Volunteer corn presents new challenges for insect resistance management
Genetically-modified (GM) corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] dominate the North American agricultural landscape and are becoming increasingly important as biofuels. However, as herbicide-tolerance and insecticidal traits are often simultaneously expressed by individual plants, glyphosate [N-(phosphonomethyl) glycine]-resistant (GR) volunteer corn is becoming a widespread problem as a weed in corn-soybean rotational systems. We show that these volunteer corn plants not only have herbicide-tolerance genes but also express insecticidal 'Bt' protein. We also report high levels of damage to these plants from larvae of the target pest, the western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte). This suggests that volunteer herbicide-tolerant Bt corn has the potential to present problems both for weed management and insect resistance management, as it may facilitate more rapid evolution of Bt resistance in corn rootworm populations.