Evaluation of corn hybrids expressing Cry1F (Herculex (R) I insect protection) against fall armyworm (Lepidoptera : Noctuidae) in the southern United States

Efficacy of two insect-resistant corn hybrids expressing the Cry1F insecticidal crystal protein of Bacillus thuringiensis var. aizawai Berliner (transformation event TC1507) was evaluated against fall armyworm, Spodoptera frugiperda (J.E. Smith), in three southern U.S. locations. Larval susceptibility was evaluated on Cry1F and nonBt field corn, Zea mays L., plants (V3-V12 and R1-R2 stages) in field plots and laboratory studies. Leaf-feeding injury was significantly less and plant height was significantly greater for hybrids containing Cry1F as compared with nonBt corn hybrids when exposed to natural or artificial fall armyworm infestations. In addition, larval mortality was significantly greater on Cry1F corn hybrids compared with that on nonBt hybrids. These results demonstrate that corn hybrids containing Cry1F represent an effective plant incorporated insecticidal protein management option for fall armyworm. In environments where fall armyworm may exceed damage thresholds and have to be carefully managed with foliar sprays, utilization of Cry1F corn hybrids will allow growers flexibility in planting and an efficient means for managing infestations.