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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 - PowerPoint PPT Presentation
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Compost and Microbial Disease Suppression
Allison L H JackDr. 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– How these materials are used for nutrient
management– Disease suppression in this system
• Conclusions
Example: Pythium spp. (damping off)
Post-emergence damping off
[www.ipmimages.org]
A. Jack Cornell University 2008
vegetative hyphae
sporangium
germinating sporangium
zoosporangium zoospores
antheridium
oogonium
oogonium oospore
Germinatingoospore
asexual
sexual
direct
indirect
DISEASE
[modified from Matthews 1931]
P. aphanidermatum
Mechanisms of biocontrol
• Single organism: – Antibiosis– Competition for nutrients– Parasitism– Induced systemic resistance
• Multiple organism:– Much more complicated!
Antibiosis
Root surface Bacillus subtilis“Kodiak TM”
Zwittermicin A (antibiotic)
[Shang et al. 1999]
Pythium zoospore
Competition for nutrients
Seed exudates
Cucumber seed
Linoleic acid
Pythium sporangium
[van Dijk and Nelson 2000]
Enterobacter cloacae
Linoleic acid
Pythium sporangium
Induced Systemic Resistance (ISR)
Pseudomonas corrugata Pythium
sporangium
[Chen et al. 2000]
Parasitism
www.nysaes.cornell.edu/ent/biocontrol/pathogens/trichoderma
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
Solid vermicompost
• Simple feedstock + process control = more consistent product
• OMRI listed• Potting media
amendment– 5-20% depending on crop
Liquid vermicompost extract
• 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
Soil applications - garlic
2 t per acre 4 t per acre 8 t per acre
[Rangarajan, Leonard & Jack, ongoing]
Cabbage trials
• Organic materials rely on microbial activity to mineralize nutrients and make them plant available - results are temperature sensitive
Control Blood meal 10% VC
10% VC& BM
[Rangarajan, Leonard & Jack, ongoing]
Vermicompost is added to tops of plug trays, aerated vermicompost extract is piped directly into overhead irrigation
Aerated compost extract
• Expensive equipment ($20,000)
• No shelf life• Additives needed
• Cheap equipment ($250)• Long shelf life• No additives needed
Non-aerated compost extract
sump
[Elzinga Hoeksema Nurseries, MI]
100 gallon tubTimerSump pump(circulates 2x a day)
Zoospore pre-infection events
A. Jack Cornell University 2008
The Spermosphere
Pythiumzoospore
cucumber seed
Seed exudates
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
Acknowledgements
Nelson Lab:Mary Ann KarpEric CarrMonica MinsonEllen CrockerSarah ArnoldDave Moody
My committee:Eric Nelson (PPPMB)Anthony Hay (MICRO)Anu Rangarajan (HORT)Kathie Hodge (PPPMB)Scott Peters (EDUC)
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
Kent Loeffler – photo credits
SBIR Program
Industry collaborator: Tom Herlihy Worm Power