New Bt Stacks Require Review of IRM Guidelines

DES MOINES, Iowa, Feb. 11, 2005 - Growers considering new corn hybrids with stacked Bt technologies should take a closer look at insect-resistance management (IRM) requirements for 2005. Regulations accompanying these products, such as newly available Pioneer® brand hybrids with the YieldGard¹ Plus trait, incorporate compounded guidelines in the U.S.

For example, the YieldGard Plus technology is a stack containing both the YieldGard¹ Corn Borer gene and the YieldGard¹ Rootworm gene. The refuge acreage requirements differ for these two technologies.

"Pioneer brand hybrids with the YieldGard Plus trait have two separate insect-protection genes," said Alex Woodall, product stewardship manager for Pioneer Hi-Bred International, Inc. "Managing two genes can be complex in regard to refuge acreage and location requirements, but it's essential to preserving their effectiveness now and in the future."

Growers can meet IRM requirements through common or separate refuges. In a common refuge, the YieldGard Corn Borer and YieldGard Rootworm traits in YieldGard Plus hybrids are managed as one component. The refuge must be within or adjacent to fields containing the YieldGard Plus traits.

Separate refuges are designed to work independently for each Bt trait. The corn borer and rootworm components of hybrids with the YieldGard Plus traits are managed separately for refuge purposes to allow flexible refuge design. The corn rootworm refuge must be within or adjacent to the YieldGard Plus field. However, the corn borer refuge can be up to a half mile from the YieldGard Plus field.

Corn Belt vs. southern cotton-growing areas
A more complex issue is the various refuge percentages in non-cotton growing areas versus cotton growing areas.

In non-cotton growing areas, up to 80 percent of corn acres in each field can be planted with hybrids that contain Bt corn borer protection or rootworm protection. A minimum of 20 percent of corn acres must be planted with hybrids that do not contain a Bt gene for corn borer protection or rootworm protection.

In cotton growing regions, hybrids with the corn rootworm trait require only a 20 percent refuge. However, hybrids with a corn borer trait require a 50 percent refuge. Thus, using a separate refuge configuration for YieldGard Plus in these areas allows a grower to plant up to 50 percent of a field to hybrids with YieldGard Plus. They can plant another 30 percent of the same field to hybrids containing YieldGard Rootworm technology. At least 20 percent of the field must contain a refuge without either technology.

Although the new regulations may be complex, Pioneer professionals will assist customers in every way possible to help them be good stewards of available technologies.

"Working with customers to ensure the highest possible level of compliance with IRM requirements is a Pioneer mission," Woodall said.

Pioneer requires each grower purchasing Bt hybrids to sign a Pioneer Hi-Bred Technology Agreement. By signing it, the grower agrees to implement the Environmental Protection Agency (EPA) mandated IRM program as specified in the Product Use Guide. Failure to follow these IRM requirements can result in the grower losing access to Bt technology.

Your local Pioneer sales professional can provide complete details on all IRM regulations regarding Bt corn refuge acres for 2005. Product Use Guides for each trait also are available from your Pioneer sales professional or on the Pioneer GrowingPoint(SM) website: .

Pioneer Hi-Bred International, Inc., a subsidiary of DuPont, is the world's leading source of customized solutions for farmers, livestock producers and grain and oilseed processors. With headquarters in Des Moines, Iowa, Pioneer provides access to advanced plant genetics, crop protection solutions and quality crop systems to customers in nearly 70 countries. DuPont is a science company. Founded in 1802, DuPont puts science to work by creating sustainable solutions essential to a better, safer, healthier life for people everywhere. Operating in more than 70 countries, DuPont offers a wide range of innovative products and services for markets including agriculture, nutrition, electronics, communications, safety and protection, home and construction, transportation and apparel.