Biodiversity and the development of natural pest control

We will examine whether, through time, the adoption of organic farming improves natural pest control. Mixed-vegetable farmers have reported to us that since adopting organic methods, they see fewer aphids and caterpillars on their farm each year. Growers generally attributed this to the gradual buildup of insect-killing predators, parasitoids and pathogens. Improving soil quality, and thus healthier and more insect-resistant plants, could also explain this pattern. Understanding what makes a farm pest-suppressive could ease future farmers' organic transition. Our project will explore the emergence of natural pest control following the conversion to organic farming, by comparing recent adopters to farms that have been organic for decades. Our project includes three integrated research and extension components. The First Component will measure on-farm biodiversity among natural enemies, while searching for management practices associated with species-rich and evenly-balanced assemblages. The Second Component will directly quantify how many pests the natural enemies kill on each farm, in part by searching for pest DNA within predators' stomachs. The Third Component will compare plants' ability to fight-off pests on "new" versus "old" organic farms, in part by measuring the activity of insect-fighting plant genes. Our results and recommendations will be disseminated through an innovative extension program that emphasizes hands-on learning and on-farm demonstration, in addition to innovative web, instruction and publication outlets. The project directly addresses ORG program goals by exploring and understanding the role of biodiversity in organic agriculture systems, to reveal the importance of biodiversity as a benefit of organic agriculture, production, and sustainability.