Cotton growers were first able to take advantage of a “natural refuge” for Bollgard II cotton in 2008. Thus far, they are voicing support for this approach to insect resistance management for cotton worm pests.
“We have been getting feedback from cotton growers that convenience and time savings are big benefits to the natural refuge, along with increased income associated with not having to plant a structured non-Bt refuge, as was the case with the original Bollgard cotton,” said Walt Mullins, Monsanto Cotton Traits Technology Development Manager. “Relying on the natural refuge allows growers to save valuable time during planting and the benefit of increased, more consistent yields from being able to plant Bollgard II fencerow to fencerow.”
Because Bollgard II has two separate genes that work against a wide spectrum of cotton worm pests, planting a structured non-Bt cotton refuge is no longer necessary when using the technology in most areas of the Cotton Belt, Mullins said.
“Cotton growers should be commended for following the original IRM refuge requirements for Bollgard and Bollgard II cotton,” Mullins said. “Because most growers have demonstrated good stewardship over the past 12 years in planting structured refugia for Bollgard and the fact that use of a two-gene product reduces the potential for insect resistance, the EPA has concluded that use of a natural refuge for cotton is appropriate in certain cotton-growing regions of the Belt.”
Gary Respass, a cotton grower in Pantego, N.C., used the 80/20 IRM refuge option for years with the original Bollgard cotton. He likes the natural refuge option and took advantage of it in 2008, planting a big portion of his cotton to varieties with the Bollgard II trait.
“We don’t miss having to plant an IRM refuge one bit,” Respass said. “We were able to speed up our planting this spring by not having to handle multiple cotton varieties and clean out planters between varieties. We also avoided the yield reduction and cost we had come to associate with our refuge cotton.”
Respass estimates that in one recent year his IRM refuge acres across 3,000 acres of cotton cost him in excess of $90,000 in yield loss and the cost of having to spray insecticides to control worms in the refuge cotton. “That’s a sizable amount of money. In a heavy worm year, we can easily save that by relying on the natural refuge.”
David Wildy, a cotton producer in Manila, Ark., also took advantage of the natural refuge for Bollgard II in 2008, with positive results. “Being able to use the natural refuge allows us to plant the cotton varieties we want, instead of having to plant non-Bt cotton varieties on the refuge acres,” the Arkansas grower said. “This saves us some valuable time at planting, and it helps us out with overall management of the farming operation.”
Wildy said using the natural refuge for Bollgard II cotton helped him avoid the higher production costs associated with spraying insecticides for worms on refuge acres, as well as some yield loss to worms.
Another cotton grower — Steve Chapman in west Texas — relied on a natural refuge for his Bollgard II cotton in 2008 and feels it benefited him substantially. “Those worms would nickel-and-dime us to death on our refuge acres,” said Chapman, who farms near Lorenzo, Texas, in Crosby County. “I also think Bollgard II allows us to do a better job with integrated pest management because of its two-gene feature. I haven’t had to spray Bollgard II for worms yet.”
Individual results may vary, and performance may vary from location to location and from year to year. Growers should evaluate data from multiple locations and years whenever possible.
Growers may utilize the natural refuge option for varieties containing the Bollgard II trait in the following states: Alabama, Arkansas, Florida, Georgia, Kansas, Kentucky, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, Virginia, and most of Texas (excluding the Texas counties of Brewster, Crane, Crockett, Culberson, El Paso, Hudspeth, Jeff Davis, Loving, Pecos, Presidio, Reeves, Terrell, Val Verde, Ward and Winkler).
The natural refuge option does not apply to Bollgard II cotton grown in areas where pink bollworm is a pest, including California, Arizona, New Mexico, and the above listed Texas counties.
It also remains the case that Bollgard and Bollgard II cotton cannot be planted south of Highway 60 in Florida, and that Bollgard cotton cannot be planted in certain other counties in the Texas Panhandle. Refer to the Technology Use Guide and IRM Guide for additional information regarding Bollgard II, Bollgard, natural refuge and EPA-mandated geographical restrictions on the planting of Bt cotton.
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