2010-04-13
WASHINGTON (Reuters) - Genetically engineered crops are profitable for farmers and may help protect people and the environment from an overload of pesticides, a panel of experts reported on Tuesday.

But there is a risk that weeds are developing resistance to Roundup, a weedkiller that is used to treat fields planted with certain genetically modified crops, the researchers said.

And genetic engineering is not being exploited enough, given its potential benefits, the National Research Council panel concluded.

"We do see good, hard evidence that weed resistance is growing to glyphosate. That needs serious attention," said David Ervin of Portland State University in Oregon, who chaired the panel.

Glyphosate is the main ingredient in Monsanto's widely used Roundup herbicide. The weedkiller is considered safer for people than other pesticides. "It in general replaces more toxic chemicals," Ervin, a professor of environmental studies, said in a telephone interview.

Monsanto also has genetically engineered a range of crops to resist its effects.

That means farmers can use more Roundup without fear of damaging their crops. But the practice may have allowed weeds to develop their own natural resistance, the expert committee found.

Nine weed species in the United States have developed resistance to glyphosate since the introduction of genetically engineered crops, compared with seven in areas where genetically modified crops are not used, the report found.

But in general the use of gene-engineered crops is beneficial, the experts found.

LOWER COSTS, HIGHER YIELDS

"Farmers who have adopted genetically engineered crops have experienced lower costs of production and obtained higher yields in many cases because of more cost-effective weed control and reduced losses from insect pests," reads the report from the Council, one of the independent National Academies of Science that advise the federal government.

"Farmers and their employees not only face reduced exposure to the harsh chemicals found in some herbicides and insecticides used before the introduction of genetically engineered crops but have to spend less time in the field in applying the pesticides."

Ervin said the panel did not address safety or health issues, which were covered in previous reports. "We attempted to navigate a middle ground on this. We were not intending to be pro or con," Ervin said.

Using crops engineered to resist pesticides allows farmers to rely less on tilling the soil, a practice that can reduce soil quality and worsen erosion, the report found.

Other types of genetic modification have also been helpful, the experts found. "Insecticide use has decreased with the adoption of insect-resistant crops," the report reads.

So far, these engineered genes have not spread to the wild to create super weeds, the report found -- at least not in the United States. But the risk remains.

The National Research Council report said that crops engineered for pest control now cover more than 80 percent of the acres planted to soybean, cotton and corn, or almost half of U.S. cropland.

If anything, genetically engineered crops are not used enough, the report said.

"With proper management, genetic-engineering technology could help address food insecurity by reducing yield losses through its introduction into other crops and with the development of other yield protection traits like drought tolerance," it concludes.