New Stacked Cotton - No Refuge Requirement
Cotton farmers growing varieties with two Bt genes, such as Bollgard II® and WideStrike®, no longer have to plant a non-Bt cotton refuge to avoid insect resistance, based on new Environmental Protection Agency (EPA) rules. As part of the revamped regulations, however, single-gene Bollgard® varieties, introduced to the marketplace in 1996, must be phased out after the 2009 season. That means single-gene varieties like Delta & Pine Land Company's DP555, popular in the mid-South and lower Southeast, will not be available for the 2010 crop.
The EPA ruling affects growers from Texas eastward. It excludes some counties in the Texas Panhandle, which have not been eligible to use Bt cotton due to the region's large corn acreage resulting in potential resistance with bollworm populations. Monsanto, which makes Bollgard® and Bollgard II®, and Dow AgroSciences, manufacturer of the two-gene WideStrike, cooperated with the National Cotton Council to work with EPA on the new rules. “We offered our data package to Dow to facilitate their effort in obtaining the natural refuge option. It was the result of a five-year, multi-state research project by Monsanto, university and USDA researchers to determine the host crop of adult bollworm and budworm moths trapped in or near cotton fields,” says Walt Mullins, Monsanto's technology development manager. “We were able to discern what crop or plant types the larvae fed upon before they became the moths. By doing this we were able to prove that all cotton fields contained some number of non-cotton-derived bollworm and budworm adults all season.”
That convinced EPA that bollworm and budworm resistance won't likely develop in two-gene Bt cotton and that the natural refuge from other crops or weeds produce enough nonselected moths to provide adequate refuge for resistance management. Single-gene cotton, though, presented a greater risk of insect resistance developing. That's why EPA insisted the original Bollgard® had to be phased out. The new policy also came about after EPA grew concerned that growers were not complying with refuge rules. “Compliance in some states has been declining in the past few years. If this trend in noncompliance continues, EPA may require industry to impose stiffer penalties for noncompliance. This would not be good for industry or the grower," Mullins says.
Duane Canfield, Dow AgroSciences product manager for PhytoGen and WideStrike, says plenty of solid research went into the decision. Dow's WideStrike made its debut in 2005 and is available in its PhytoGen varieties. The company has never sold a single-gene Bt cotton product. By 2010, the three refuge options will be history. The old compliance program, however, which requires farmers to state what they're doing, will still be around. “There's still an EPA compliance requirement and a company requirement. We’re still watching these technologies from an insect resistance management standpoint. There still have to be signed grower agreements, and we will still be monitoring fields,” Canfield says.
It will also call for some adjustments on the part of growers, moving some along to newer varieties. “We do not have a Bollgard II® and Roundup Ready Flex® variety that yields as good as DP555 for the lower Southeast and mid-South. Continued presence of the single-gene product jeopardizes the longer-term viability of the two-gene products. We agreed to terminate the registration of Bollgard after the 2009 season to ensure enough time for good Bollgard II replacement varieties to be developed and offered to the marketplace,” Mullins says. “It takes growers time to adjust not only to new technologies but also to become comfortable that the new varieties will produce the yield and quality they desire,” he adds. (GMO Pundit, 10/10/07).
