Farmers urged to maintain Bt refuge
Since the first Bt crops were introduced, farmers have had to plant a certain percentage of their acres to non-Bt varieties to help ensure insects did not become resistant to the technology.
“Planting a refuge has been and continues to be a key component of an insect resistant management, or IRM, program,” said Kelly Brunkhorst, the Nebraska Corn Board’s director of research. “It’s been that way since the Environmental Protection Agency approved the first Bt crop in the mid-1990s and is just as important today.”
Bt has been re-registered by EPA, which asked technology providers—seed companies—to step up monitoring and make sure refuges are being maintained.
“There is a concern that as corn prices rise, farmers will be tempted to plant less of a refuge because having that Bt protection on more acres means greater yields,” he said. “At the same time, there are many Bt products that offer different types of protection, so it is more difficult to calculate a proper refuge.”
One tool that can help farmers is a refuge calculator developed by the National Corn Growers Association and all major seed technology providers.
Available for free at website, the calculator includes all Bt product options for different parts of the country and simplifies developing a refuge.
Bt technology involves incorporating natural Bacillus thuringiensis proteins into the plant’s stalks, leaves or roots. This significantly reduces insect damage because Bt proteins are toxic to many crop pests but are harmless to people, which is why Bt proteins have been sprayed on many different crops for decades and are still widely used today.
Having a refuge helps ensure crop pests do not become resistant to Bt proteins, thereby reducing their effectiveness.
“Bt technology is worth a lot, as the different types of Bt protection today keep the plant healthier both above and below ground. This means improved yield potential,” Brunkhorst said. “At the same time, it significantly reduces the amount of insecticides sprayed on corn acres, which saves money and time. Farmers need to maintain a proper refuge to make sure we don’t lose the use of this beneficial technology.”
In the past, seed companies did their own monitoring, and sometimes contracted with organizations like the Association of Official Seed Certifying Agencies (AOSCA) to assess randomly selected customers to monitor IRM compliance rates. This year, however, tech providers came together to contract with AOSCA on a national level and make the program completely independent from the seed companies.
The Nebraska Crop Improvement Association, an AOSCA affiliate, will handle the assessment in Nebraska, Brunkhorst said,with letters going out to farmers beginning in June and phone calls to schedule appointments after that.
The assessment must be completed in person and only takes 10-20 minutes.
“They aren’t looking for any more details than the total acres, how many were planted and how many were left in a refuge for each Bt product,” Brunkhorst said. “Part of the technology agreement includes meeting refuge requirements and providing information on their refuge when asked as part of the compliance program, so we’d encourage farmers to respond and cooperate.”