Don't get too excited about the idea of a reduced corn refuge just yet. Most corn growers will continue to plant a standard 20% refuge next year on some portion of their acreage.
You've probably heard that a new trait technology has been approved that reduces refuges in some hybrids to as low as 5%. One reason the registration of SmartStax has been met with enthusiasm is the convenience of the smaller refuge. Keith Porter,Mycogen Seeds agronomy services leader, says non-Bt acres often take a yield penalty if not managed properly.
"The important thing to remember this year is refuge reduction is not refuge elimination,” Porter says. "It is critical that growers continue to plant the refuge that corresponds to each hybrid and trait combination. Most of the hybrids that represent refuge reduction will be available in smaller volumes for 2010, and we will not replace first-generation insect traits overnight. As an industry, we must shepherd this technology to avoid insect resistance and satisfy regulatory requirements.”
SmartStax, a trait platform developed by Dow AgroSciences and Monsanto Company, protects against above- and belowground insects with multiple in-plant proteins. This specific combination of events led the Environmental Protection Agency (EPA) to approve a 5% refuge in Corn Belt states and a 20% refuge in Southern cotton-producing areas (some cotton regions qualify for 5%, so check with your seed dealer for details).
Also in the wings is Pioneer Hi-Bred's refuge-in-a-bag concept. Optimum AcreMax 1 Insect Protection awaits EPA registration but remains on track for 2010 release. Upon approval, this hybrid blend would satisfy only the rootworm refuge requirement—you'll still need a 20% European corn borer refuge.
Syngenta's Agrisure Viptera reduces refuges to 20% nationwide through the use of Vip3A, a new non-Cry protein. It will be available for 2010 planting pending receipt of remaining regulatory and import market approvals.
What worries University of Kentucky entomologist Ric Bessin is that refuge planning is getting more complicated. "It's also hard to make 5% sound critical, but it is,” he says.
Joanne Carden, Monsanto U.S. stewardship strategy manager, says trait providers and the National Corn Growers Association are developing refuge calculators and guides that show examples of refuge configurations.
"Continued compliance assessments will be conducted industrywide that measure growers' compliance to the minimum refuge requirements,” she says. Results will be reported to EPA, and growers who do not comply will risk losing access to the technology.
Industry experts suggest the following recommendations to simplify stacked Bt corn trait refuge planting:
- Plant one common refuge that is void of Bt traits, rather than planting a separate refuge for corn borer and corn rootworm.
- Plant the refuge in the same field as the Bt traits to help meet distance requirements for both corn borer and corn rootworm refuges.
- Know the minimum refuge size for your geography and Bt trait.
- November 2009