Western Bean Cutworm, <I>Striacosta albicosta</I> (Smith) (Lepidoptera: Noctuidae), as a Potential Pest of Transgenic Cry1Ab <I>Bacillus thuringiensis</I> Corn Hybrids in South Dakota

Abstract

Abstract Injuries caused by the western bean cutworm, Striacosta albicosta (Smith), on transgenic Cry1Ab Bacillus thuringiensis (Bt) corn hybrids were documented and quantified. The western bean cutworm is an emerging or potential pest of transgenic Bt corn in South Dakota. The proportion of ears infested with western bean cutworm larvae in the Cry1Ab Bt corn hybrids were 18–20, 38–70, and 0–34% in 2000, 2003, and 2004, respectively. The Cry1Ab Bt corn hybrids were almost completely free of European corn borer infestations. Untreated conventional corn hybrids were less infested with western bean cutworm larvae but more infested with European corn borer larvae. The proportion of ears infested with European corn borer larvae alone were 33, 58–80, and 8–25% in 2000, 2003, and 2004, respectively. Infestations with western bean cutworm alone were 28, 8–28, and 13–19%, respectively. Proportion of ears simultaneously infested with both western bean cutworm and European corn borer larvae were much lower than sing...