The National Corn Growers Association reports that 92 percent of the nation's growers met the insect resistance management requirements for Bt corn in 2003. That's up from 87 percent in the first survey of IRM compliance for Bt corn in 2000.
Adherence to refuge requirements for Bt cotton isn't that high. An internal EPA survey indicated that only 77 percent of cotton farmers were in compliance with the more complicated refuge requirements for cotton containing the Bacillus thuringiensis gene in 2002.
Both figures are astounding, however, when you consider that EPA has no legal authority to compel producers to plant the first acre of conventional corn or cotton in a refuge for the Bt crop.
EPA has forced companies that developed the technology to implement extensive refuge plans as a condition for receiving registration renewals. The companies have gone along because they stand to lose millions, if not billions, of dollars if they can't continue to market the technology.
But nowhere in the law does it say the agency can require resistance management plans, according to representatives of the companies. (Because they deal with EPA on a regular basis, they would rather not be quoted.)
EPA would say the resistance management plans are needed to forestall resistance or help Bt genes remain active against target insect species as long as possible.
The agency is under pressure from environmentalists who claim the onset of resistance in caterpillar insects would make the Bt pesticides organic farmers spray on their crops ineffective. But some cotton entomologists say EPA's hand-wringing over the potential for resistance is overdone.
So much divergence occurs in the susceptibility of target species that it's unlikely resistance will develop anytime soon. Example: The need for oversprays of pyrethroids for bollworms that have proven more difficult to control in Bt cotton.
Ironically, EPA allows southern growers to plant only 50 percent of their corn acres in Bt varieties because of the possibility that corn earworms — the same insect as the bollworm — will develop resistance more quickly from exposure to both Bt genes in corn and cotton.
As corn acreage continues to rise, that puts southern corn growers at a disadvantage, particularly in areas where southwestern corn borers have become more destructive.
EPA's numbers notwithstanding, cotton and corn growers have done a good job of complying with its often-confusing regulations. The agency requires Midwest corn growers to plant a 20 percent non-Bt refuge and ensure every Bt cornfield is located within one half mile of a refuge. Cotton farmers have had the option of planting a 5 percent non-sprayed refuge or a 20 percent sprayed refuge or they can adopt a community refuge plan if they plant 20 rows in the middle of the field when the moon is full.
That's a weak attempt at humor, but cotton farmers have sometimes wondered just what kind of drugs the authors of the refuge plans must be on when they attempted to decipher the rules.
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