Evaluating the impact of relay-cropping soybean with a pennycress cover crop (Thlaspi arvense) on the population of soybean aphids (Aphis glycines)

The soybean aphid (Aphis glycines) continues to pose a significant problem for soybean growers in the Midwest, as it can cause significant yield losses of up to 40% and has developed resistance to some insecticides. To address this issue, more sustainable management tactics, such as cultural control methods, are needed. Relay cropping of soybean with a winter cover crop has been identified as a potential way to reduce soybean aphid populations. Pennycress (Thlaspi arvense) is being developed as a new winter cover crop and an oilseed crop. The potential impact of pennycress on soybean aphid populations remains unknown. The aim of this study was to investigate the impact of relay cropping soybean with pennycress on soybean aphid populations. The study was conducted over two years and involved relay cropping two soybean varieties with pennycress or without pennycress in a randomized and replicated design. Aphids were counted on ten randomly selected soybean plants per plot each week to estimate soybean aphid populations. The findings of this study could provide insight into the potential reduction of soybean aphid populations with the use of pennycress as a winter cover crop, which may encourage growers who use corn-soybean rotations to adopt this approach.