Response of Helicoverpa Zea to Diet-Overlay Bt Toxins and Cotton Bt Traits Field Performance in Texas and the Mid-South

In recent years Bt cotton traits have experienced increasing incidence of unexpected injury events. Field performance trials have indicated that control failures with Bt cotton traits is highly variable and it is not uncommon for dual-gene Bt cotton to benefit from supplemental insecticide treatments targeting Helicoverpa zea. Additionally, diet-overlay bioassays have demonstrated that resistance to Cry1Ac, Cry1F, and Cry2Ab2 is common, while response to Vip3A indicates high susceptibility with few exceptions.