Washington, D.C. – The spread of weeds resistant to Roundup herbicide is bringing new scrutiny to the government’s regulation of biotech crops.

U.S. Rep. Dennis Kucinich, D-Ohio, a longtime critic of the biotech industry, said the U.S. Agriculture Department has been too quick to approve new varieties of herbicide-tolerant crops and other biotech products.

“Now, more than ever, farmers need to have a Department of Agriculture that takes care to preserve and protect the farming environment for generations to come,” Kucinich said during a House hearing he chaired Wednesday on the spread of Roundup-resistant weeds.

One weed scientist, David Mortensen at Penn State University, said the government should restrict the use of herbicide-tolerant crops and impose a tax on biotech seeds to fund research and education programs.

The resistant weeds cannot be killed by the sole use of glyphosate, the active ingredient in Roundup herbicide, which has become broadly popular with farmers with the advent more than a decade ago of soybeans, cotton, corn and other crops that are immune to the chemical. The weeds now infest about 11 million acres, a fivefold increase in three years, Mortensen said.

The problem is most prevalent in cotton and soybean fields in the South but is spreading to other regions. And it will get worse if farmers don’t take measures to control for the weeds, including spraying additional herbicides and alternating chemicals and crop varieties, he and other scientists told a subcommittee of the House Oversight and Investigations Committee.

The Environmental Protection Agency already requires farmers to limit their use of insect-resistant corn and cotton to avoid the development of pests immune to the pesticide the crops contain. Mortensen suggested the government set controls for herbicide-tolerant crops.

Michael Owen, an Iowa State University weed scientist, thinks Iowa is only two years away from a serious problem with glyphosate-resistant weeds. He said farmers have to quit relying so heavily on Roundup to control weeds.

Farmers “value the convenience and simplicity of these crops without appreciating the long-term ecological and economic risks,” he said.

Biotech companies are trying to deal with the problem by engineering new crop varieties that will be immune to more than one herbicide, but even those products will eventually run into resistance problems if farmers aren’t careful, Owen said.