Efficacy of Bt maize producing the Cry1Ac protein against two important pests of corn in China

Ostrinia furnacalis (Guenée) and Helicoverpa armiger a (Hübner) are the most important pests of maize in China. A laboratory study and a 2-year field study on the efficacy of transgenic maize expressing the Cry1Ac protein BT38 against O. furnacalis and H. armigera were performed. We found that the husks, kernels, and silks of BT38 showed significant efficacy against larvae of O. furnacalis and H. armigera . In the field, when neonate larvae of O. furnacalis and H. armigera were on plants at different growth stages and when levels of leaf-damage or number of damaged silks were used to score efficacy, we found that BT38 showed significant insecticidal efficacy against O. furnacalis and H. armigera , but the non-Bt maize did not show significant efficacy against either pest. These results suggest that the insecticidal efficacy of Bt maize expressing the Cry1Ac protein could be useful in the integrated pest management of these key maize pests.