Corn Expressing Cry1Ab Endotoxin for Management of Fall Armyworm and Corn Earworm (Lepidoptera: Noctuidae) in Silage Production

Abstract

Fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea Boddie, perennially cause leaf and ear damage to corn for silage production in the southeastern United States. Transgenic hybrids expressing the Cry1Ab (MON810 event) insecticidal endotoxin from Bacillus thuringiensis (Bt) were evaluated for management of fall armyworm and corn earworm in central Georgia during 2006 and 2007. Hybrids with a temperate or semitropical background were planted at the recommended time in mid-April and in late June to simulate a double-crop corn planting. Whorl infestation and damage by fall armyworm was significantly reduced in hybrids with the Bt trait when infestations were large. Fall armyworm infestation levels and damage were similar in both temperate and semitropical types. Hybrids with the Bt trait also had a small reduction in ear infestation and less kernel damage in ears infested by corn earworm than susceptible hybrids in most trials. Corn earworm infestation level were less in the...