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Proposed Framework to Prevent Corn Rootworm Resistance

Beginning January 28, 2015, EPA is seeking comment on a framework intended to delay the corn rootworm pest becoming resistant to corn genetically engineered to produce Bacillus thuringensis (Bt) proteins, a plant incorporated protectant (PIP). Bt proteins kill corn rootworms but do not affect other wildlife or humans. The proposed framework includes requirements on the manufacturers of Bt corn.

The Agency is open to suggestions for alternative approaches that would achieve the objective of prolonging the durability and effectiveness of these plants to control the corn rootworm pest. If finalized, farmers would have to make some changes in the way they use Bt corn, in order to slow resistance.

Use of PIP crops, including Bt corn, is one of the safest methods of insect control. If used properly, PIP crops greatly reduce the need for conventional pesticides and the risks they may pose to human health and the environment. For these methods to continue to be available long into the future, it is essential that they remain effective.

Public comments on the EPA’s proposed requirements must be submitted by March 16, 2015 to EPA docket EPA-HQ-OPP-2014-0805 at www.regulations.gov.

Read the January 28, 2015 OPP Update on the Proposed Framework to Prevent Corn Rootworm Resistance.

Learn more about the proposed measure to prevent corn rootworm resistance:

  1. How do I know if I am in an area of corn rootworm resistance?
  2. How is EPA proposing to address corn rootworm resistance in Bt corn?
  3. What is the timeline for finalizing the January 2015 proposed revisions?
  1. How do I know if I am in an area of corn rootworm resistance?

    Resistance of corn rootworm to Bt corn has been documented in parts of Iowa and Illinois. However, EPA believes that other parts of the Corn Belt, where corn rootworm infestations are common and the use of Bt corn is high, are also at risk for resistance. These areas are known as the corn rootworm "red zone" and include portions of Iowa, Illinois, Nebraska, western Indiana, southwestern Wisconsin, southern Minnesota, and eastern South Dakota. Other corn-growing regions outside of these states may also be at risk of resistance, though not to the same extent as areas in the "red zone." The Department of Agriculture for each State may have additional information on specific areas of corn rootworm resistance.

    Regardless of geography, if these conditions are prevalent on your farm or in your area, you are likely part of the “red zone”:

    • Corn-on-corn for multiple years
    • Heavy use of Bt corn
    • Regular corn root worm infestations
    • Spotty compliance with current refuge requirements

  2. How is EPA proposing to address corn rootworm resistance in Bt corn?

    EPA has proposed a framework intended to delay the problem of the corn rootworm pest becoming resistant to Bt proteins. The Agency is proposing requirements on the manufacturers of Bt corn including:

    • In areas at risk for corn rootworm resistance, to require crop rotation, use of corn varieties containing more than one Bt protein, or other Integrated Pest Management (IPM)  strategies and stewardship for corn rootworm.
    • To develop and implement a strategy to better detect and address areas of resistance as they emerge.
    • To use different and improved scientific tests and sampling to study the problem and more reliably ensure that resistance to the Bt corn proteins is identified.

    EPA’s proposed framework outlines that 70% of corn acres in the “red zone” should take part in IPM efforts and that 50% of corn acres in non-“red zone” areas should participate in IPM efforts. IPM efforts (e.g. crop rotation) are designed to prevent future problems rather than reacting to them once they occur. These measures and others are designed to significantly delay development of resistance in corn rootworms in areas planted with Bt corn.

  3. What is the timeline for finalizing the January 2015 proposed revisions?

    On January 28, 2015, EPA announced this proposal for a 45-day comment period, ending on March 16, 2015. EPA is seeking input on this proposal from all stakeholders, including corn growers, non-governmental organizations, industry, academia, and the general public. Commenters are encouraged to offer input on specific recommendations, including alternative approaches or counter proposals to address corn rootworm resistance management issues.

    Following review of comments, EPA will finalize appropriate measures to address the issue of corn rootworm resistance to Bt corn.

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