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Corn+Soybean Digest

IRM Refuges A Must For Bt Corn Growers

As growers throughout the Corn Belt work through spring planting season, the National Corn Growers Association (NCGA) encourages all farmers planting Bt corn borer resistant corn to implement insect resistant management (IRM) refuges to ensure they meet the Environmental Protection Agency’s (EPA) IRM requirements. Growers who do not plant proper refuges along with their Bt corn risk losing access to this technology in the future.

For the first time, there may be growers who will be denied access to the Bt technology for the 2005 growing season if they do not meet the refuge requirements again in 2004. Under the Compliance Assurance Program (CAP) — an EPA-approved IRM awareness and compliance program implemented in 2002 — growers who have been found not meeting IRM refuge requirements in two consecutive years, can be denied access to Bt corn borer resistant corn in the third year.

As a CAP requirement, registrants of Bt corn borer resistant corn are responsible for evaluating the extent to which growers are adhering to IRM requirements through on-farm visits and an annual grower compliance survey. Established in 1999, IRM refuge requirements were enacted to help prevent corn insect pests, such as the European corn borer, from developing resistance to Bt technology, enabling the technology to be used well into the future. According to these requirements, growers are obligated to plant at least a 20% refuge, with Bt corn fields located within one-half mile (preferably one-quarter mile) of the refuge. In certain corn/cotton areas of the South, growers are required to plant at least a 50% corn refuge.

“Research confirms that farmers growing the majority of Bt corn acres value the technology and are adhering to IRM requirements,” says Helen Inman, NCGA Biotech Working Group chairman. “As efforts to elevate the importance of IRM and implementation of IRM practices continue to increase, so does grower compliance. Every effort is being made to provide growers with the right information so they can make informed-decisions that result in added value to their business — economic and environmental. We do not want any grower to be deprived of this valuable technology.”

According to the 2003 IRM grower compliance survey, 92% of farmers met regulatory requirements for IRM refuge size, while 93% percent met refuge distance requirements — an increase from 87% and 82% reported respectively in 2000 when the survey began.

NCGA Online Learning Center for IRM
To help support IRM awareness efforts, NCGA recently launched the industry’s first IRM online education center for growers — the Insect Resistance Management Learning Center (IRMLC).

Developed by NCGA and the Agricultural Biotechnology Stewardship Committee (ABSTC) — a coalition of the four Bt corn borer registrants — the IRMLC provides a comprehensive overview on the principles of IRM.

Available free-of-charge at, the IRMLC provides corn growers access to training on several topics, including IRM, Compliance Assurance Program (CAP), Integrated Pest Management (IPM), Corn Borer, and Corn Rootworm. Within each section, users of the IRMLC can complete a series of questions to reinforce their knowledge. Upon satisfactory completion, the user can print out a certificate of completion.

The NCGA also suggests growers consult with their seed dealers and seed company representatives to help ensure they understand IRM requirements. Growers also can visit the “Know Before You Grow” section of for more information on Bt corn and the IRM requirements.

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