On-farm evaluation of a fall-seeded rye cover crop for suppression of soybean aphid (Hemiptera: Aphididae) on soybean

Cover crops offer environmental and agricultural benefits, but adoption remains low. Soybean growers have indicated that the adoption of rye as a winter cover crop would increase, if it was shown to offer suppression of a key soybean pest, the soybean aphid Aphis glycines. We performed an on-farm evaluation of two cropping systems utilized in organic production and reduced-herbicide input production. One system includes a rye cover crop, whereas the other does not. At six and five location-years in Minnesota, A. glycines and predator populations, respectively, were measured and compared between the systems with and without rye. The system with the rye cover crop significantly suppressed A. glycines populations on soybean at five of six location-years. Predators appeared to respond more to prey abundance than to plant diversity. An exposure analysis examining biological control potential revealed no differences between soybean with and without rye at any location-year. Insect control can be added to the multiple benefits of rye winter cover crops.