Modeling resistance of sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), to transgenic Bt corn

A demographic model was used to study the evolution of resistance by Diatraea saccharalis (F.) (Lepidoptera: Crambidae) to transgenic corn expressing one or two Bt proteins. The effects of biological and agricultural factors on resistance evolution were studied by using sensitivity analyses to improve insect resistance management strategies for D. saccharalis. Increase in the proportion of refuge did not always improve the durability of Bt corn if there were sugarcane, sorghum, or rice in the agro-ecosystem. The evolution of Bt-resistance accelerated when larvae entered diapause for overwintering early. Low frequency inter-field movement of moths delayed the evolution of resistance to single-protein or pyramided-Bt corn when the proportion of refuge was 20%, but it accelerated Bt-resistance evolution when the proportion of refuge was 50%.