Grower questions planting requirements for Bt corn

Q

My seed dealer said it is OK to plant YieldGard Corn Borer hybrid corn as a refuge for my Herculex I Bt corn field because they use Bt proteins with different modes of action. Is this correct?

A

According to the EPA-approved label which outlines requirements for using Bt corn hybrids, the refuge corn must not be a Bt corn active against European corn borer, if the Bt corn hybrid has a Bt protein active against the European corn borer. Remember, the goal of the refuge is to promote survival of European corn borers who have not been exposed to Bt protein, in the immediate area of the Bt corn field. Using a Bt corn active against European corn borer would not be an effective method to allow survival of corn borers in the refuge.

A similar situation exists with Bt corn hybrids active against corn rootworms; three types of Bt proteins are expressed in the Bt corn hybrids of different companies. Using one company’s Bt rootworm corn as a refuge for another company’s Bt corn hybrid, would not be in compliance with the label instructions.

There is a kernel of truth in the original suggestion; in general, using different toxins with different modes of action has the potential to reduce resistance development. In this case however, rotating toxins is not compatible with the goals of the refuge-based resistance management plan that we are using.

Bob Wright
Extension Entomologist

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© 2007 by the University of Nebraska Board of Regents. All rights reserved.

Published by University of Nebraska-Lincoln Extension in the Institute of Agriculture and Natural Resources Cooperating with the counties and the U.S. Department of Agriculture.

The University of Nebraska-Lincoln does not discriminate on the basis of gender, age, disability, race, color, religion, marital status, veteran's status, national or ethnic origin, or sexual orientation.




© 2007 by the University of Nebraska Board of Regents. All rights reserved.

Published by University of Nebraska-Lincoln Extension in the Institute of Agriculture and Natural Resources Cooperating with the counties and the U.S. Department of Agriculture.

The University of Nebraska-Lincoln does not discriminate on the basis of gender, age, disability, race, color, religion, marital status, veteran's status, national or ethnic origin, or sexual orientation.