Syngenta is currently developing VipCot™, a transgenic insect-resistant cotton that expresses both Vip3A and Cry1Ab toxins. In 2006, trials were conducted throughout the cotton belt to test the efficacy of VipCot™ against tobacco budworm, Heliothis virescens (Fabricius), and cotton bollworm, Helicoverpa zea (Boddie). The efficacy of VipCot™ was compared to that of the conventional variety, Coker 312. VipCot™ provided excellent control of both tobacco budworm and cotton bollworm, suffering little or no square, flower or boll damage. These results indicate the high level of insecticidal activity provided by a stack of Vip3A and Cry1Ab toxins.