Potato Agronomist's Forum

Transcription

1 Potato Agronomist's Forum Pukekohe 18 August 2016

2 This publication is copyright to Potatoes New Zealand Incorporated and may not be reproduced or copied in any form whatsoever without written permission. Disclaimer This publication is intended to provide accurate and adequate information relating to the subject matters contained in it. It has been prepared and made available to all persons and entities strictly on the basis that Potatoes New Zealand Incorporated, the Foundation for Arable Research, their researchers, authors and contractors are fully excluded from any liability for damages arising out of any reliance in part or in full upon any of the information for any purpose. endorsement of named products is intended nor is any criticism of other alternative, but unnamed product. Potatoes New Zealand has taken has taken reasonable steps and exercised skill, care and diligence in producing this fact sheet to meet the requirements of growers. However there is no implicit or expressed warranty that the information contained is free from error or omission. Potatoes New Zealand Incorporated does not expressly or otherwise endorse the products promoted in this fact sheet. Neither Potatoes New Zealand Incorporated, the Foundation for Arable Research, nor any of their employees or contractors shall be liable for any cost (including legal costs), claim, liability, loss, damage, injury or the like, which may be suffered or incurred as a direct or indirect result of the reliance by any person on any information contained in this fact sheet. Page 2

3 Biosecurity Nick Pyke, FAR Key points In future some aspects of biosecurity in New Zealand will be managed through a partnership between government and industry (GIA). The cropping industry plan to be part of GIA. On-farm biosecurity is important and a Farm Biosecurity Plan should be developed. If you have any concerns about an unfamiliar weed, pest or disease on your farm, call What is biosecurity? Biosecurity is the procedures or measures designed to protect the population against harmful biological or biochemical substances. It includes pre border, border and post border biosecurity. Pre-border biosecurity is a government responsibility. As an industry we can share our views on pre-border activities with government, but decision making lies with them. The Government Industry Agreement for Biosecurity (GIA) has been developed as the method to manage border biosecurity including readiness and response activities. The GIA is an agreement between government (MPI) and industry with both shared decision making and shared costs. Under the GIA our industry will need to sign the Deed which is the first step to engaging with government to develop an operational plan to address both readiness and response. The operational plan will address what the key risks may be, how it is proposed to respond to these risks in the case of an incursion, what the cost sharing formula may be and where the industry will secure funds from. The cropping industry plan to sign the deed, but may need to develop a new legal entity to do this. The industry has proposed to MPI that the operational activities use a pathway approach to decision making around pests and also that one entity manages the readiness and response activities for a number of the plant based industries. This approach has been favourably received by MPI. Although the cropping industry is not yet a signatory to the GIA the GIA approach was used to very effectively manage a blackgrass weed incursion in Canterbury in 2013 and 2016, and for this year's Velvetleaf and Pea weevil incursions. The final part of the biosecurity is the post border activity. This occurs once a biological organism has established in New Zealand and GIA have agreed it is no longer realistic to eradicate or contain the problem. At this point it becomes the industry or your farm responsibility. This is where you should have a plan in place. Do you have a farm biosecurity plan? The biosecurity risk you can most influence is in relation to your own property. There are many weeds and diseases that you could reduce the risk of establishing on your property if you have a robust biosecurity plan. This could save you significant costs of pest control and also potential markedly increase your productivity. Page 3

