The National Corn Growers Association submitted formal comments to the U.S. Environmental Protection Agency (EPA) this week to ensure future access and continued success with the use of Bt technology.
In September, the EPA published a proposal to update insect resistance management (IRM) strategies for lepidopteran pests, like corn earworm and fall armyworm. EPA went through a similar process several years ago for corn rootworm.
“The proposal offered what the EPA is calling “complex mitigation strategies” that would directly impact corn growers nationwide, not only in the south,” said Chad Wetzel, a Texas farmer and chairman of NCGA’s Production Technology Access Action Team. “EPA proposed phasing out certain Bt pyramids nationwide. NCGA did not support this for multiple reasons, as it would greatly limit grower seed selection and drastically increase the use of a select few Bt products and therefore increase the risk of resistance development for those traits.”
The EPA also proposed an increase from 5 to 10 percent for refuge in a bag product used across the Corn Belt. NCGA did not support this, as EPA did not provide data or details on how this would impact resistance management for both lepidopteran pests and corn rootworm.
In addition to the complex mitigation strategies, the proposal addressed areas where Bt corn and cotton are planted in the same vicinity. Many of the same Bt traits are used in both corn and cotton. EPA proposed the planting of sentinel plots by Bt registrants in Southern states as a new way to monitor resistance development. NCGA supported the use of sentinel plots but called on EPA to provide much greater detail on the implementation of such a program.
Finally, the EPA proposed mandatory compliance measures for growers who are required to plant a block refuge in the South. NCGA did not support this and instead asked EPA to consider a 20 percent refuge in a bag option for Southern states that would simplify corn planting for growers there.