Scientists, Critics Worry about Insect Resistance

Article excerpt

Although farmers may find insect-fighting crops irresistible, many scientists worry that these bioengineered plants may create almost as many problems as they are designed to solve.

Biotech critics, government regulators and scientists fear that unfe ttered use of these crops will cause insects to develop resistance to the plants' built-in armaments. Then, it's a very expensive trip back to the drawing board.

"Insects are so darned adaptable," said Mike Weiss, professor of entomology at North Dakota State University. "Insect resistance to any control strategy is a real threat." Weiss is chairman of a nationwide group of scientists, government officials and company representatives trying to make sure crop biotechnology's benefits aren't squandered. "Right now, there are so many questions and so few answers," he said. The group has conducted resistance management experiments for several years; it expects to make some recommendations early next year. One key issue is convincing farmers that letting some pests live will extend the effectiveness of gene-altered plants. "Farmers don't like to be told what to do," said Richard Hellmich, a research entomologist for the U.S. Department of Agriculture. "We have to get growers' cooperation so they buy into the idea that they are partners in resistance management." Farmers know that insects fight back. Cotton farmers, for example, have seen several chemicals come and go as pests developed resistance. And even when chemicals work against a pest like the boll weevil, they kill beneficial insects, allowing other pests to flourish. Breaking this chemical cycle is the goal of the companies that implant toxins in crops to kill pests. The key component is Bacillus thuringiensis, a common soil bacterium. BT produces a protein that kills some pests. Yet, it doesn't harm beneficial insects, animals or humans. Critics say the government is granting approvals for BT plants too quickly, accelerating the chance of insect resistance. They say overplanting BT crops will render ineffective the BT insecticides that have been sold for decades to home gardeners and organic farmers. …


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