4 Management Area Biosecurity Management Refers to pages in the Template Guide. Management Objective Identified Risks Use this table to record the biosecurity management practices you are using on the farm. This part of you FEP is not auditable by the regional council but biosecurity risks should not be ignored. There are well documented instances of pests getting out of control giving farmers ongoing aggravation and cost. Recommended practices There is a biosecurity sign to inform visitors and contractors that the farm has biosecurity protocols. The biosecurity sign requests visitors to report to the management. There is a contact number on the biosecurity sign. There is a designated parking area for visitor's vehicles. There is a designated wash-down area for farm machinery and equipment. The wash-down area has a sump to collect weed seeds and prevent run-off into waterways. The area around the wash down area is inspected every 4 months for unwanted pests. Farm personnel, consultants and regular visitors are aware of the farm biosecurity protocols. Farm contractors are aware of the farm biosecurity protocols. Farm employees are aware of weeds, pests and diseases that are not wanted on the farm. Farm employees know where to report unwanted or exotic pests weeds and diseases if they spot them. Contractors are informed if there are weeds, pests and diseases on the farm which may be a risk for their next clients. All machinery and equipment entering the farm is inspected for soil and plant material and is cleaned down before entering paddocks. Level Page 4

5 Machinery is cleaned down before it leaves the property. Vehicle movements are confined to farm tracks where practicable. All grain and fodder bought for animal feed is certified as being disease free and free of weed seeds. Purchased animal feed is fed out in the same area. This area is regularly inspected for new weeds. All livestock movements on and off the farm are recorded with a stock diary. Newly purchased stock are isolated in a holding paddock for seven days. This paddock is regularly checked for unwanted weeds. Crops and pastures are regularly inspected for unwanted weeds, diseases and insect pests. Crop inspection details are recorded in a crop diary or recording sheet. ProductionWise has this option. There is a containment/extermination plan for unwanted weeds and pests. All new seed is certified or has a seed purity certificate. These records are kept. Bins of seed and grain are covered during transport. Plant propagation material is certified or inspected before it is planted out. All farm personnel and visitors returning from overseas have clean clothing and footwear before going onto the farm. You work collaboratively with neighbours and pest control groups to control the spread of weeds and pests. Key Actions Management changes to reduce environmental risks associated with biosecurity Page 5

6 Soil borne diseases and opportunities to reduce them Jen Linton, FAR Soil Borne Disease Trial Background and methods Soil borne diseases are prevalent in potato crops and often thought to be reducing yield. Due to the wide range of soil borne diseases is often hard to identify how much of a role fungicide is playing in supressing and controlling these diseases. A replicated trial was set up in a commercial crop at Levels, South Canterbury with the cultivar Innovator (planted 12 th October 2015). The aim of the trial wase to evaluate various fungicides either applied to the seed or in furrow to evaluate the control of soil borne diseases. Fungicide treatments were applied directly to the seed tubers as either a seed treatment or an in furrow spray prior to closing over the furrows. Standard crop management was undertaken by the grower for the remainder of the season. At two crop growth stages (full canopy, 14 weeks after planting, and late canopy, 18 weeks after planting), disease assessments were carried out. A final yield assessment was carried out on marketable and unmarketable yield (t/ha). Table 1. Treatments, their active ingredients, their target disease and application method (either applied to the potato seed or in furrow at planting) at South Canterbury in the 2015/16 season. Treatment Active Application method Target diseases* ingredient Nil (control) Monceren pencycuron seed tuber *stem canker, black scurf Monceren + pencycuron + seed tuber + Amistar azoxystrobin in-furrow *stem canker, black scurf, silver scurf Amistar azoxystrobin in-furrow *black scurf, silver scurf Amistar 2 rate azoxystrobin in-furrow *black scurf, silver scurf F15/02 penflufen in-furrow (Experimental) black scurf F15/02 + F15/03 penflufen + Bacillus subtilis in-furrow (Experimental) black scurf, soilborne diseases Nebijin flusulfamide in-furrow *powdery scab Page 6

