Will you and your neighbors who plant Bt corn with rootworm and corn borer resistance pass the EPA test this year on planting the required refuge? 2006 is the year that acreage surveys will be made to determine if the voluntary refuge requirement is being met. If you are good boys and girls, you’ll be able to plant Bt corn with more decision freedom than if you fail the test. What will it be?

The whole issue revolves around protection of the Bt genetics against insect resistance. Insects will develop resistance if Bt corn is their only food choice. However, the agreement between the EPA and biotech seed companies to retain 20% of the acreage to help manage resistance issues is designed to ensure corn rootworms and European corn borers do not become immune to the Bt toxin. This year the EPA will examine the effectiveness of Insect Resistance Management (IRM) plan that you have signed with your seed supplier, as part of the reapproval process for Bt corn.

At Purdue University, Dr. Corrine Alexander says some of her research colleagues have found that 85% to 90% of farmers are observing the refuge requirements, if you only look at acreage on a farm. The compliance rate drops to 72% to 76% when refuge design is taken into consideration.

After telephone and face to face focus group surveys with commercial corn growers in Indiana, Alexander found, “Despite the belief that refuges are beneficial, almost a third of producers say that they would not plant a refuge if it was not required, and another 37 percent are undecided as to whether they would plant a refuge if it was not required. Based on the focus group discussions, one reason producers won’t plant a refuge unless it’s required is the perception that if producers who voluntarily plant a refuge are at a competitive disadvantage to producers who do not plant the refuge. Thus, a voluntary IRM plan will not be sufficient to ensure compliance; IRM plans must be required to ensure compliance.”

While a majority of producers would plant a refuge, because it is either required or a good idea, the design of the refuge becomes the major operational problem. Where should it be, what shape will it be, and how is it going to be planted?

• On average, the adjacent field option is most preferred and the border option is the least preferred.
• The adjacent field refuge takes the least amount of extra time to plant and poses the least amount of difficulty and that the border planting refuge option is rated as taking the most extra time to plant and as the most difficult.
• The second most popular is splitting a planter with both Bt and non-Bt varieties.
• Survey respondents consistently rank the border planting option as the most difficult and taking the most extra time, with the primary advantage of the border planting being the ability to protect nearby crops from pollen drift.

If another alternative were available, which utilized a bag of blended seed, containing 80% Bt genetics and 20% non-Bt corn, it would have some popularity, according to the Alexander research, primarily with producers who had not been planting a refuge: “About a third of the survey respondents said that they would be very likely to choose the seed blend option. More importantly, producers who did not have refuge experience in 2003 were significantly more likely to prefer the seed blend option over the four EPA-approved refuge configurations. This finding suggests that the refuge requirement may be a deterrent for some who are not currently planting Bt crops, and that the seed blend option would eliminate this barrier to adopting Bt crops.”

Obviously, farmers like Bt technology to control corn rootworm and European corn borer. But what have we learned? Alexander says the experience we have with Bt corn has resulted in several lessons:

• Farmers have become educated about the need for a refuge to protect the technology, and all farmers benefit from an Insect Resistance Management plan.
• There is a handful of farmers who do not use Bt technology, because of the requirement to plant refuges and manage the technology.
• If there is a requirement for a refuge, then plenty of simple options should be available to comply with that requirement.

Farmers adverse to the refuge requirements and the need for IRM plans, may be willing to comply if a seed blend was a possibility.

Summary:

With the benefit of technology comes the requirement to be a good steward of that technology, and in the case of Bt corn, farmers need to be part of a team that ensures against insect resistance. There are four approve methods of planting refuges adjacent to Bt corn and giving rootworms and corn borers something else to eat. Insects in those refuges can be the targets of insecticides. Because of field shapes, cropping plans, and other issues, some of those four patterns will work better than others. A fifth idea, of blended seed, may be the most attractive to farmers who have not used Bt corn because of the refuge requirement.

Stu Ellis, U of I