 Table Examples of heat treatments approved for quarantine purposes for perishable commodities, USA Perishable commodities (1) Grapefruit infested with Caribbean fruit fly Mango infested with Caribbean fruit fly Papaya, pineapple, tomato, zucchini, squash, aubergine (eggplant) and bell peppers infested with Mediterranean, Oriental or melon fruit flies Temperature and duration Vapour heat at C for 5 hours Hot water at C for 75 minutes to 2 hours, depending on variety or cultivar Vapour heat at 44.4 C for 8.75 hours Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures (1) The approved treatments relate to specific varieties or cultivars in some cases Compiled from: Paull and Armstrong

152 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 140 margin of error is small and slight excesses in treatment can adversely affect the product. High temperatures lead to detrimental colour changes or rancidity in many dried fruit and nuts. If humidity is carefully controlled throughout the treatment, heat damage from moisture loss can be avoided, even in many delicate museum objects. Heat damage and protection measures for perishable commodities are outlined in Paull and Armstrong (1994), Sharp and Hallman (1994) and Lay-Yee (1994). Heat treatments can also have beneficial effects on quality, such as reducing susceptibility to chilling injury in persimmons or increasing firmness in apples and pears (Lay-Yee 1994, Neven and Drake 1998). Suitable products and uses Heat treatments at moderate temperatures are suitable for durable products, artifacts and structures that can withstand heat without damage to their market quality. The range of suitable products can be extended substantially if heat is combined with controlled humidity, because this prevents or reduces heat damage in many situations. Heat is not suitable for highly perishable products, such as asparagus, nectarines, avocados or leafy vegetables (Couey 1989) or for seeds that will be germinated (GTZ 1996). Suitable climates and conditions Heat treatments are not limited by climate and can be conducted in a wide range of regions from temperate to tropical. Toxicity and health risks Heat treatments do not involve the use of toxic substances. Heat itself, however, can present an occupational hazard, so proper safety management is required. Safety precautions for users It is necessary to have safety training for workers. Residues in food and environment Heat treatments do not leave undesirable residues in treated products. Ozone depletion Heat treatments do not use ODS. Global warming and energy consumption Heat treatments use energy for heat generation. The problem of carbon dioxide emissions from fossil fuels can be addressed by using renewable sources of energy or local sources of waste heat, where possible. A Danish project has recently improved the energy efficiency of heat treatments for wood-boring beetles, reducing energy consumption by up to 50% (Host Rasmussen 1998). Computer-control of heat treatments often allows improved energy efficiency. Other environmental considerations Surplus heat is the main waste product. Where possible, it is desirable to capture this for other constructive purposes. Acceptability to markets and consumers Properly conducted heat treatments are very acceptable to supermarkets and purchasing companies. They are highly acceptable to consumers, because they are traditional, nonchemical treatments. Registration and regulatory restrictions Registration is not normally required for heat treatments for general pest control. Prior approval is required for heat treatments to be used as quarantine treatments. Examples of approved quarantine treatments for durables are given in Table 6.5.3, while examples for perishable commodities are given in Table Normal safety restrictions apply to the use of heating appliances in workplaces. Cost considerations Heat treatments normally require a high capital investment and, in some cases,

153 involve relatively high fuel costs. Over several years, however, costs can be similar to MB in some applications. Kiln drying of softwood (e.g., Douglas fir) in the USA costs about US$ 85 to 155 per 1,000 bd. foot, while steam treatments cost US$ 35 to 60 per 1,000 bd. ft. For hardwoods (e.g., oak, cherry), kiln drying costs about US$ 100 to 200, while steam treatments cost about US$ 41 to 77 per 1,000 bd.ft. In contrast, MB fumigation costs only US$ 1 to 3 per 1,000 bd. ft. However, the heat treatments add 30 to 50% extra value to timber, so the net cost of heat treatments can be zero (US EPA 1996). For perishable products, heat treatments generally cost more than MB fumigation (Paull and Armstrong 1994). The capital cost of a hot water immersion system varies from less than US$ 8,000 to more than $ 200,000. For forced air and vapour heat systems, the capital costs vary from US$ 20,000 to about 200,000, while the capital and operating costs are estimated to be about US$ per tonne of commodity compared to about US$ 4.37 per tonne for MB (US EPA 1996). The cost of heat treatment equipment has been reduced in recent years, however (Williamson 1999). Structural heat treatments (e.g., for food facilities) cost approximately 75 to 200% of the cost of MB fumigation (Mueller 1998), depending on the size of the treatment area, the source of heat and the temperature/time equation. If a company already owns heaters, heat treatments are less expensive than MB (Heaps 1998). Otherwise a significant capital investment is required: One 250,000 BTU platform steam convection heater, for example, costs about US$ 2,300 in the USA (Heaps 1998). The operating cost of heat treatments at a US food processing plant is US$ 747 to 830 per 1 million cubic feet compared to US$ 2,000 to 4,500 for MB (US EPA 1995). Questions to ask when selecting the system What level of pest control needs to be achieved? What temperatures are required to control the target pests? What time is available to conduct the treatment? What temperature/exposure can be tolerated by the commodity or structure and equipment? Is there an available source of waste heat or steam, for example, from local food-processing operations? What changes could be made to the commodity management system to accommodate heat treatments? What are the costs and profitability of this system compared to other options? Availability General heating equipment, such as steam boilers and convection heaters, are widely available. Special equipment, such as heat units for perishable treatments, is available in some countries. Suppliers and specialists Examples of specialists and suppliers of products and services are listed in Table See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 141

154 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 142 Table Examples of specialists and suppliers of products and services for heat treatments Type of equipment or service Equipment for various types of heat treatments Consultants, specialists and advisory services for durable commodities, timber, structures Consultants, specialists and advisory services for perishable commodities Organization or company Aggreko Inc, USA Aquanomics International, New Zealand Boverhuis Boilers BV, Netherlands Department of Agricultural Engineering, University of Hawaii, USA FibreForm Wood Products Inc, USA HKB, Netherlands Ole Myhrene Krike, Norway Thermeta, Netherlands Thermo Lignum, Austria, Germany and UK Topp Construction Services Inc, USA (Safe-Heat) Tur-Net, Netherlands Quarantine Technologies, New Zealand Contact neighbouring factories and food processing facilities to ask if they generate surplus heat or steam For other suppliers of steam boilers refer to Table Cereal Research Centre, Canada Canadian Pest Control Association, Canada Copesan Services Inc, USA CSIRO Stored Grain Research Laboratory, Australia FibreForm Wood Products Inc, USA Fumigation Services and Supply, USA HortResearch, New Zealand Insects Limited, USA Quaker Oats Canada Ltd, Canada Thermo Lignum, Germany and UK Dr Bill Brodie, USDA-ARS, Department of Plant Pathology, Cornell University, Ithaca NY, USA Dr Alan Dowdy, Grain Marketing and Production Research Center, USDA-ARS, Kansas, USA Aquanomics International, New Zealand Ole Myhrene Krike, Norway (propagation plants) Thermo Lignum, Germany and UK Dr Jack Armstrong, Tropical Fruit and Vegetable Research Laboratory, USDA-ARS, USA Dr Eric Jang, Tropical Fruit and Vegetable Research Laboratory, USDA-ARS, USA Dr Arnold Hara, University of Hawaii, USA (cut flowers) Dr K Jacobi, Department of Primary Industry, Indooroopily, Australia Dr Michael Lay-Yee and colleagues, HortResearch, New Zealand Dr Robert Mangan, Subtropical Agriculture Research Laboratory, USDA-ARS, USA Dr Krista Shellie, Subtropical Agriculture Research Laboratory, USDA-ARS, Weslaco TX, USA Dr Harold Moffitt, Yakima Agricultural Research Laboratory, USDA-ARS, USA Dr Jennifer Sharp, Subtropical Horticulture Research Station, USDA-ARS, USA Dr Guy Hallman, Dr WP Gould, Subtropical Horticulture Research Station, USDA-ARS, Miami FL, USA Dr Michael Williamson, Quarantine Technologies, New Zealand Note: Contact information for these suppliers and specialists is provided in Annex 6.

