Henry Pak

328 views

Published on

Published in: Education, Technology, Business
  • Be the first to comment

  • Be the first to like this

Henry Pak

  1. 1. ® Beyond AvoGreen Dr Henry Pak, Toni Elmsly July 2009 Dr Kerry Everett
  2. 2. ® What is AvoGreen ? • AvoGreen® is an IPM system • Sprays applied in response to monitored pest pressure • Response thresholds for each pest • Provides basis for justifying use of pesticides • Saves costs by reducing unnecessary sprays and adds value by increasing packouts • Why the need for change?
  3. 3. Why the need for change? 6.0 5.5 5.0 Export values ($/kg) 4.5 4.0 3.5 3.0 2.5 2.0 1998 2000 2002 2004 2006 2008 Season
  4. 4. Where are we headed? Forecast strong growth in volumes → Develop new markets – target niche/premier markets for higher returns → Produce fruit with all market access Consistent, high QUALITY is a necessity for entry to premier markets
  5. 5. What is Quality? Traditionally → Grade Freedom from rots
  6. 6. What is Quality? In future → √ √ Safety √ Taste √ Healthy √ Sustainability √
  7. 7. What lies beyond? Regulatory Drivers: • ERMA, HASNO, Emissions Trading, Regional Councils Customer Drivers: • Food miles, carbon labels, supply programmes e.g. GlobalGAP, Walmart Sustainability Index GAP = Good Agricultural Practice • Need to look at all aspects of production systems including SUSTAINABLITY
  8. 8. Plugging the GAP Good Agricultural practice • AvoGreen® provides a strong platform to build on • Increased emphasis on justifying use /reduce pesticide inputs where required • Major issue for avocados in New Zealand is copper use
  9. 9. Copper – a dilemma • Heavily reliant on regular copper fungicides to control rots = major quality problem. • Why copper? - Cheap - Effective - No market access issues • But…..
  10. 10. Copper - a dilemma • Copper is a heavy metal. • Ecotoxic in soluble form. • Readily binds to clay particles and organic matter: - Forms insoluble complexes that are tightly bound to soil and very stable → accumulates in soil over time.
  11. 11. Objectives • Establish baseline soil copper levels in avocado orchards • Investigate alternatives to copper for rot control
  12. 12. Soil Survey Procedure • 203 soil samples collected from 165 orchards. • Sampled range of different tree ages. • Measured Total and Extractable copper. • Obtained information on: - Land use history - Historical copper fungicide use - Tree age.
  13. 13. Frequency distribution of total soil copper 25 Median = 68 mg/kg Range = 4 - 541 mg/kg 20 Frequency (%) 15 WBOPDC = 370 mg/kg 10 5 0 12.5 37.5 62.5 87.5 112.5 137.5 162.5 187.5 212.5 237.5 262.5 287.5 312.5 337.5 362.5 387.5 412.5 437.5 462.5 487.5 512.5 537.5 Total copper (ppm)
  14. 14. Previous surveys NZ wide 1999 - 19 orchards: mean 170 mg/kg range 70 – 480 mg/kg Holland and Solomona (1999) Auckland 2002 - 43 orchards: mean 209 mg/kg range 7 - 490 mg/kg Gaw (2002) Australia 2002 (NSW avocados): range 280 - 340 mg/kg Merrington et al (2002)
  15. 15. Regional differences Comparison of standard soil test (Mehlich 3 = extractable) versus total soil copper: •Soil retention is strongly influenced by regional soil characteristics
  16. 16. 600 Far North Whangarei 500 400 Total Cu (ppm) 300 200 100 0 0 10 20 30 40 50 60 70 80 Extractable Cu (ppm)
  17. 17. 600 Far North Whangarei 500 Sth Auckland Western BOP Te Puke 400 Total Cu (ppm) 300 200 100 0 0 10 20 30 40 50 60 70 80 Extractable Cu (ppm)
  18. 18. Productivity • The core question regarding sustainable use of copper is: Does soil copper have an influence on orchard yields?
  19. 19. Total soil copper does not affect avocado crop yield 40 30 Yield 2005 (t/ha) 20 10 0 0 100 200 300 400 500 600 Total copper (ppm)
  20. 20. Soil survey summary • Copper is accumulating in soils. • Average copper levels in avocado soils is lower than previous studies but range is comparable • Strong regional relationships between total copper and extractable copper governed by soil types. • No apparent impact of soil copper on productivity.
  21. 21. Is there an alternative? • 12 orchards • 20 trees in randomised block design • Shirlan, Pristine, Copper, Untreated • 5 single tree replicates • 8 monthly applications • Harvested in November 2008
  22. 22. Spray trial results Treatment % rots P value % efficacy Pristine 33 <0.0001 50 Shirlan 46 <0.0001 31 Copper 49 <0.0001 27 Untreated 67 N=4720
  23. 23. Alternatives summary • Both Pristine and Shirlan more biodegradable than copper • Shirlan is as effective as copper, Pristine is more effective • Either could be used in alternation with copper to reduce soil loadings • But neither registered in NZ
  24. 24. Conclusion • Have to position ourselves for ever increasing customer demands on “quality” • AvoGreen® needs to evolve into a GAP-based system to address sustainability requirements • Workable options for reducing copper use together with ongoing monitoring of soil levels • Continue to rely on copper programmes in the interim
  25. 25. Acknowledgments Funding for this project was provided by MAF SFF and AGA Many thanks to all those growers who participated in the survey and allowed field trials on their properties
  26. 26. Thank you

×