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Compost and Microbial Disease Suppression

Compost and Microbial Disease Suppression. Allison L H Jack Dr . Eric B. Nelson’s Laboratory Group High Tunnel Workshop 12-8-09. Overview. Biologically based disease management Known mechanisms of biocontrol Pythium suppressive vermicompost & liquid vermicompost extract

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Compost and Microbial Disease Suppression

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  1. Compost and Microbial Disease Suppression Allison L H Jack Dr. Eric B. Nelson’s Laboratory Group High Tunnel Workshop 12-8-09

  2. Overview • Biologically based disease management • Known mechanisms of biocontrol • Pythium suppressive vermicompost & liquid vermicompost extract • How these materials are used for nutrient management • Disease suppression in this system • Conclusions

  3. Example: Pythium spp. (damping off) Post-emergence damping off [www.ipmimages.org]

  4. P. aphanidermatum germinating sporangium sporangium direct asexual zoosporangium zoospores indirect DISEASE vegetative hyphae Germinating oospore oogonium sexual antheridium oospore oogonium [modified from Matthews 1931]

  5. Mechanisms of biocontrol • Single organism: • Antibiosis • Competition for nutrients • Parasitism • Induced systemic resistance • Multiple organism: • Much more complicated!

  6. Zwittermicin A (antibiotic) Bacillus subtilis “Kodiak TM” Antibiosis Pythium zoospore Root surface [Shang et al. 1999]

  7. Linoleic acid Pythium sporangium Enterobacter cloacae Competition for nutrients Seed exudates Cucumber seed Linoleic acid Pythium sporangium [van Dijk and Nelson 2000]

  8. Induced Systemic Resistance (ISR) [Chen et al. 2000] Pseudomonas corrugata Pythium sporangium

  9. Parasitism www.nysaes.cornell.edu/ent/biocontrol/pathogens/trichoderma

  10. Multiple organism biocontrol • Often associated with high microbial biomass and activity • Unclear which organisms are involved and how they interact with each other • Goal: • Understand how disease suppression works in a single system so we can make the practice more effective

  11. Liquid vermicompost extract Solid vermicompost • Soil drench applied when irrigating • High in micronutrients • Can provide comparative levels of suppression with 200 x less compost • Can be freeze dried and reconstituted • Simple feedstock + process control = more consistent product • OMRI listed • Potting media amendment • 5-20% depending on crop

  12. Soil applications - garlic 4 t per acre 8 t per acre 2 t per acre [Rangarajan, Leonard & Jack, ongoing]

  13. Cabbage trials • Organic materials rely on microbial activity to mineralize nutrients and make them plant available - results are temperature sensitive Control 10% VC & BM Blood meal 10% VC [Rangarajan, Leonard & Jack, ongoing]

  14. Vermicompost is added to tops of plug trays, aerated vermicompost extract is piped directly into overhead irrigation

  15. Expensive equipment ($20,000) No shelf life Additives needed Cheap equipment ($250) Long shelf life No additives needed Non-aerated compost extract Aerated compost extract 100 gallon tub Timer Sump pump (circulates 2x a day) sump [ElzingaHoeksema Nurseries, MI]

  16. Zoospore pre-infection events

  17. The Spermosphere cucumber seed Pythium zoospore Seed exudates

  18. Conclusions • Using compost can be a valuable cultural practice for suppressing disease • Scientific understanding is not at a level where we can make predictions for specific composts • Look for composters who closely manage their production process for a consistent product

  19. Acknowledgements Nelson Lab: Mary Ann Karp Eric Carr Monica Minson Ellen Crocker Sarah Arnold Dave Moody Financial support: Department of Plant Pathology and Plant Microbe Biology USDA BARD Knight Institute for Writing in the Disciplines New York Farm Viability Institute NYSTAR Center for Advanced Technology & USDA SBIR Phase I & II (with Worm Power) Organic Farming Research Foundation Organic Crop Improvement Association Andrew W. Mellon Fellowship My committee: Eric Nelson (PPPMB) Anthony Hay (MICRO) AnuRangarajan (HORT) Kathie Hodge (PPPMB) Scott Peters (EDUC) Industry collaborator: Tom Herlihy Worm Power Kent Loeffler – photo credits SBIR Program

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