Transgenic cottons containing the Bollgard®, Bollgard II® and WideStrike® traits were grown in 2005 and 2007 to examine the efficacy against beet armyworm Spodoptera exigua (Hübner) a nd fall armyworms S. frugiperda (J. E. Smith). Results suggest that both dualgene traits are more efficacious against these armyworm species than Bollgard®. In these studies, WideStrike® appears to be more efficacious against fall armyworms than Bollgard II®, while Bollgard II® is more efficacious against beet armyworms than WideStrike®. Possible reasons for these differences in efficacy are discussed.