Volunteer corn has emerged as one of the most common weeds in Midwest soybean production. It's reemergence as a problematic weed is directly related to rapid adoption of glyphosate-resistant corn and sole use of glyphosate in soybean on soybean for weed control. Volunteer corn can reduce soybean yields up to 40% with densities of 16 plants per square meter. In addition, much of the volunteer corn in the eastern corn belt region of the U.S. also carries a Bt trait for insect protection, since the hybrid corn from which it came from was likely to have Bt traits stacked with herbicide resistance traits. Management considerations for volunteer corn in soybean stem from its competitive effect on soybean yield, but also minimizing exposure of insect pests to Bt insect protection traits to slow development of Bt resistant insects. This presentation will discuss the competitive effects of volunteer corn in soybean, emergence of western corn rootworm beetles from volunteer corn plants, and control options for soybean producers.