155 6.6 Inert dusts Advantages Little or no capital equipment required. Relatively non-toxic. Generally simple to apply. Provide continued protection against insects. Repeated treatments are not necessary. Do not affect the baking characteristics of grains. Disadvantages Effective for a much smaller range of commodities and uses compared to other techniques. Not a rapid treatment. Adversely affects handling qualities of grain, e.g., decreased flowability, reduced bulk density. Dusts have to be separated from grain before human consumption. Visible residues in grain affect grading and market quality. Can cause excessive wear (abrasion) in grain-handling machinery. Do not control Trogoderma. Technical description Historically, inert dusts such as clays and ashes have been applied to grain to protect against insect attack (Ebeling 1971, Golob and Webley 1980, Quarles 1992a,b). More recent versions of dusts are generally more effective and require much lower application rates. Inert dusts can be divided into three main groups: a) Traditional materials Traditional materials include clays, sands, ashes, earths, phosphate and lime. Some are used as a protective layer on top of stored seed, while others are mixed with grain. To be effective, ashes and dusts generally had to be mixed with grain at extremely high rates, such as 40% or more (GTZ 1996). b)diatomaceous earth (DE) DE dusts are composed mainly of silicon dioxide with small amounts of other minerals. They are produced from the fossilised remains of diatoms, microscopic single-celled aquatic plants that have fine shells made of amorphous hydrated silica. They have abrasive and sorptive properties and are effective against a wide range of pests when mixed with grain at rates of 1 kg per tonne (MBTOC 1994). DE adheres to insect bodies, damaging the protective waxy layer of the insect cuticle or outer coat by sorption and, to a lesser degree, by abrasion. Water is lost from the insect, resulting in death. DE is also known to repel insects (Korunic 1999). c) Silica aerogels Silica aerogels are very light, non-hygroscopic powders or gels that are formed by a reaction of sodium silicate and sulfuric acid. They are chemically inert, non-abrasive and effective at slightly lower doses than DE formulations. Modern formulations of inert dusts are typically composed of DE, sometimes combined with silica aerogels. Formulations differ in their characteristics and efficacy against insects. Additives can give improved properties: ammonium fluosilicate, for example, improves adhesion to treated surfaces and insects. Certain sources of DE have naturally higher levels of insecticidal activity, while some formulations can be activated or enhanced, for example by heat treatment. Activated formulations are generally more effective than untreated DE (Golob 1997, McLaughlin 1994). Modern DE formulations used as part of an IPM system can provide effective pest control for several years in dry grain and structures. The application time for DE is short, normally Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 143

156 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 144 less than one day, and DE can control adult insects in about seven days in favourable conditions (MBTOC 1994). DE dusts remain effective for years if they are kept in sealed, dry conditions, but they become ineffective in moist or humid conditions. Successful use of DE as part of an IPM system requires knowlege of factors such as grain moisture content, grain temperature, amount of dockage (chaff, weed seeds) and broken kernels, grain type and quality, and insect species and numbers (Korunic 1999). DE is not suitable for heavily infested commodities. It provides a protective, prophylactic treatment to prevent pest build-up, so it is best used as part of an IPM system or as follow-up to another treatment such as aeration (Section 6.2) or phosphine flow fumigation (Section 6.7). Inert dusts are suitable for a relatively small range of products and uses. There are four main application areas: Admixture with stored grains In several countries, specific formulations of DE have been approved for admixture with stored grains, such as wheat, corn, barley, buckwheat, oats, pea, sorghum, seed, rye, soybeans, peanuts, cocoa beans and feed grains. In this technique, DE dust is mixed with grain when it is bagged or loaded into silos, bulk bins or bunkers. Enhanced DE is applied at the rate of about 100 g per tonne of grain and must be distributed evenly in the bulk. The moisture content of grain is critical: Less than 12% prior to storage is recommended (Banks pers. comm.). One application of DE can provide protection from infestation for several years, because the dust continues to exert its effects on insects. When the grain is milled, the dust is removed along with the grain husks. However, remaining particles in grain can reduce its market value. Inert dusts can have adverse effects on the handling qualities of grain, decreasing its flowability and its bulk density and causing excessive wear to grain handling machinery. While some technical problems have been overcome by new DE formulations (Korunic et al 1996), these problems tend to prevent the use of inert dusts in large-scale grain facilities. Admixtures are considered more appropriate for stored seed (for planting), smaller-scale farm storage of animal feed and organic grains (MBTOC 1994). Grain surface treatments DE can be applied to the surface layer of bulk grain to kill insects in the top layer where they tend to congregate. This treatment is best applied as a protective measure for grain that is already free from insects, after cooling or flow-through phosphine fumigation, for example (Bridgeman 1998). When combined with aeration in a silo, at least 300 mm of DE is applied on top of the bulk. Moisture content needs to be less than 12% when the grain is put into storage, and grain temperatures need to be kept below 20 C. In this situation, DE controls immigrant insects as well as those herded to the top of the silo by the cooling front (Bridgeman 1998). Structural treatments In the USA, certain formulations of DE have been approved for insect control in structures, such as food handling establishments, warehouses, restaurants, office buildings, homes, motels, hotels and schools. These formulations are used on wall and floor surfaces, in cracks, crevices, hiding and running areas, and under and behind appliances. DE is used commercially with IPM as a treatment for grain storage facilities in dry regions of Australia. Normal formulations of DE can pose a dust hazard to workers applying it to walls, but this problem can be overcome by using DE slurries. Although DE is normally deactivated by moisture, slurries are special formulations that can be mixed with water and become reactivated on drying. In this treatment, empty grain stores are cleared of debris and thoroughly washed and cleaned. A slurry of 0.1 kg DE per litre of water is

157 sprayed onto the walls of the storage facility with a high pressure pump, giving an application rate of about 6 g a.i. per m 2. It takes about 20 minutes to apply the slurry to a structure that holds 5,000 tonnes of grain (Bridgeman 1998). One treatment lasts several years and is very effective in controlling pests in drier regions with relative humidity below 70% (Batchelor 1999). Spot treatments in structures DE can provide long-lasting insect control in cracks and crevices of structures. For example, dusts can be applied inside electrical panels, control panels and dead spaces behind walls before they are closed up, providing lasting control in locations that are normally inaccessible (MBIGWG 1998). Spot treatments have been used in this way by a Canadian flour mill. Current uses Inert dusts such as ash and lime have had a long history of use for grain protection. Use of modern formulations has increased significantly in the last decade (Bridgeman 1998). DE is in widespread use for controlling insects in storage facilities in Australia and is used commercially for structures in Brazil, Canada, Products Stored grains in Australia Europe and the USA (Batchelor 1999). Table provides examples of commercial uses of inert dusts. A combination of DE with heat has been trialled successfully in a Canadian flour mill (Fields et al 1998). Variations under development New formulations to minimise abrasive properties and protect grain-handling machinery, such as conveyors, and to enhance desiccant properties of DE by promoting its ability to selectively absorb the waxes of insect cuticles. New methods of application (Fields et al 1997, Korunic et al 1996). Trials in damp climates such as the UK (Cook, Armitage and Collins 1999). Enhanced DE combined with heat or in various combinations with heat and phosphine to achieve higher pest mortality (Fields et al 1997). Material inputs DE product. Application equipment. Table Examples of commercial use of inert dusts Stored grains in eastern Australia Stored animal feed and seeds in Australia Wheat and empty wheat bins in parts of Canada Organic grains Storage facilities (structures) for grains, pulses and oilseeds in Australia Spot treatments for inaccessible spaces in flour mill in Canada Treatment Aeration + DE on surface layer of grain Phosphine flow fumigation + DE cap on surface layer of grain DE mixed with commodity DE mixed with commodity or applied to walls of bins Inert dusts of various types IPM + DE slurry applied to walls IPM + DE Compiled from: MBTOC 1998, Batchelor 1999, Bridgeman 1998, MBIGWG 1998, Nickson et al 1994 Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 145