7 Results Potatoes had been grown in the field 4 years previously and a commercial Predicta Pt test on soil from the area of field used for this trial indicated that the trial site had medium to high risk soil borne diseases. The diseases found in the sampled plants and tubers included Spongospora and tuber powdery scab, Rhizoctonia stem canker and tuber black scurf, Sclerotinia white mould on stems, black leg on stems, and common scab on tubers. Rhizoctonia stem canker and Spongospora diseases predominated, while the other diseases were at very low incidence levels. Nebijin reduced the severity of powdery scab at both assessment timings and this was significant when compared to the nil treatment. ne of the other treatments affected any of the diseases observed in the trial. The different treatments did not affect incidence or severity of several other soil borne diseases. There were no statistically significant differences between the treatments for unmarketable or marketable yields. Mean yield for marketable tubers was 82.8 t/ha. This is only one trial result and different seasons, regions or soils may give different results. Table 2. Treatment effect on potato tuber total yield and marketable yield (t/ha) at Levels, South Canterbury in the 2015/16 season. Treatment Unmarketable yield (t/ha) Marketable yield (t/ha) Nil (control) Monceren Monceren + Amistar Amistar Amistar 2 rate F15/ F15/02 + F15/ Nebijin Mean LSD (P < 0.05), df = Page 7

8 Biofumigants There are many different views on bio fumigant crops for the use of controlling soil borne diseases. The use of biofumigants to reduce soil borne diseases, improve soil quality and improve yields in subsequent potato crops is being investigated. The trial was established on a grower property in Timaru on 30 March The four biofumigant treatments will be incorporated into the soil once they reach suitable development stage (except the fallow treatment), and potatoes (cv Innovator) will be planted a few weeks after incorporation. This seed will be treated with formaldehyde to ensure it is as clean as possible. Treatments include four different cropping options before a processing potato crop: fallow (no crop), forage oats (cv Milton), grazing Radish (cv Graza) and mustard (cv Caliente). Potato crop health will be assessed (each of 32 plots) at emergence, full and late canopy, and at harvest. Yields will be measured only at final harvest, possibly by mechanical harvest (large scale). Planting and crop management in season for all the treatments and the following potato crop will be carried out by the grower and are standard practice. Incorporation of treatments to assess their biofumigation effects will be carried out by the grower and should be similar to what the industry has done in the last few years. The biofumigant crop is due to be incorporated in the upcoming weeks. Results will be available in due course. Page 8

9 FAR/PNZ TPP spray demonstration trials Jessica Dohmen-Vereijssen and Peter Wright, Plant & Food Research Three trials were carried out in potato crops, with one trial in each of three regions: Matamata, Manawatu and Canterbury. Five spray programmes were used in Matamata and Manawatu, and six in Canterbury, plus a no spray control. Treatment plots were 7m long and 4.8m wide (6 mounds). The inner 2 mounds were the datum rows of which 5 m were used for assessments and harvest. Each treatment had six replicates. List of treatments used at the Matamata trial. DDA: Degree days. TPP threshold: 3TPP/trap/week. Code Description 1 S we Standard insecticide programme: Weekly from emergence 2 S wd Weekly insecticide applications from DDA 3 S wt Weekly insecticide applications from 3 TPP/trap/week 4 SX we Weekly - alternating oil and insecticides from emergence 5 XS6 wd Alternating oil and insecticides during first 6 weeks from DDA (after Movento) 6 C Untreated control: insecticide sprays Yellow sticky traps were placed at each edge of the crop (one per edge) and one in the centre of the crop. Traps were collected and replaced weekly. The insecticide spray threshold of 3 TPP/trap/week occurred in the last week of December. The DDA threshold of 980 DD was reached in 1st week in January. Plant assessments were carried out within 3-5 weeks after emergence; within 8-11 weeks after emergence; and within weeks after emergence. Five plants per row in each plot (10 plants/ plot) were assessed. Numbers of TPP adults, nymphs (large, medium and small), and eggs were recorded. Numbers of potato tuber moths, lacewing and hoverfly (adults, nymphs and eggs) were also recorded. A blight score was given for each plant. Matamata results Blight scores did not vary significantly between the treatments. Neither marketable weights nor numbers varied significantly between the treatments. Neither specific gravity nor mean ZC score varied significantly with treatment. Higher relative profit (fewer insecticide sprays and ZC affected tubers) where a spray threshold and an agricultural oil was used (treatment XS6 wd; 5 insecticides + 3 oils vs 15 weekly insecticides Page 9

