Despite local Bt resistance, growers still have options
The development of resistance to Bt Cry toxins by the western corn rootworm is a growing concern, highlighted by the recent confirmation of field-evolved resistance to Cry34/35Ab1 in Iowa (https://www.agriculture.com/crops/corn/why-managing-corn-rootworm-just-became-more-complicated). Across the Corn Belt there are western corn rootworm populations with resistance to multiple Bt Cry toxins expressed in Bt corn. In Illinois, Bt resistance can be found in western corn rootworms from both continuous and first-year cornfields; rotation-resistant populations are vulnerable to Bt resistance.…