158 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 146 Examples of equipment for slurry applications in structures: High pressure slurry pump and hose available off the shelf with minor modifications. Small motor (e.g., 3.5 horse power). Water tank for mixing slurry (e.g., 180- to 220-litre tank for a 5,000-tonne grain store). Safety dust mask for mixing. Factors required for use For grain admixtures: Dry grain (moisture content below about 12%) and low humidity (normally below about 70% relative humidity). Grain-handling machinery that can withstand abrasion and different flow properties in grain. Purchasers who will accept dust particles in grain. For slurry applications in facilities: Low humidity (normally below about 70% relative humidity). Low moisture content in grain or other stored commodities. Pests controlled Inert dusts, particularly when used as part of an IPM programme, can effectively manage insects and mites. DE can act quite rapidly under favourable dry conditions, achieving complete mortality of adult insects within seven days (MBTOC 1994). DE does not effectively control some pests, notably Trogoderma. Insect species vary in their susceptibility to DE as follows (most susceptible to least susceptible): Rusty grain beetle, Cryptolestes ferrugineus (Stephens). Saw toothed grain beetle, Oryzaephilus surinamensis (L.) Granary weevil, Sitophilus granarius (L.) Rice weevil, Sitophilus oryzae (L.) Lesser grain borer, Rhyzopertha dominica F. Red flour beetle, Tribolium castaneum (Herbst). Larger grain borer, Prostephanus truncatus (Horn). Further information on pest species affected by inert dusts can be found in Korunic (1999) and Cook, Armitage and Collins (1999). Table gives examples of stored grain insects and other pests that are controlled by certain DE formulations in the USA. There is also a significant variation in the efficacy of DE in different types of commodities against the same insect species. The commodities, in order of highest to lowest doses for LD 50 (dose required for killing 50% of insects) are (Korunic et al 1997): Rice. Corn. Oats. Barley. Wheat. Other factors affecting use Product quality Admixing inert dusts with grain alters the angle at which individual grains sit, changing the way grain flows and making it more difficult to handle. Admixing can also leave visible dust particles in grain, reducing its market grade and value. Structural treatments do not normally suffer from these problems. DE is odourless and does not stain grain, nor does it affect the germination and baking properties of grains. Suitable products and uses While DE is technically effective for most stored products, its use is limited by humidity, dust residue and the handling problems

159 Table Pests that can be controlled by certain DE formulations examples from USA Formulations for stored grain insects Exposed stages of pests Angoumois grain moths Cigarette beetle Flat grain beetle Granary weevil Larger grain borer Lesser grain beetle Lesser grain borer Mediterranean flour moths Merchant grain beetle Red flour beetle Rice weevil Rusty grain beetle Sawtoothed grain beetle Newly-hatched larvae Indian meal moth Red flour beetle Sawtoothed grain beetle described above. It is suitable for admixture with stored seeds that will be used for planting and for smaller scale storage of animal feed. Some formulations of DE are permitted for certified organic grains. Surface treatments and structures also offer suitable uses. Inert dusts are not used for perishable commodities. Suitable climates and conditions DE treatments are suitable for many geographical regions, provided the relative humidity in the facility is normally less than about 70%. Toxicity and health risks DE has low or no toxicity to mammals and is widely used as a permitted food additive. As with any dust, dust from DE is a potential health hazard to lungs and eyes. Certain geological sources of DE contain crystabolite, which is also a hazard to lungs in dusty conditions. Formulations for other purposes Indoor and outdoor crawling insects Ants Bedbugs Boxelder bugs Carpet beetles Centipedes Cockroaches Earwigs Fleas Millipedes Scorpions Silverfish Slugs Ticks Safety precautions for users Precautions and safety equipment are necessary against dust exposure. For structures it is often feasible to apply DE as a slurry rather than a powder to minimise the dust. Residues in food and environment When DE is admixed with grain, some dust may remain in the commodity. This does not pose a health risk to consumers and animals. DEs are permitted food additives. Ozone depletion DE is not an ODS. Compiled from: EPA, ARBICO Global warming and energy consumption DE is not a greenhouse gas. Like MB, it requires some energy for extraction, formulation and transportation. Application normally uses little energy. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 147

160 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Other environmental considerations DE is extracted from geological deposits in the ground, so there is a risk of destroying natural habitats, as with MB extraction from lakes like the Dead Sea. Acceptability to markets and consumers Mixing DE with grain is not acceptable to many grain handlers and markets, although certain milling companies favour its use (MBIGWG 1998). Structural and surface treatments are often preferable. Consumers find DE treatment acceptable in that it is a nonchemical treatment. Registration and regulatory restrictions DE often requires registration. Certain DE formulations are registered as insecticides in Australia, Brazil, Canada, China, Croatia, Germany and USA (Batchelor 1999). It is desirable to limit the amount of crystabolite allowed in products, as is done in Australia. Cost considerations For admixtures, little capital equipment is required. The material costs for one treatment are normally higher than the cost of MB, costing approximately US$ 8.80 per tonne of grain in some countries (GTZ 1998). For structures such as grain stores, the capital cost of a high pressure pump for slurry applications is about US$ 4,200 in Australia, but the pay-back period is rapid. Over 2 years, the total average annual cost (capital and operating) is US$ 3,200 for DE slurry treatment compared to US$ 5,150 for MB fumigation (Batchelor 1999). Questions to ask when selecting the system What level of infestation exists? What level of pest control needs to be achieved? Will DE control the target pest species sufficiently? What is the normal humidity range of the air and commodities in the facility? Is there an opportunity to mix inert dusts with products when being bagged or loaded? If DE is admixed, will handling machinery have to be adapted? Will purchasing companies accept the dust or its residues? For structures, can a slurry formulation be used to minimise dust? What time is available for achieving pest control? Which types of DE would be most suitable and effective? What types of IPM systems or co-treatments are feasible? What are the costs and profitability of this system compared to other options? Availability Products are available in some countries, such as Australia, Canada and USA. Suppliers and specialists Examples of specialists and suppliers of products and services are listed in Table See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Note that some DE products (such as Dryacide, Insecto, PermaGuard D10 and Protect-It) are formulated for grain and grain insects, while others are targeted at other types of insects. 148