10 Overall findings from the three regions Zebra chip incidence and severity was greater in Canterbury trial than Manawatu and Matamata. individual spray treatment scored best overall when all assessments were considered. Marketable weight did not vary significantly with spray treatment at all three locations. Zebra chip score did not vary significantly with spray treatment at all three locations. Recommendations Use reduced spray programmes where possible (utilizing Degree days, trap thresholds, agricultural oils). Avoid using broad-spectrum sprays such as OPs or pyrethroids early in the season in order to preserve beneficial insects. Do not re-spray an apparent failure with a product in the same mode-of-action group unless the failure is clearly due to factors such as poor application or timing, etc. Know what your insecticides do (pest and beneficial insects, including Tamarixia). Rotate insecticides: avoid continuous sprays of any one mode-of-action group if you use it less frequently, you can use it for longer! Page 10

11 Future technologies for zebra chip management Gail Timmerman-Vaughan, Plant & Food Research, Lincoln. Zebra chip (ZC) disease is caused by the tomato potato psyllid (TPP) / Candidatus Liberibacter solanacearum (CLso) pest/pathogen complex. TPP was detected in New Zealand in 2006 and by 2008 it was clear that it vectored the causal agent of Zebra chip disease, causing substantial damage to potato crops and their value. In 2013, MBIE funded Plant & Food Research to conduct research to develop a range of approaches to contribute to a multifactor approach to control TPP/CLso. Three areas are being researched: 1. Psyllid sensory cues with the aim of developing technologies such as repellents or lures to assist monitoring or disrupt mating behaviour; 2. Psyllid population genetics with the aim of understanding the relationship of TPP regional population differences and factors leading to crop damage, as well as determining the potential for evolution of insecticide resistance; and 3. The plant response to TPP and CLso to develop knowledge that can contribute to approaches for identifying or breeding resistant or tolerant cultivars. We are nearly half-way into our 6 year research programme and aspects of our research progress will be presented. For further information, contact gail.timmerman-vaughan@plantandfood.co.nz Page 11

12 The effects of crop rotation on soil quality and potato yields Steven Dellow and Sarah Sinton, Plant & Food Research & Jen Linton, FAR Background Over the past decade, potato yields have remained static at around t/ha (Canterbury) and typically yield well below potential. These production levels are increasingly uneconomic for growers. In the seasons, Plant & Food Research monitored a total of 15 crops in Canterbury and found that the main factors limiting potato yields were the presence of soilborne diseases reducing underground root and stem health, and compacted soils restricting root growth and reducing the crop s ability to take up water and nutrients. Current Research To capitalise on these initial findings, a three year nationwide SFF project has been initiated by FAR, to investigate how previous crop history and management influences soil quality and the presence of soilborne disease and thus yield. In the first year, eighteen commercial potato field crops were monitored for yield losses possibly caused by soilborne diseases or reduced soil quality. The crops were in Canterbury (12 fields), Pukekohe (three fields) and Manawatu (three fields). Canterbury crops were planted with either Russet Burbank or Innovator (French fry cultivars), while Hermes, Snowden, Moonlight and were grown in Pukekohe and Manawatu, for either crisping, fresh or French fry market. The PreDicta Pt pathogen detection system (South Australian Agricultural Research Institute) was used to measure soilborne pathogen DNA before planting A shadehouse experiment was also set up to neutralise any seed tuber-borne pathogen effects on soil health. This was carried out by collecting soil from each field and planting it with surface-sterilised seed tubers used in the respective crops. The field crops were monitored for disease at plant emergence, full and late canopy, and disease and yields were assessed at harvest. The shadehouse experiment was assessed once at late canopy. Soil aggregate stability, structural condition, penetrometer resistance and root vigour were measured once in all of the fields. Page 12

