1 / 23

What makes a compost disease suppressive?

What makes a compost disease suppressive?. Allison L H Jack Dr . Eric B. Nelson’s Laboratory Group Veg Expo 1-27-10. Disease suppression… What do we know?. Single organism biological control is well understood in specific cases

duy
Download Presentation

What makes a compost disease suppressive?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. What makes a compost disease suppressive? Allison L H Jack Dr. Eric B. Nelson’s Laboratory Group Veg Expo 1-27-10

  2. Disease suppression…What do we know? • Single organism biological control is well understood in specific cases • Suppression of disease by a complex community of microbes is much more complicated!

  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

  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, but not always • Unclear which organisms are involved and how they interact with each other and the pathogen • Goal: • Understand how disease suppression works in a single system so we can make the practice more effective

  11. Effect of suppressive amendment on pathogen populations decrease null increase [Bonanomi et al 2010]

  12. Suppression Index (SI) If negative: negative correlation between factor measured and suppression If positive: positive correlation If zero: neutral Microbiological Chemical Enzymatic [Bonanomi et al 2010]

  13. Predictive factors vary by pathogen species

  14. What is vermicompost? Thermophilic compost Vermicompost Usually follows a hot composting step Worm beds (indoor) Windrows (outdoor) Entire process: ~70 days • Static aerated (indoor) • Windrows (outdoor) • 6-9 months curing • Relies primarily on action of microbes

  15. Vermicomposts can protect plants from disease • Multiple cases documented in scientific literature • But, suppression depends on: • Amendment rate • Type of feedstock • Temperature • Presence of synthetic fertilizers • Potting media substrate

  16. Vermicompost is added to tops of plug trays, aerated vermicompost extract is piped directly into overhead irrigation 2008

  17. 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) 1:60 vermicompost: water ratio sump [ElzingaHoeksema Nurseries, MI]

  18. Zoospore pre-infection events

  19. Conclusions • Vermicomposts can be a valuable cultural practice for suppressing plant disease • Scientific understanding is not yet at a level where we can make predictions for specific composts and specific pathosystems • Consider collaborating with regional researchers to further develop these practices

  20. Acknowledgements Nelson Lab: Mary Ann Karp Eric Carr Monica Minson Hillary Davis 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

More Related