2011-Season Update on Monitoring of Resistance to Bt Cotton in Key Lepidopteran Pests in the US

Susceptibility monitoring of tobacco budworm, Heliothis virescens, and bollworm, Helicoverpa zea, for the 2011 cotton field season found no evidence of any change in susceptibility to either Cry1Ac or Cry2Ab in either of these target pests. As has been noted for bollworm in past monitoring results, there was continued evidence of high variation in susceptibility to both proteins, but no evidence that the level of variation has increased.