161 Table Examples of specialists and suppliers of products and services for inert dusts Type of equipment or service Inert dusts different formulations for stored products and structures Specialists, advisory services and consultants Organization or company ARBICO, USA CR Minerals Corp, USA (Diafil) Dryacide Australia Pty Ltd, Australia (Dryacide) Eagle Picher Minerals Inc, USA (Crop Guard) Entosol, Australia (Dryacide) Green Spot Ltd, USA Harmony Farm Supply, USA Hedley Technologies Inc, Canada (Protect-It) JT Eaton & Co Inc, USA Natural Insect Control, Canada Natural Insecto Products, USA (Insecto) Nature s Control, USA Nitron Industries Inc, USA Organic Plus, USA Peaceful Valley Farm Supply, USA PermaGuard Inc, USA (PermaGuard D10) Pristine Products, USA (Perma Guard D10) White Mountain Natural Products Inc, USA WholeWheat Enterprises, USA (PermaGuard D10) Canadian Pest Control Association, Canada CSIRO Stored Grain Research Laboratory, Australia Entosol, Australia Grain Marketing Production and Research Center, USDA-ARS, USA Dr Jonathan Banks, Pialligo, Australia Mr Barry Bridgeman, Grainco Australia Ltd, Australia Dr Paul Fields, Cereal Research Station, Agriculture and Agri-Food Canada, Canada Dr P Golob, Tropical Products Institute, UK Dr Zlatko Korunic, Hedley Technologies Inc, Mississauga, Canada SM Lazzari, institute, Brazil Note: Contact information for these suppliers and specialists is provided in Annex 6. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 149

162 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide Phosphine and other fumigants Advantages General technique and pest control approach akin to MB fumigation. Effective against a broad range of pests including rodents. Fumigants diffuse well in commodities to reach pests. Phosphine is available worldwide. Some fumigants provide rapid treatments. Fumigants can provide a direct replacement for MB in some situations. Disadvantages Phosphine involves long treatment time compared to MB. Like MB, fumigants provide no on-going protection against pests after the treatment. Fumigants can only be used in the countries and for the commodities and situations for which they have been registered. Fumigants are highly toxic, requiring trained personnel, special safety precautions and equipment. Like MB, fumigants can leave undesirable residues in commodities or affect the quality of certain commodities or materials. Technical description Fumigants are toxic chemicals that act against pests while in a gaseous state, though they may be applied in liquid or solid formulations (Bond 1984, Price 1985, Stark 1994). They have relatively low molecular weight and are generally capable of diffusing rapidly through commodities and buildings to reach infestations. Fumigants are highly toxic to humans, other mammals and insects. Their use is generally controlled under regulations covering pesticides, hazardous substances and occupational health and safety. Properly conducted fumigations are complex procedures that should be carried out only by trained fumigators in situations where they are able to work to high safety standards. In applying a fumigant, the aim is to ensure that a certain concentration of gas is kept in the commodity or space for sufficient time to kill the target pests. The appropriate concentration, exposure time and manner of application will depend on a number of factors including those listed below (ASEAN 1989, Graver and Annis 1994, MAFF 1999): Nature of infestation (e.g., pest species, stage of life cycle, position in structure). Nature and quantity of commodity and commodity packaging or nature and volume of structure. Temperature and humidity of commodity and treatment areas. Degree of sealing. Wind velocity. Potential for undesirable residues, corrosion or other undesirable effects in commodities, structures and contents of structures. Properties of the fumigant. Measures for ensuring adequate distribution of the gas. Necessary safety precautions for operators, site staff and the public. Monitoring systems. Fumigants approved for such purposes can be very effective for pest management and disinfestation for official QPS purposes. Fumigations can be carried out in commodities or structures enclosed in gas-tight sheets or in places (such as silos, buildings, ship

163 holds, gas-tight shipping containers and specially designed chambers) provided the required gas concentrations can be maintained for sufficient time to kill pests. When applying phosphine to a bag stack, for example, the stack is covered with gas-tight fumigation sheets and sealed around the base with sand snakes or similar devices. Tablets of aluminium phosphide are placed within the enclosure, releasing phosphine gas. After the necessary treatment period (5 to 15 days), the stack is aerated and the sheets removed. Fumigants control the pests present in the commodity or structure at the time of fumigation, but they do not provide on-going protection against pests. Thus, it is necessary to use some other protective measures or to refumigate after three to six months. Phosphine is the only fumigant other than MB that is registered in many countries for disinfestation of durable commodities. Sulphuryl fluoride is registered in several countries for structures and a few other applications. Other fumigants have very limited registration, and are described briefly below. Phosphine Phosphine (hydrogen phosphide or phosphorus trihydride, PH 3 ) is a colourless gas with a characteristic odour. It is used extensively for durable commodities, principally stored cereals and legumes, and is approved for some quarantine applications (Table 6.7.5). Normally phosphine is generated from solid formulations of aluminium phosphide (e.g., pellets, tablets or sachets) that decompose on contact with water vapour in the air to release phosphine gas inside the fumigation enclosure. Adequate temperature and humidity are required; the equilibrium relative humidity produced by the commodity should be more than 30%. Solid formulations based on magnesium phosphide release phosphine faster and can be used at lower temperatures, e.g. 5 C. More recently developed phosphine-generating equipment, such as the Horn generator, has allowed rapid production of phosphine gas on site and is being used in several countries, including Chile and Argentina (Horn 1997, Horn and Luzaich 1998, Kawakami 1998). Phosphine gas in pressurised cylinders as a 2% phosphine mixture with carbon dioxide propellant is widely used in Australia, and a similar formulation is in the process of registration in the USA (Winks 1990, Winks 1993, Mueller 1998). Phosphine with nitrogen gas in cylinders has been developed in Germany (Böye 1998). When phosphine is supplied as a gas it can be released at lower temperatures, and doses can be precisely administered. For phosphine, a commodity temperature of at least 15 C is recommended, but certain pests are susceptible down to 5 C with long exposures (MBTOC 1998). Effective exposure periods are typically 5 to 15 days, depending on the temperature, target species and developmental stages of pests. Use of phosphine supplied as a gas may allow a slight reduction in the treatment times. Phosphine has the following characteristics: Good penetration into stored products (better than MB). Effective against a broad range of insect pests, although resistance has developed in several species. Disperses well in enclosed spaces. Rapidly disperses on ventilation after fumigation. Can leave residues in food commodities or affect marketable qualities in certain cases (e.g., taint and colour change in walnuts). Generally no negative effects on the germination of treated seeds. Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 151

