Effectiveness of Insecticide Oversprays for Control of Bollworm and Stink Bugs on Bt Cotton Technology in the Southeastern USA

In the southeastern USA, the bollworm, Helicoverpa zea, and various species of stink bugs, such as the green stink bug, Acrosternum hilare (Say), the southern green stink bug, Nezara viridula (L.), and the brown stink bug, Euschistus servus (Say), are important insect pests of cotton after initial bloom in the crop.  Despite the protection from 2- and 3-gene Bt cotton, such as  WideStrike, WideStrike 3, Bollgard 2, Bollgard 3, TwinLink, and TwinLink Plus, cotton can sustain yield losses from bollworm under heavy enough pressure, particularly in the 2-gene varieties.  Although 3-gene Bt cotton is significantly more efficacious against bollworm than 2-gene varieties, it is not immune to injury and losses from bollworm.  Because Bt technology provides no control of stink bugs, it is well defined that insecticide use is necessary to protect cotton from the boll-feeding complex of bugs, and the pyrethroid insecticides have been the most effective and widely used materials for many years because they controlled both stink bugs and bollworm escaping control from Bt toxins.  However, recently, there is growing evidence that the pyrethroids are becoming less efficacious on bollworm, potentially compromising the concomitant control of both stink bugs and bollworm with inexpensive pyrethroid insecticides.  Data is needed on the importance of several different insecticides relative to control of stink bugs and/or bollworm.  In other words, what contribution to control of bollworm and stink bugs do each of several different insecticides provide?