13 Key findings to date Average yield (assessed in sample plots) in the 18 monitored crops ranged from 52 to 80 t/ha, and initial analyses have shown evidence of the relative contributions of soilborne disease, cultivar and/or soil quality to crop health differences. Fields (10) which had Spongospora pathogen DNA in the soil had all grown potatoes within the last ten years, whereas those (8) with no or extremely low amounts of DNA had not grown potatoes previously. There was a strong link (p<0.001) between Spongospora soil DNA amounts and the subsequent crop severity of Spongospora disease (possibly also influenced by cultivar), indicating that a soil pathogen DNA test could useful for monitoring this pathogen. All fields developed Rhizoctonia stem canker through the season, with infections being first detected at the time of plant emergence (Figure 1, left). Severity of Rhizoctonia disease was less in the shadehouse-grown plants than in the field crops. This suggests that tuber-borne inoculum may have transferred the pathogen to the field crops (Figure 1, right) Rhizoctonia stem cnaker severity/stem Emergence Late canopy Full can Rhizoctonia stem cnaker severity/stem Field Shadehouse 0 rth Island South Island 0 rth Island South Island Figure 1. Rhizoctonia stem canker severity in the field crops at emergence, full and late canopy (left) and late canopy in the field compared to the shadehouse (left). The green bars represent the same RSC severity data in both graphs for the field crops at late canopy. Page 13

14 Although the six rth Island soils had greater aggregate stability than the South Island soils, they also had greater clay contents and were more compacted. Relative cultivar responses to these soil quality differences across regions could not be compared because different cultivars were grown in each. In most crops, very few roots were seen under the wheel track furrows or below compacted zones. In the rth Island, there were fewer pre-plant cultivation passes, coupled with a lower intensity of disturbance, compared to the South Island. However, possible soil quality degradation caused by cultivation was one of many factors potentially limiting yield, and there was no direct relationship with final yield. Soilborne disease in general was lower in the presence of increased root vigour (influenced by cultivar) and was also lower where soil physical structure was better for root growth. individual yield limiting factor could be singled out as predominantly contributing to yield loss in any of the monitored crops. What's next? Analysis of the Year One information is currently being used to formulate the direction for Year Two, which will focus on: The contribution of seed tuber-borne pathogens to crop performance. Treated and untreated seed will be planted in high and low disease risk fields with adverse or optimum soil physical conditions. The effect of winter crops of Caliente mustard, radish, oats and fallow on subsequent potato crop health. For further information, please contact: Steven Dellow steven.dellow@plantandfood.co.nz Phone: This project is funded through the MPI Sustainable Farming Fund and managed by FAR with support from Potatoes NZ and the McCain Growers' Group. Page 14

15 Precision Agriculture: What s driving variability in potato yield and tuber size? Allister Holmes, FAR By its very nature agriculture is the management of variability. There are essentially two types of variation, the first being variability inherent in the site due to soil texture, slope, aspect etc, which can t be changed, but can be managed. The second is management induced variability of soil ph, nutrient status, compaction, previous crop history etc, which the grower can affect. Yield monitors have been fitted to two potato harvesters, and spatial records of yield variability in fields are being recorded, along with manual digs across these paddocks to measure variations in tuber size. Yield variation is inevitable, and careful analysis of yield maps can be used to identify areas where yield limiting factors are having an effect on the crop performance. Figure 1 Yield monitor results from 14 hectare potato paddock Figure 2 Potato tuber size and yield variation across paddock Yield variation has a direct effect on the return from a potato crop, but the difference in the size profile of the crop can also drive the value of the crop harvested, compounding the financial impact of variability in the paddock. Where to next? w that we have identified variability in potato crops, we are investigating what can be done to maximise the profitability of the crop. We are considering the effect of soil ph, texture and cultivation practices; as well as seeding rate, fertiliser and irrigation on the spatial yield and tuber size of potato crops. Page 15

16 FAR PO Box Templeton Christchurch Potatoes New Zealand Inc PO Box The Terrace Wellington