Do you get weary of trying to keep track of EPA-mandated corn refuge acres for insect management? Many farmers do, but there's worry that some aren't in compliance with the rules at all, jeopardizing the longer-term value of Bt technology.
But help is on its way with what seed companies are calling refuge in a bag or insect protection in a bag. It's a way for farmers to benefit from new seed technology that allows you to meet the EPA standards without planting a special structured area of your field to non-Bt corn.
The first kid on the block to apply for EPA approval is Pioneer Hi-Bred with its Optimum AcreMax 1 (OAM1) insect protection. OAM1 would contain a high percentage of a Pioneer brand hybrid with Herculex XTRA (CRW/CB/LL/GLY) insect protection, and a low percentage of a Pioneer hybrid with the Herculex 1 (CB/LL/GLY) trait, which would serve as the corn rootworm (CRW) refuge.
It would satisfy a grower's CRW refuge requirement in a bag, says Bill Belzer, senior marketing manager, corn. Still, growers would need the required corn borer refuge in a different field, up to a half mile away.
“We don't have registration yet, but we are awaiting word from EPA and are optimistic that we'll have it for planting in 2010,” says Belzer.
Pioneer is also developing Optimum AcreMax 2 insect protection, a single-bag, reduced-refuge solution for both above- and below-ground pests. Upon regulatory approval, this technology is expected as early as 2012.
Other seed companies are also expected to petition EPA for refuge-in-a-bag products.
CURRENTLY, YOU HAVE to plant an in-field or adjacent 20% insect refuge of conventional or herbicide-tolerant corn seed to meet EPA refuge requirements when planting Bt traits — 50% for cotton growing areas. Integrating the refuge requirement into a single bag means there will be a seed mix of rootworm Bt corn and non-Bt corn, with the non-Bt corn likely being 5% or less of the total seeds.
“The issue is under debate on what percent should be non-Bt,” says Bob Wright, University of Nebraska entomologist. “We do have biological data that supports refuge in a bag and that it does work. The debate is over size of refuge and resistance management.”
Remember: The purpose of an insect refuge is to maintain the effectiveness of Bt crops by preventing or delaying insect resistance to the Bt trait. A refuge does just that by allowing targeted insects to feed, mate and reproduce without being exposed to the trait. Without a refuge, insects exposed to Bt corn each growing season over multiple generations will eventually become resistant to Bt proteins.
“The main advantage of refuge in a bag is ease of use for farmers,” Wright says. “And it provides a guarantee that there is, indeed, going to be a refuge.”
And compliance is an issue. “We have a significant amount of non-compliance going on now,” says Ken Ostlie, University of Minnesota Extension entomologist. “That non-compliance jeopardizes the durability of the trait. With refuge in a bag you have 100% compliance.”
Ostlie says a concern growers have with the refuge-in-a-bag idea is that the non-Bt level must be low enough they won't see a yield reduction.
For farmers, the 5% refuge in a bag means not having to stop the planter, clean it out and switch to a non-Bt hybrid — and back again. Also, it won't require that when you use a refuge hybrid in your field that you have to then match the in-plant-protection product's maturities and herbicide tolerances.
“To some extent the verdict on refuge in a bag is mixed,” says Wayne Bailey, Extension entomologist at the University of Missouri. “We're in a wait and see mode. We're not sure how well this is going to work, but it's far superior to non-compliance.”