164 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 152 Forms an explosive mixture with air if the concentration exceeds 1.8% by volume at normal atmospheric pressure; this level is not reached in normal fumigation practice. Reacts with noble metals, such as copper, silver and gold, corroding items such as electric cables, electrical equipment, telephones, sprinkler heads and computers. Measures can be taken to avoid or lessen these effects (Brigham 1998, Brigham 1999, Mueller 1998). Insect populations can develop resistance to phosphine relatively easily (Chaudhry 1997) due to problems such as insufficient treatment times and low concentrations caused by leaky enclosures. Presently resistance can be managed by longer exposure periods and improved gas-tightness. Important steps for resistance management are described in Taylor and Gudrups (1997). Codes of practice and descriptions of the application methods for phosphine for durable products can be found in many sources (ASEAN 1989, Banks 1986, Bond 1984, Degesch America 1997, Graver and Annis 1994, GTZ 1996). New phosphine formulations and techniques are also outlined in numerous documents (Taylor and Harris 1994, Reichmuth 1994, Agriculture and Agri-Food Canada 1996, Horn 1997, Horn and Luzaich 1998, Mueller 1998, Fields and Jones 1999). Sulphuryl fluoride Sulphuryl fluoride or sulfuryl fluoride (F 2 SO 2 ) is an inorganic, colourless, odourless gas supplied as a liquid in pressurised cylinders. In several countries, including the USA, Sweden and China, it is registered for specific uses, such as structures where food is not present or wood products. It is used primarily to kill termites and wood-damaging insects in structures, such as residences and non-food facilities, and is suitable for wood and wood products. It is approved in some countries as a quarantine treatment for certain non-food durables (Table 6.7.5). Sulphuryl fluoride requires a short fumigation period of approximately 24 hours and has a 6- to 8-hour aeration period (MBTOC 1998). Application rates are determined by factors such as target pests, their life stages, temperature at the pest site, volume of fumigation space, degree of sealing/leakiness and target exposure period. High doses (up to 10 times the normal rate for adult termites) are required to kill the egg stage of many insects and can lead to high chemical residues (Bell et al 1998, Taylor et al 1998). Longer exposure periods and good sealing techniques allow for use of lower doses. The characteristics of sulphuryl fluoride include the following: Volatilises readily, giving good penetration and distribution. Effective against a broad range of pests. Short treatment time (similar to MB). Faster aeration than MB. Low sorption to materials. No objectionable odours or colours in treated materials. Does not react with materials normally found in structures. Non-flammable. Not registered for use where food, feed and medicinal products are present, because it can leave residues; permitted residue levels (food tolerances) have not been established. Descriptions of the procedures for using sulphuryl fluoride in structures can be found in DowElanco (1995) and treatments for quarantine in USDA-APHIS (1998). Other fumigants Fumigants that have been used commercially and are available and registered in certain countries include the following: Carbon bisulphide or carbon disulfide (CS2) is used in parts of Australia and

165 China for small lots (about 50 tonnes) of grain in farm storage. It was once widely used as a fumigant for bulk and bagged grain, but application to large bulk storage is limited by the potential fire hazard. In most countries its use has been discontinued and registration has lapsed. Carbon dioxide (CO 2 ). Refer to information on Controlled and modified atmospheres in Section 6.4. Ethyl formate (C 3 H 6 O 2 ) is now restricted to dried fruit and processed cereal products. It was formerly used as a grain fumigant, but registration has lapsed in most countries. It acts rapidly (Hilton and Banks 1997) but is highly sorbed by commodities. Adequate distribution can be difficult. Ethylene oxide (C 2 H 4 O) is used in some countries to reduce microbial contamination in food commodities such as spices, and provides insect control coincidentally. It was widely used for insect control on grain and dates in the past, but has been withdrawn in many countries because it is carcinogenic in animal tests and can produce potentially carcinogenic residues (NIEHS 1991). It is more appropriate for non-food uses such as artifacts and archive materials (MBTOC 1998). Ethylene oxide is flammable, so it is normally supplied in mixtures with inert diluents such as carbon dioxide or HCFCs. Hydrogen cyanide (HCN) is currently registered in a few countries for specific uses, such as treating aircraft in France. It was previously widely used as a fumigant for durable commodities, mills and other structures. It provides a rapid treatment against rodents, where permitted. It can be lethal to humans by skin absorption alone at the concentrations Table Physical and chemical properties of various fumigants compared with MB Carbon Carbon Methyl Sulphuryl Properties dioxide bisulphide bromide Phosphine fluoride Chemical formula CO 2 CS 2 CH 3 Br PH 3 F 2 SO 2 Molecular weight Boiling point ( C) Specific gravity (air = 1.0) Physical description Colourless, Colourless Colourless Colourless Colourless odourless gas or pale liquid, and odour- gas with odour odourless sweet ether- less gas like fish or garlic gas like odour Flammability rating: Non- Flammable Flammable in Flammable Non- 0 = none/very low flammable 3 presence of 4 flammable 4 = high 0 high-energy 0 ignition sources 1 Toxicity Toxic at high Highly toxic Highly toxic Highly toxic Highly toxic concentrations gas gas gas gas Occupational 9000 mg/m 3 3 mg/m 3 Varies from 0.4 mg/m 3 20 mg/m 3 exposure limits (time- in USA in USA 20 mg/m 3 in in USA in USA weighted average) USA to 1 mg/m 3 in the Netherlands Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures Compiled from: data sheets in Annex 3 153

166 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide normally used (Bell 1998). International Codex Alimentarius limits for hydrogen cyanide residues in grain and flour have lapsed due to lack of government support. In-transit fumigation Where regulations permit, fumigation of bulk and bagged commodities can take place on board ship while commodities are in transit. In-transit carbon dioxide treatments are carried out on groundnuts exported from Australia. In-transit fumigation with phosphine is a well-developed technology (Davis 1986, Leesch et al 1978, Redlinger et al 1979, Semple and Kirenga, Zettler et al 1982) but requires ships of appropriate design and stringent safety precautions (Snelson and Winks 1981, IMO 1996). In this method the slow action of phosphine does not interfere with the flow of trade through export ports and thus presents a feasible alternative to some rapid on-shore MB treatments (MBTOC 1998). Table Comparison of suitability of MB and various fumigants for grain Situations where fumigant Situations where fumigant Fumigant may be suitable is not suitable Carbon dioxide For storage of more than 15 days, especially long-term storage Where freedom from residues is valued Where other fumigants are not accepted by markets Where a rapid kill of rodents is desirable Where treatments are carried out close to work areas and habitations Methyl bromide Phosphine When a treatment must be completed in 4 days or less; in this situation, rapid alternatives such as heat and pressure should be examined When it is the only treatment allowed by quarantine authorities In well-sealed systems When a treatment time of 7-16 days is feasible When treating seeds which will be germinated eventually When Trogoderma granarium is present To avoid residues by repeated MB fumigations When the treatment must be completed in less than 15 days In enclosures that are not well sealed Where Trogoderma species are present When seed viability and germination are important When there is no trained, qualified fumigation team On seed required for planting or malting In poorly sealed enclosures On commodities that are very absorbent or contain fat/oils, e.g., expeller cake, oilseeds and oily nuts On commodities previously fumigated with MB (residue problem) Where there is no trained, qualified and properly protected fumigation team In areas immediately adjacent to workspaces and habitations If inadequate sealing or treatment time will not allow control of resistant insects At temperatures below 15 C (although there are exceptions) When treating flour, fishmeal, cottonseed, linseed When there is no trained, qualified and properly protected fumigation team In areas immediately adjacent to works areas and habitations Compiled from: ASEAN

