Field-evolved resistance to Bt maize by western corn rootworm: Predictions from the laboratory and effects in the field

► Iowa field populations of western corn rootworm evolved resistance to Cry3Bb1 maize. ► Root injury to Cry3Bb1 maize was higher than to other types of Bt maize and to non-Bt maize treated with insecticide. ► Survival of western corn rootworm did not differ between Cry3Bb1 maize and non-Bt maize. ► Better IPM tactics are needed to delay Bt resistance in western corn rootworm.