Since the inception of Bt cotton, growers who planted the genetically altered seed have been required to plant conventional cotton in refuges, heretofore seen as necessary to manage insect resistance.
For the 2006 season, that is still the case. But EPA could do away with that requirement as early as 2007 if it approves Monsanto Co.'s request to remove the costly burden from growers.
"We are not encouraging growers to consider this a done deal," Monsanto technical manager Walt Mullins cautions. "EPA will decide if there's strength in this package significant enough to make it happen. â€¦ We are emphasizing our commitment to the current requirements until the process is completed."
Monsanto recently filed the request based on a two-year study in which scientists with the company and with land grant universities collected tobacco budworm moths to determine if they derived from cotton. Not enough of them did to raise concern about resistance developing in tobacco budworms as a result of growing Bt cotton, Mullins says.
The study involved collecting tobacco budworm moths in North Carolina, Georgia, Tennessee, Mississippi, Arkansas and Louisiana during 2004 and 2005 and in Texas during 2005.
In Georgia and North Carolina, the number of tobacco budworm moths that derived from somewhere other than cotton hovered around 90%. In the other states, the average was closer to 10%. However, Mullins says, only one-tenth of a percent feeding on alternate crops is enough to keep resistance in the tobacco budworm at bay for at least 30 years, especially since Bollgard II was introduced this year.
"Finding a moth resistant to two genes would be geometrically different from finding a moth that was resistant to one gene," Mullins says.