Organic Pest Management Strategies in the Midwestern U.S.

Organic production in the Midwestern U.S.A. has increased rapidly in the last ten years. Traditionally, organic farmers utilize a systems approach to pest management that allows for a greater tolerance than conventional counterparts. Crop rotations, sanitation practices, resistant varieties, and existing biological control, along with severe winter weather, have held insect pest populations below economic threshold levels in the Midwest. Recently, however, as organic crop production has expanded, organic farmers have reported certain insect pest constraints in organic production. Insect pest challenges associated with three organic crops in the Midwestern U.S.A. are examined here: soybean [Glycine max (L.) Merr.], squash [Cucurbita moschata (Duch & Poir)] and apple (Malus x domestica Borkh.). Critical challenges associated with organic soybean production include bean leaf beetles [Cerotoma trifurcata (Forster)], primarily as a vector of the seed-staining bean pod mottle virus (BPMV) and other seed-staining fungi such as Cercospora kikuchii and Fusarium spp. Organic soybean seed staining has ranged from 0 to 35% over 6 years of research in Iowa. Organically-approved treatments did not affect C. trifurcata populations but yields have remained competitive, averaging 3.6 Mg/ha. An economic evaluation of food-grade organic soybean production revealed that organic soybeans in 3- and 4-year rotations could return $1160 to 1250/ha compared with $235/ha for conventional soybean grown in a 2-year rotation with corn (Zea mays L.). In organic squash trials, squash bugs [Anasa tristis (DeGeer)] were reduced under fabric row covers without compromising yields. Organic apple production has been optimized with the use of apple scab-resistant cultivars, and integrated approaches, including mating disruption pheromones and granulosis virus for codling moth [Cydia pomonella (L.)], and organic-compliant insecticides for codling moth and plum curculio [Conotrachelus nenuphar (Herbst)]. Despite the many pest management challenges, increasing consumer demand for certified organic crops warrants more aggressive and participatory research around the world.