EPA Backs 7 Plant Pesticides

APO 27.09.97 16:25


Copyright 1997 The Associated Press. All rights reserved.
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By CURT ANDERSON
AP Farm Writer
WASHINGTON (AP) -- In a quiet revolution, the use of genetic science in agriculture has now reached the point where farmers are planting crops that contain the material needed to kill many pests -- all without spraying chemicals.
Foremost among these new varieties are plants with the ability to produce toxins because they contain genes from a common soil bacteria known as B.t. There are numerous kinds of B.t. -- shorthand for Bacillus thurigiensis -- each with the ability to destroy specific kinds of insects.
The Environmental Protection Agency has so far approved seven such plant-pesticides for corn, cotton and potatoes. This year's B.t. corn crop is estimated at about 3 million acres, and dramatically improved yields are projected.
B.t. is an important weapon in the battle by corn farmers against the European corn borer. For cotton farmers, it can help control boll weevils, while potato growers gain protection again Colorado potato beetles.
"It's going to be extremely important to our ability to meet the food demands of the future in environmentally sound ways," said Chuck Johnson, chief of Pioneer Hi-Bred International Inc., the world's largest seed company.
But organic farmers and environmental groups, including Greenpeace and the Sierra Club, say there's a hidden danger: insects may become resistant to B.t. more quickly because of constant high-dose exposure to the plants, destroying B.t.'s effectiveness as a conventional insecticide forever.
Organic farmers say the B.t. sprays, which have been in use for 36 years, are the only effective natural alternative to synthetic pesticides.
"Should we ever lose B.t., our ability as organic farmers to grow quality produce will be in serious question," said Jim Gerritsen, an organic potato farmer from Bridgewater, Maine.
The groups this month filed a petition with the EPA demanding that all B.t. plant-pesticide registrations be canceled and that the agency conduct a thorough study of the impact of allowing such crops. The issue could wind up in federal court.
EPA spokesman Al Heier said the agency regards the petition as a serious one, but he noted that the agency consulted outside panels of scientific experts on the issue of insect resistance before issuing the B.t. registrations.
"Resistance management was the main issue we wrestled with," Heier said.
The key, according to EPA, is that farmers who grow B.t. crops must set aside nearby areas with untreated plants.
On these acres, known as "refugia," the insect pests could grow and reproduce without being exposed to the pesticide plants. Their offspring, the theory goes, would remain sensitive to B.t. -- and when they mate with any insects that have gained resistance to B.t., the little bugs those unions produce would still be sensitive to B.t.
"We feel that's as good a program as you can have," Heier said.
The agriculture industry insists it can manage the resistance issue effectively using these methods. The National Cotton Council, for instance, found in a 1998 survey of B.t. growers that 98 percent of them properly set aside the "refugia" acreage.
In addition, cotton growers in Alabama were able to protect their crop last year using the fewest pounds of pesticides in 50 years, said Frank Carter, pest management manager for the Cotton Council.
"B.t. cotton is one of the most environmentally friendly and economically advantageous crop protection tools ever made available to cotton growers," Carter said.
Still, Pioneer's Johnson acknowledged that the insect resistance concern is a real one that demands close scrutiny as B.t. crops are increasingly used by American farmers.
"We are on the front end of really understanding how to use these things," Johnson said. "We have to be diligent in how we test and evaluate those products so we don't make mistakes."

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