167 Combination treatmens To overcome some of the disadvantages of traditional fumigants, a combination of heat, phosphine and carbon dioxide has been developed (McCarthy 1996, Agriculture and Agri-Food Canada 1996, Mueller 1996, 1998). Carbon dioxide at high pressure is used to treat beverage crops, nuts and spices (Gerard et al 1988, Prozell and Reichmuth 1991, Prozell et al 1997). Current uses Phosphine is registered in most countries and widely used for bulk and bagged grain and other durable commodities, such as herbs, spices and tobacco. It is also used for fumigating wooden objects, paper and other durable materials of vegetable origin. Sulphuryl fluoride has been used for many years in the USA, principally to control wooddestroying termites in structures (Table 6.7.3). Use of other fumigants is restricted to the countries and commodities/uses for which they are officially permitted or registered for use as pesticides. Products Stored grains and legumes worldwide Grains in Australia Variations under development Carbonyl sulphide is being considered for registration for durables, including timber (MBTOC 1998, Banks et al 1993a, Plarre and Reichmuth 1996, Zettler et al 1998). Other potential fumigants under investigation include cyanogen, methyl isothiocyanate, methyl phosphine, ozone, and propylene oxide (MBTOC 1998, Griffith 1999). New formulations of phosphine are being tested to overcome normal phytoxicity to perishable comodities (Kawakami 1999). The manufacturer of sulphuryl fluoride is investigating the possibility of extending the registration to cover food commodities and other uses (Chambers and Millard 1995, Schneider and Williams 1999). Additional work is being conducted to develop combination treatments. Table Examples of commercial use of fumigants Export grains, where permitted Groundnuts exported from Australia Dried fruits, peanuts and tree nuts in USA Dried vine fruit in Australia and South Africa (at time of packing) Exports of cotton seeds, coconut products, handicrafts and other durables from the Philippines Tobacco disinfestation in USA and many countries Disinfestation of logs in USA Wooden products from Malaysia, the Philippines and Vietnam Wood products and artefacts exported from China Buildings infested with termites in USA Fumigants Phosphine Phosphine gas with carbon dioxide propellent In-transit phosphine treatment In-transit carbon dioxide treatment Phosphine Ethyl formate Phosphine Phosphine Sulphuryl fluoride Phosphine Sulphuryl fluoride Sulphuryl fluoride Compiled from: MBTOC 1998, Mueller 1998, Taylor et al 1998, UNDP 1995 Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 155

168 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 156 Material inputs Fumigant. Gas-tight enclosure, e.g., gas-tight fumigation sheets with tear resistance, UVresistance and low weight. Application equipment appropriate for the fumigant formulation. Safety equipment, e.g., respiratory protection. Monitoring devices, e.g., fumigant gas detector. Factors required for use Sufficient temperature and humidity for the fumigant to work effectively. Sufficient sealing and treatment time to kill pests and ensure that pest resistance does not increase. Fully trained fumigation personnel. Robust system of safety practices and monitoring. Pests controlled Fumigants, like MB, can control a wide range of pests. Some are approved as quarantine treatments for specific pests/commodities (Table 6.7.5). Phosphine With sufficient temperature and adequate exposure period, phosphine is effective in controlling major stored product pests, such as confused flour beetle, granary weevil, Indian meal moth, khapra beetle, lesser grain borer, Mediterranean flour moth, rice weevil, rust-red grain beetle and saw-toothed grain beetle (MBTOC 1998). Table shows the treatment times for various pests. As indicated in the table, phosphine is highly effective against all stages of khapra beetle (Trogoderma granarium) in grain, but this treatment has not been approved for quarantine purposes (Bell et al 1984, 1985, MBTOC 1998). Phosphine is effective in controlling bark beetles, wood-wasps, longhorn beetles and platypodids at 15 C or more, but it is not typically effective against seed-infesting nematodes (MBTOC 1998). The tolerance of the developmental stages of insects to phosphine varies considerably. Eggs and pupae are much more tolerant of phosphine than larvae or adults, so fumigation must be continued long enough for the more tolerant eggs and pupae to continue their development to larvae and adults (ASEAN 1989). Control of mite eggs is difficult, but for certain commodities control can be achieved by carrying out a second fumigation after the eggs have been allowed to hatch (an interval of 2 weeks at 20 C or 6 weeks at 10 C) (Bowley and Bell 1981). Information on phosphine s efficacy against pest species and life stages can be found in Phillips (1998). Sulphuryl fluoride Sulphuryl fluoride is effective against major insect pests of timber, including bark beetles, wood-wasps, longhorn beetles, powderpost beetles and dry wood termites, and pests commonly found in structures such as wooddestroying beetles, furniture and carpet beetles, clothes moths, cockroaches and rodents (MBTOC 1998). It is toxic to the post-embryonic stages of insects, but the eggs of many species are tolerant especially at low temperatures. Information on the efficacy of sulphuryl fluoride against a range of pest species and stages is provided in Bond and Monro (1961), Kenaga (1957), Mizobuchi et al (1996), Reichmuth et al (1996), Thoms and Scheffrahn (1994), Dow Agrosciences. Carbon dioxide Refer to information given in Section 6.4. Other factors affecting use Product quality Phosphine can leave residues in food products and can taint certain commodities such as walnuts, herbs and spices. Normal formulations of phosphine are phytotoxic to perish-

169 able commodities. Phosphine is less phytotoxic than MB to seeds, so it can be used where germination is important. Sulphuryl fluoride does not normally affect the quality of materials found in structures, but leaves residues in food commodities. Suitable products and uses Fumigants must only be used for the commodities and uses for which they have been officially permitted, and pesticide registration authorities should be able to provide up-todate information relating to your country or state. Fumigants can be effective in bulk bins, silos, bags, stacks, chambers, structures and transportation, provided sufficient sealing and exposures can be achieved. Phosphine is effective for a wide range of grains and durable commodities including oilseeds, expeller cake, meal, flour and seeds for germination and wooden items. It is also suitable for structures in cases where corrosion will not be a problem. Sulphuryl fluoride is suitable for structures that do not contain food or feed, as well as vehicles, railcars, furnishings and non-edible durable commodities, such as timber, wood products and artifacts. Examples of some approved quarantine uses are given in Table Suitable climates and conditions Fumigants can generally be used in temperate to tropical climates. However, temperatures of more than 15 C are desirable for phosphine use, while relative humidity greater than about 30% is necessary for aluminium phosphide use. Toxicity and health risks Fumigants are by nature highly poisonous. They pose acute toxicity risks if mis-handled, and some pose chronic health risks. (Toxicity data sheets are given in Annex 3.) The occupational Permissible Exposure Limit (PEL) for phosphine is 0.3ppm (0.4 mg/m 3 ) in the USA. Chronic poisoning symptoms from significant exposure include anemia and potentially fatal pulmonary edema, while exposure to higher concentrations can cause renal and liver failure, coma and death (NTP 1990). Table Minimum treatment time for phosphine fumigation of various stored product pests (a) (all stages) Pest species Common name Minimum exposure period (b) C C Acanthoscelides obtectus Dried bean beetle 8 days 5 days Caryedon serratus Groundnut borer 10 days 8 days Cryptolestes pusillus Flat grain beetle 5 days 4 days Ephestia cautella Tropical warehouse moth 10 days 5 days Lasioderma serricorne Cigarette beetle 5 days 5 days Oryzaephilus surinamensis Saw-toothed grain beetle 3 days 3 days Sitophilus granarius Grain/granary weevil 16 days 8 days Trogoderma granarium Khapra beetle 5-10 days (c) (a) Based on a phosphine concentration of 1.0 g/m 3 in gas-tight conditions (b) At temperatures of 30 C or more, many species are controlled by a 4-day exposure. (c) At temperature above 15 C. Compiled from: MBTOC 1998 Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 157

