Choosing the Best Refuge Hybrids for Planting with Corn Rootworm Resistant Bt Corn

Abstract

Corn hybrids that have been genetically engineered with the Bt gene for resistance to corn rootworm offer growers in New York an interesting option for control of this pest. These hybrids would eliminate the need for soil-applied insecticides in many corn fields, but also require planting 20% of the area of the field with a non-genetically engineered variety (called a “refuge”) to ensure that Bt-susceptible rootworms continue to predominate in the rootworm population. Finding corn hybrids that are well adapted for refuge plantings will reduce the need for insecticide use in refuges, increase profitability from refuge plantings, and make it more likely that farmers will comply with the refuge requirement. Ideal refuge hybrids would suffer relatively little from corn rootworm damage (either because larvae do not damage them much or because they can regrow roots well and thus recover from the damage) and yet produce many adult rootworms to ensure that the rootworm population remains mostly susceptible to Bt. Our research was designed to identify such ideal refuge hybrids.