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Some Hail, Others Warn About Genetic Tinkering E-mail
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Sunday, 13 November 2005
Some Hail, Others Warn About Genetic Tinkering


The Washington Times

By Shelley Widhalm

Seventy percent of the food American consumers eat has a genetically engineered ingredient in it, mostly from modified corn and soybean crops, says Galen Dively, professor of entomology at the University of Maryland in College Park.

In the mid-1990s, the agriculture industry commercially introduced four crops to farmers - corn, soybeans, cotton and canola - that, through gene splicing, have become herbicide-tolerant and resistant to the crops' main predator pests.

"It's very easy for [farmers] to use because it comes in a seed. It increases yield, and it's not that expensive," says Mr. Dively, extension specialist for pest management for the Maryland Extension Service in College Park. He holds a doctorate in entomology.

Farmers responded enthusiastically to the new crop varieties, even though the seeds cost more, and rapidly and widely adopted herbicide-tolerant (HT) soybeans and cotton, followed by insect-resistant (Bt) cotton and corn, according to the Economic Research Service (ERS), an in-house research agency of the U.S. Department of Agriculture (USDA).

"It's safer because we're not using a bunch of synthetic pesticides. We're reducing that," says Douglas Tregoning, county extension director of the Montgomery County Cooperative Extension in Derwood.

In 2005, 87 percent of the acres farmers planted with soybeans contained the HT strain, as did 61 percent of the cotton acreage and 26 percent of the corn acreage, as stated in USDA survey data, published on the agency's Web site (www.ers.usda.gov).

The HT strain is resistant to specific herbicides that, if applied at the wrong time of the growing season, can kill the crop along with the targeted weeds. With HT crops, herbicides can be applied once the crops are growing instead of before or when the crops are planted. The most common HT crop is called Roundup Ready and is resistant to glyphosate, which is used on grasses, sedges and broadleaf weeds.

Crops modified to be insect-resistant contain a gene that produces a protein toxic to certain insects. The genes for Bt cotton and corn come from the soil bacterium Bt, or Bacillus thuringiensis, and are spliced into the crops to protect the plants from predators. The bacterium produces more than 60 different kinds of proteins.

"The corn is producing its own insecticide internally," Mr. Dively says, adding that for more than 50 years, Bt, which is benign to animals and humans, has been used in insecticides. "This Bt protein is expressed in the plant at a very high dose," he says.

Bt cotton protects against the tobacco budworm, the bollworm and the pink bollworm caterpillars. Bt corn protects against the European corn borer, which likes to eat the cornstalk, and the corn rootworm.

Fifty-two percent of cotton and 35 percent of corn planted in 2005 was of the Bt variety, according to USDA survey data.

Cotton and corn can be "stacked," meaning two traits, HT and Bt, can be genetically engineered into one plant. In 2005, 34 percent of cotton plantings and 9 percent of corn plantings were stacked, according to USDA survey data.

"The adoption rate depends on the pest," says Jorge Fernandez-Cornejo, agricultural economist with the resource economics division of the ERS. "In some areas, there are no pests, so those farmers don't need to adopt."

Farmers reap benefits from using the modified crops, ranging from an increase in crop yield and time saved, such as from fewer pesticide sprayings, to a decrease in pesticide costs, says Mr. Fernandez-Cornejo, who holds a doctorate in agricultural economics.

"They offer some sort of benefit for the farmer. That's why [farmers] are more willing to spend more on seed," says Kim Kaplan, spokeswoman for the Agricultural Research Service, the principal in-house research agency for the USDA. "They're, in the end, better for their bottom line."

The use of insecticides for cotton, which requires a large amount of insecticide to grow, has decreased by at least 50 percent since Bt cotton was introduced in 1996, Mr. Dively says. However, the number of secondary pests, including some varieties of sucking bugs, have increased, though they are easier to control and cause less damage than the worms, he says.

"We are grateful for some decrease of pesticide use in Bt cotton," says Jane Rissler, senior scientist for the Union of Concerned Scientists' Northwest office. The union is a nonprofit alliance of more than 100,000 scientists and others working toward public policies for a safe environment and healthy food.

"It is really a modest benefit compared to the investment made in biotechnology. ... We have these two traits in four main crops. Frankly, that's not a lot to show for billions in investment over 20 years."

In addition, genetically engineered crops have not intrinsically increased in yield, says Ms. Rissler, who holds a doctorate in plant pathology.

"There are genes that control yield. Genetic engineers have not been able to work with those genes to increase yield," she says. The HT and Bt crops "are higher yielding because they reduce the pests," she adds. "They don't make bigger ears or bolls."

Mr. Dively points out additional possible concerns, such as insects and weeds developing resistance to Bt and HT; the Bt protein eliciting an allergic reaction in people who consume food made from the plants; and the HT gene outcrossing and pollinating with wild plants, making them resistant to glyphosate. Outcrossing is not a problem with corn because it has no native plants close enough to cross-pollinate where transfer is possible, he says.

The consumer has not benefited, either, from genetically engineered crops, such as through reduced costs or more nutritious foods, says Doug Gurian-Sherman, senior scientist with the Center for Food Safety, a nonprofit environmental advocacy organization with offices in Southeast and San Francisco that supports safe food production technologies.

"Genetic engineering sounds very sophisticated, but it's actually a crude science," Mr. Gurian-Sherman says.

Scientists do not know if the spliced genes in crops can interact with other proteins and genes or predict how they will interact, he says.

"When you put new genes into a plant, they can inadvertently turn on a gene that could produce a toxic substance," Mr. Gurian-Sherman says. "It's fundamentally exposing us to proteins and other chemicals that have not been in the food supply before."

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