Many growers currently use corn hybrids stacked with Bt and glyphosate-tolerant traits to control corn rootworm and manage weeds. The volunteer corn that emerges the following year is considered a weed problem, but it may be a “safe haven” for corn rootworms.

 

The volunteer corn includes second-generation Bt, which equates to a lower dosage of the Bt gene – enough to stun, but not always eliminate the corn rootworm. Exposing the corn rootworm larvae present in the field to less-than toxic levels of Bt can decrease its susceptibility to the Bt trait. This could potentially foster development of harder-to-control corn rootworm.