Efficacy of Pesticides Used on Cocoa

Transcription

1 Efficacy of Pesticides Used on Cocoa Roy Bateman International Pesticide Application Research Consortium (IPARC) Abidjan, 11 December

2 Overview When are pesticides used for cocoa? Recent trends in pesticide use Key issue: older pesticides (esp. insecticides) being banned or withdrawn but how to control the pests? Quo vadis?

3 Pesticide Issues Harmonisation of non-tariff measures 396/2005/EC, Japan MHLW 2006 Risk assessment vs. precautionary approach e.g. 91/414/EEC EC 1107/2009 Implementing responsible (rational) pesticide use and its role in: Good Agricultural Practices Good Warehouse Practices Efficacy and resistance management (IRM) Substituting banned active substances Maintaining diversity of Modes of Action (MoA)

4 We urgently need innovative pest management tools that are: Practical As safe as possible Diverse Evidence-based efficacy

5 Probability of Event Cocoa in Ghana: Risk ranking (WB) Highly probable Probable Occasional Interest rate Negligible Moderate Considerable Critical Catastrophic Capsids Black pod Cocoa price risk Cocoa Exchange rate Smuggling Swollen acreage loss Other pests, diseases, shoot virus Misappropriation weeds, etc. of Input price volatility funds Counterparty risk (i.e., Input supplier, farmer, LBCs) Logistics breakdown Dry spell Policy risk Market regulation risk Remote Bush fire Counterparty risk (CMC) Invasive species

6 Phytophthora: management Greatest potential losses, but low concern with capacity to control disease with cultural methods combined with chemical applications against P. megakarya Now greater MoA diversity with: Copper compounds (FRAC M1) Metalaxyl, benalaxyl (FRAC A1) newly registered carboxylic acid amide (FRAC F5) compounds: dimethomorph, mandipropamid

7 Cocoa Mirids Mirid blast (tree die back) Crop loss estimates (Ghana ann. of about 100,000 T) so they are sprayed with insecticides

8 Cocoa swollen shoot disease Problem inseparably linked to old tree (and possibly old farmer!) issues Substantial breeding and replanting initiatives Previous attempts at chemical control (monocrotophos etc. vs. Pseudococcids) were unsuccessful Spirotetramat (MoA 23) may be promoted soon?

9 Storage insects or residues? Possibly an important source of high residues? Phasing-out of methyl bromide heavy reliance on phostoxin: resistance issues?

10 Pesticides also used: Rodenticides For establishing cocoa herbicides, rarely fungicides insecticides for defoliators & termites

11 Recent trends (Global) for insecticides Elimination of most toxic AIs (EPA / WHO 1 & POP) - but implications for resistance management: A positive consequence of MRL regulation for cocoa farmers as well as consumers Rise esp. in pyrethroids & neonicotinoids Promotion of insecticide mixtures, formulated for OECD reg. standards Ag-chem industry has now developed 28 modes of action (MoA) for chemical insect control with an increasing interest in biorationals

12 Where are they putting their money? Bayer (2012) buys AgraQuest (B. subtilis) & Novozymes (enzymes, biopesticides) BASF acquires Becker Underwood ($1.02 billion): crop-technology, beneficial nematodes, mycopesticides Dow: acquired Mycogen in 1996 DuPont: biorational MoA Monsanto: new agricultural-biologicals division Syngenta: set-up Bioline ; acquires Pasteuria Bioscience (bacterial nematicide)

13 Example: mirid control only 4 major MoA have been widely used starting with BHC in 1950s fumigant action compensated for poor application Currently pyrethroids & neonicotinoids (i.e. only 2 MoA) predominate in Africa

14 Insecticide Mode of Action: 28 ways to kill insects & mites : A key to effective insecticide resistance management Moulting & Metamorphosis Group 18 Ecdysone agonist / disruptor Diacylhydrazines (e.g. Tebufenozide) Group 7 Juvenile hormone mimics JH analogues, Fenoxycarb, Pyriproxyfen, etc Midgut Group 11 Microbial disruptors of insect midgut membranes Toxins produced by the bacterium Bacillus thuringiensis (Bt): Bt sprays and Cry proteins expressed in transgenic Bt crop varieties (specific crossresistance sub-groups) Nervous System Groups 1A & B Acetylcholinesterase (AChE) inhibitors Carbamates and Organophosphates Group 2 GABA-gated chloride channel antagonists Cyclodienes OCs and Phenylpyrazoles (Fiproles) Group 3 Sodium channel modulators DDT, pyrethroids, pyrethrins Group 4A Acetylcholine receptor (nachr) agonists Neonicotinoids Group 5 nachr agonists (Allosteric) [not group 4A] Spinosyns Group 6 Chloride channel activators Avermectins, Milbemycins Group 22 Voltage dependent sodium channel blocker Indoxacarb Non-specific MoA Group 9 Compounds of nonspecific mode of action (selective feeding blockers) Pymetrozine, Flonicamid, etc. Cuticle Synthesis Groups 15 and 16 Inhibitors of chitin biosynthesis Benzoylureas (Lepidoptera and others), Buprofezin (Homoptera) Metabolic Processes Many groups acting on a wide range of metabolic processes including: Group 12 Inhibitors of oxidative phosphorylation, disruptors of ATP Diafenthiuron & Organotin miticides Group 12 Uncouplers of oxidative phosphorylation via disruption of H proton gradient - Chlorfenapyr Non-specific MoA Group 10 Compounds of nonspecific mode of action (mite growth inhibitors) Clofentezine, Hexythiazox, Etoxazole Metabolic processes Group 20 Mitochondrial complex III electron transport inhibitors Acequinocyl, Fluacrypyrim, etc Group 21 Mitochondrial complex I electron transport inhibitors Rotenone, METI acaricides Group 23 Inhibitors of lipid synthesis Tetronic acid derivatives website: Insecticide Resistance Action Committee

15 Photo: GAM Early mirid control with insecticides H H Cl Cl Cl Cl H Cl Cl H H Treatments with insecticides such as HCH (lindane): Long residual contact action Some fumigant activity Broad spectrum HCH withdrawn followed by endosulfan

16 Are we evaluating novel control agents using bad models for testing?

17 % responding Assay issues: moving-on from techniques for organochlorines, OPs, pyrethroids Registration authorities to note! Old end point old chemistry (neurotoxic) biorationals etc. 20 Control mortality Time (days)

18 Photo: PHD Phuoc Engineer s Advice If you can t measure it, you can t control it

19 Pesticides are risky, controversial, but apparently necessary in cocoa Newer compounds: non-neurotoxic slower action more costly How to maintain control of key pests? Assays to screen for new compounds? Better methods of application (especially for those with contact action)

20 Variable cone nozzles - locking-in bad practice? 19 th century technology!

21 Linking Regulation, Research Needs and Farmer Practices in the 21st Century Sharing information on pesticide science Joining up: Field practice (training needs) Policies & residue requirements of consumers R&D needs Emphasising safety issues for producers as well as consumers

22 Messages Joined-up policy making Products must work Application matters! Politique élaboration conjointe Les produits doivent avoir une bonne efficacité L'application est important!