GOING UNDERGROUND: DIGGING UP THE DIRT ON METARHIZIUM-PLANT-PEST INTERACTIONS IN AN ORGANIC CROPPING SYSTEM

Demand for organic feed exceeds supply, resulting in the need to facilitate production while maintaining environmental quality, beneficial processes and natural cycles. Overwintering cover crops in annual crop rotations promote soil conservation and natural enemies of pests, but little is known about cover crop effects on an often over-looked natural enemy - insect pathogens. We are investigating the effects of cover crops and soil characteristics on the novel interactions among the fungus, Metarhizium, an endemic disease-causing organisms of insects and plant-protective plant-associate, with crops and cover crops in an organic corn-soybean-wheat cropping system. Our objectives include: 1) characterize Metarhizium isolates from on-going organic research-station and on-farm experiments; 2) determine the ability of naturally-occuring isolates to form a relationships with cash crops and selected cover crops; 3) determine effects of Metarhizium infection of plants in a model system of corn, Zea mays, black cutworm, Agrotis ipsilon; and Cochliobolus heterostrophus, the causal agent of southern corn leaf blight; and 4) determine the effect of plant-associated Metarhizium on the expression of key defense genes that protect plants from crop pests and diseases. Information from this research will be incorporated into evaluated Extension materials and activities to strengthen the capacity of Extension and other agricultural professionals to serve organic growers, and into undergraduate curricula. This project seeks to improve the efficiency and competitiveness of organic crop producers and those transitioning to organic practices, and to understand the effects of soil management and characteristics, crop rotation and cover crops on biodiversity and plant protection in organic feed-grain rotations.