Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2004
Publication Date: 9/20/2004
Citation: Adamczyk, Jr., J.J., Gore, J. 2004. Laboratory and field performance of cotton containing Cry1Ac, Cry1F, and both Cry1Ac and Cry1F (Widestrike(R)) against beet armyworm and fall armyworm larvae (Lepidoptera: Noctuidae). Florida Entomologist. 87:4. Interpretive Summary: Research was conducted to determine the development of two common caterpillar pests, the beet armyworm and the fall armyworm, on genetically modified cotton cultivars that contained different types of Cry proteins from Bacillus thuringiensis (Bt), a common soil bacterium. In laboratory bioassays and in field plot experiments, cotton containing the Cry1F type was more active against the beet armyworm and fall armyworm larvae compared to cotton containing only the Cry1Ac type. In the majority of experiments, the addition of Cry1Ac to the Cry1F type had no effect on the biology of the beet and fall armyworm compared to cotton containing only the Cry1F type.
Technical Abstract: The efficacy of transgenic cotton genotypes containing Cry1Ac, Cry1F, and Cry1Ac stacked with Cry1F (WideStrike(R), Dow Agrosciences, Indianapolis, IN) were investigated during 2001-2003 against the beet armyworm, Spodoptera exigua (Hubner) (=BAW), and the fall armyworm, Spodoptera fruigiperda (J. E. Smith) (=FAW), in laboratory bioassays and small experimental field plots. In all experiments, cotton containing Cry1F was more active against BAW and FAW larvae compared to cotton containing only Cry1Ac. In the majority of experiments, the addition of Cry1Ac to the Cry1F genotype had no increased effect on efficacy and certain biological parameters against BAW and FAW larvae compared to cotton containing only Cry1F. Furthermore, the presence or absence of an additive, synergistic or antagonistic effect between Cry1Ac and Cry1F was not observed in these field and laboratory experiments.