170 Table Approved quarantine treatments for durable commodities examples from USA (USDA-APHIS) Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 158 Commodities Fumigants Typical duration (a) Wooden items with wood borers Phosphine 72 hours Wooden items with wood borers Sulphuryl fluoride 24 hours Wood products, containers with termites Sulphuryl fluoride 24 hours Tobacco for export Phosphine 96 hours Cotton, cotton waste and cotton products Phosphine 120 hours in bulk against boll weevil etc. Bales of hay Phosphine 72 hours Non-plant articles infested with ticks Sulphuryl fluoride 24 hours Seeds of cotton, packaged or bulk Phosphine 120 hours Seeds and dried pods, okra, kenaf, etc. Phosphine 120 hours (a) Duration of treatment can vary according to temperature and dose. The occupational Permissible Exposure Limit for sulphuryl fluoride is 5 ppm (y mg/m 3 ) in the USA. Chronic exposure to significantly higher levels than the PEL may result in fluorosis of teeth and bones, while short-term inhalation exposure to high concentrations may cause respiratory irritation followed by pulmonary edema, numbness and central nervous system depression (NTP 1990). The toxicity of sulphuryl fluoride to mammals by inhalation is similar to that of MB (Bond 1984). The emissions of fumigant gases after treatment can pose safety risks to staff and neighbouring communities. Some fumigant formulations are flammable. Safety precautions for users Handling of fumigants requires full safety training, safety equipment and implementation of appropriate management and emergency procedures. Occupational safety authorities have set exposure limits and can provide guidance on safety procedures and equipment for registered fumigants. Fumigants should only be handled by fully Compiled from: USDA-APHIS 1993, 1998 trained personnel. Other safety controls and requirements include: Respiratory protection. Detailed safety equipment. Training and licensing. Personal monitors. Regular medical check-ups. Fumigant chemicals should be stored in appropriate conditions in special locked areas. Information on safety procedures can be found in HSE (1996a, 1996b) and IMO (1996). Residues in food and environment Fumigants leave residues in food products. Unless precautions are taken, phosphine tablets or pellets can leave powdery residues on commodities that are likely to contain unreacted metal phosphides (MAFF 1999). The Codex Alimentarius Commission of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) has established maximum residue limits for some fumigant residues in specific foods. Residues are also generally controlled under pesticide residue regulations at national or state levels.

171 Ozone depletion The fumigants in this section are not known to be ODS. However, carbon disulfide has been noted as a catalyst for ozone depletion if the gas reaches the upper atmosphere (WMO 1991). Global warming and energy consumption Fumigants described in this section are not known to be greenhouse gases, except for carbon dioxide. Like MB, the products consume energy during their manufacture and transport. Some formulations consume energy during use. Other environmental considerations After a fumigation has finished, the unused gases are released to the air, contributing to local air contamination. Some durable commodities will desorb or slowly release fumigants for a long period after fumigation. Waste from solid phosphine formulations can be a source of environmental pollution; it is normally deactivated in water and detergent and then placed in landfill sites. Large cylinders containing fumigants are normally re-used. Acceptability to markets and consumers Phosphine is widely used for food commodities and well accepted by supermarkets and purchasing companies. Sulphuryl fluoride is likewise well accepted by customers for structural treatments and non-food commodities. Consumers in general do not like chemical treatments for food products, however, and there is increasing public concern about safety issues for communities near fumigation sites. Registration and regulatory restrictions All fumigants have to be registered as permitted pesticides for specific commodities and uses. Phosphine is registered in many countries, while the other fumigants are registered in some cases. Registration may be the responsibility of the government authorities that control pesticides and, in some cases, the authorities responsible for food, grain and quarantine. The storage, sale, use and/or transportation of fumigants are often restricted by regulations on hazardous substances and occupational safety and may also be restricted by local by-laws. In-transit fumigations are subject to shipping regulations and codes of the International Maritime Organisation (IMO 1996). Cost considerations Phosphine generally requires less equipment than does MB, but the chemical products often cost more than MB. In Zimbabwe, for example, the chemical costs were approximately US$ 0.14 per tonne of grain for phosphine, compared to about $ 0.09 for MB. In Indonesia the chemical cost was about US$ 0.20 to 0.29 for phosphine and about $0.09 for MB. For six months of grain storage in Indonesia, the equipment and operating costs were about US$ 0.61 to 0.79 per tonne for phosphine, compared to $ 0.50 for MB (Sidik 1995, Miller 1996). For six months of grain storage in the Philippines, the total fixed and variable costs were about US$ 7.17 per tonne for phosphine and about $ 6.30 per tonne for MB (NAPHIRE 1995, Miller 1996). When longer phosphine treatment is involved, additional fumigation sheets may be required, and those additional sheets add to costs. In Zimbabwe, for example, each additional sheet would cost approximately US$ 2,330 (Miller 1996). The chemical cost of sulphuryl fluoride is higher than MB, for example, about US$ 0.75 to 1.37 per ft 2 for sulphuryl fluoride compared to $ 0.69 to 1.37 for MB for eliminating drywood termites in a large commercial structure (EPA 1996). Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures 159

172 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 160 Questions to ask when selecting the system Which pest species and life stages are present? What level of pest control needs to be achieved? What time is available to conduct the treatment? Can improved sealing or a combination of a fumigant with another treatment, such as heat, reduce treatment times? What is the temperature and humidity of structures and commodities? Which fumigants are effective in these conditions? Is the fumigant registered for this commodity/use? What degree of sealing is necessary? What other regulatory restrictions are placed on fumigant use and storage? Will customers or supermarkets be concerned about residues or quality changes? Type of equipment or service Phosphine-generating products and equipment What safety management systems, safety equipment and training are required? What other equipment and materials are required? What are the costs and profitability of this system compared to other options? Availability Phosphine is available in many countries. The other fumigants are available only in the countries where they are registered. Suppliers and specialists Examples of specialists and suppliers of fumigant products and services are given in Table See Annex 6 for an alphabetical listing of suppliers, specialists and experts. See also Annex 5 and Annex 7 for additional information resources. Information about fumigant products and services can also be obtained from local agrochemical and pest control suppliers and from national pesticide registration authorities. Table Examples of specialists and suppliers of products and services for fumigants Organization or company (product name) Adalia Services Ltd, Canada Ag Pesticides (Private) Ltd, Pakistan (Agtoxin) Beyer (M) Sdn. Bhd., Malaysia Casa Bernado Ltda, Brazil (Gastoxin, Phostek) Degesch America Inc, USA (Phostoxin, Magtoxin) Degesch de Chile Ltda, Chile (Horn generator) Detia Degesch GmbH, Germany (Phostoxin) Excel Industries Ltd, India (Celphos) Fumigation Service and Supply Inc, USA Gardex Chemicals, Canada Hoechst Far East Marketing Corp, Philippines MC Solvents Co Ltd, Thailand Pawa International Sales Agency PL, Thailand PT Elang Laut, Indonesia PT Petrokimiya Kayaku, Indonesia PT Sarana Agropratama, Indonesia continued

173 Type of equipment or service Phosphine + carbon dioxide and phosphine + nitrogen mixtures Sulphuryl fluoride manufacturers Fumigation services (contract services) In-transit phosphine fumigations (contract services) Fumigation sheets and enclosures Safety equipment Specialists, advisory services and consultants Table continued Organization or company (product name) SGS Far East Ltd, Thailand United Phosphorus, India (Quickphos) Westco Agencies (M) Sdn. Bhd., Malaysia BOC Gases, Australia CIG Ltd, Australia (Phosfume) CSIRO Stored Grain Research Laboratory, Australia (Siroflo, Sirocirc) Cytec Canada Inc, Canada (Siroflo, ECO2FUME) Fumigation Services and Supply Inc, USA (ECO2FUME) S&A GmbH, Germany (Frisin) Dow AgroSciences, USA (Vikane, ProFume) Note: This fumigant is registered in only a few countries Fumigation Services and Supply Inc, USA Food Protection Services, Hawaii, USA Igrox Ltd, UK Pest Control Services Inc, Philippines S&A GmbH, Germany SCC Products, USA SGS Far East Ltd, Thailand SGS Far East Ltd, Thailand International Maritime Fumigation Organisation, UK Austral Cathay, Australia Commodity Storage, Australia GrainPro, USA Haogenplast, Israel Power Plastics, UK PT Abdi Ishan Medel General Trading, Indonesia PT Sarana Utama Jaya, Indonesia Refer to government authorities responsible for occupational safety and to pest control product suppliers. Department of Agriculture, Bangkok, Thailand ASEAN Food Handling Bureau, Malaysia Canadian Grain Commission, Canada Canadian Pest Control Association, Canada Central Science Laboratory, York, UK Cereal Research Centre, Agriculture and Agri-Food Canada, Canada CSIRO Stored Grain Research Laboratory, Australia Department of Stored Products, The Volcani Center, Israel Fumigation Service and Supply Inc, USA GTZ, Germany Food Protection Services, Hawaii, USA Home Grown Cereals Authority, London, UK (procedures for phosphine) HortResearch, Natural Systems Group, Ruakura, New Zealand Insects Limited, USA Institute of Plant Quarantine, Ministry of Agriculture, Beijing, China Section 6: Alternative Techniques for Controlling Pests in Commodities and Structures continued 161

