Competitive release as an ecological cause of stink bug outbreaks in transgenic Bt cotton in the southeast U.S

Insect-resistant transgenic Bt cotton has, in general, increased yield and reduced insecticide use in cotton production by successfully managing target pests. In the southeast US, Bt cotton provides effective control of Helicpverpa zea and Heliothis virescens [Lepidoptera: Noctuidae]. However Bt cotton has not eliminated all pest problems. Also in the southeast, outbreaks of stink bugs, particularly Nezara viridula and Euschistus servus [Hemiptera: Pentatomidae], on Bt cotton have become increasingly serious, requiring more insecticide sprays compared to non-Bt cotton. Such outbreaks represent significant risks in their potential to erode the economic and ecological benefits of Bt cotton. Understanding the ecological mechanisms driving stink bug outbreaks can improve attempts to predict outbreaks in countries considering the commercial release of Bt cotton. Though insecticide release is likely an important factor in stink bug outbreaks, we hypothesize that release from competition with the target pests also contributes to stink bug outbreaks. In this talk, we will present results from experiments designed to test the effect of interference competition on stink bug growth rate, feeding choice, and oviposition choice.