174 UNEP Sourcebook of Technologies for Protecting the Ozone Layer: Methyl Bromide Type of equipment or service Table continued Organization or company (product name) Instituto de Tecnologia de Alimentos, Campinas SP, Brazil National Postharvest Institute for Research and Extension, the Philippines Natural Resources Institute, UK SCC Products, USA Dr Jonathon Banks, Pialligo, Australia Mr Patrick Ducom, Laboratoire Dendrées Stockées, France Dr Paul Fields, Cereal Research Centre, Canada Dr Fusao Kawakami, MAFF Yokohama Plant Protection Station, Japan Dr Geoffry Kirenga, Dar es Salaam University, Dar es Salaam, Tanzania Dr Thomas Phillips and Dr Ronald Noyes, Department of Entomology, Oklahoma State University, USA Dr. Elmer Schmidt, Department of Wood Science, University of Minnesota, USA Dr Bob Taylor, Natural Resources Institute, UK Dr Brad White, University of Washington, USA (timber treatments) Dr Larry Zettler, USDA-ARS, Horticultural Crops Research Laboratory, USA Note: Contact information for these suppliers and specialists is provided in Annex

175 Annex 1 About the UNEP DTIE OzonAction Programme The UNEP Division of Technology, Industry and Economics The mission of the UNEP Division of Technology, Industry and Economics is to help decision-makers in government, local authorities, and industry develop and adopt policies and practices that: Are cleaner and safer. Make efficient use of natural resources. Ensure adequate management of chemicals. Incorporate environmental costs. Reduce pollution and risks for humans and the environment. The UNEP Division of Technology, Industry and Economics (UNEP DTIE), with its head office in Paris, is composed of one centre and four units: The International Environmental Technology Centre (Osaka), which promotes the adoption and use of environmentally sound technologies with a focus on the environmental management of cities and freshwater basins, in developing countries and countries in transition. Production and Consumption (Paris), which fosters the development of cleaner and safer production and consumption patterns that lead to increased efficiency in the use of natural resources and reductions in pollution. Chemicals (Geneva), which promotes sustainable development by catalysing global actions and building national capacities for the sound management of chemicals and the improvement of chemical safety world-wide, with a priority on Persistent Organic Pollutants (POPs) and Prior Informed Consent (PIC, jointly with FAO). Energy and OzonAction (Paris), which supports the phase-out of ozone depleting substances in developing countries and countries with economies in transition, and promotes good management practices and use of energy, with a focus on atmospheric impacts. The UNEP/RISØ Collaborating Centre on Energy and Environment supports the work of the Unit. Economics and Trade (Geneva), which promotes the use and application of assessment and incentive tools for environmental policy and helps improve the understanding of linkages between trade and environment and the role of financial institutions in promoting sustainable development. UNEP DTIE activities focus on raising awareness, improving the transfer of information, building capacity, fostering technology cooperation, partnerships and transfer, improving understanding of environmental impacts of trade issues, promoting integration of environmental considerations into economic policies, and catalysing global chemical safety. Annex 1: About the UNEP DTIE OzonAction Programme 163

176 Sourcebook of Technologies for Protecting the Ozone Layer: Alternatives to Methyl Bromide 164 The OzonAction Programme Nations around the world are taking concrete actions to reduce and eliminate production and consumption of CFCs, halons, carbon tetrachloride, methyl chloroform, methyl bromide and HCFCs. When released into the atmosphere these substances damage the stratospheric ozone layer a shield that protects life on Earth from the dangerous effects of solar ultraviolet radiation. Nearly every country in the world currently 172 countries has committed itself under the Montreal Protocol to phase out the use and production of ODS. Recognizing that developing countries require special technical and financial assistance in order to meet their commitments under the Montreal Protocol, the Parties established the Multilateral Fund and requested UNEP, along with UNDP, UNIDO and the World Bank, to provide the necessary support. In addition, UNEP supports ozone protection activities in Countries with Economies in Transition (CEITs) as an implementing agency of the Global Environment Facility (GEF). Since 1991, the UNEP DTIE OzonAction Programme has strengthened the capacity of governments (particularly National Ozone Units or NOUs ) and industry in developing countries to make informed decisions about technology choices and to develop the policies required to implement the Montreal Protocol. By delivering the following services to developing countries, tailored to their individual needs, the OzonAction Programme has helped promote cost-effective phase-out activities at the national and regional levels: Information Exchange Provides information tools and services to encourage and enable decision makers to make informed decisions on policies and investments required to phase out ODS. Since 1991, the Programme has developed and disseminated to NOUs over 100 individual publications, videos, and databases that include public awareness materials, a quarterly newsletter, a web site, sector-specific technical publications for identifying and selecting alternative technologies and guidelines to help governments establish policies and regulations. Training Builds the capacity of policy makers, customs officials and local industry to implement national ODS phase-out activities. The Programme promotes the involvement of local experts from industry and academia in training workshops and brings together local stakeholders with experts from the global ozone protection community. UNEP conducts training at the regional level and also supports national training activities (including providing training manuals and other materials). Networking Provides a regular forum for officers in NOUs to meet to exchange experiences, develop skills, and share knowledge and ideas with counterparts from both developing and developed countries. Networking helps ensure that NOUs have the information, skills and contacts required for managing national ODS phase-out activities successfully. UNEP currently operates 8 regional/sub-regional Networks involving 109 developing and 8 developed countries, which have resulted in member countries taking early steps to implement the Montreal Protocol. Refrigerant Management Plans (RMPs) Provide countries with an integrated, cost-effective strategy for ODS phase-out in the refrigeration and air conditioning sectors. RMPs have to assist developing countries (especially those that consume low volumes of ODS) to overcome the numerous obstacles to phase out ODS in the critical refrigeration sector. UNEP DTIE is currently providing specific expertise, information and guidance to support the development of RMPs in 60 countries.

177 Country Programmes and Institutional Strengthening Support the development and implementation of national ODS phase-out strategies especially for low-volume ODS-consuming countries. The Programme is currently assisting 90 countries to develop their Country Programmes and 76 countries to implement their Institutional-Strengthening projects. For more information about these services please contact: Mr. Rajendra Shende, Chief Energy and OzonAction Unit UNEP Division of Technology, Industry and Economics OzonAction Programme 39-43, quai André Citroën Paris Cedex 15 France Tel: Fax: Annex 1: About the UNEP DTIE OzonAction Programme 165