Critics of agricultural biotechnology used the increasing problem with herbicide-resistant weeds to call for tighter regulation of biotech crops.

Rep. Dennis Kucinich, who chaired a House hearing last week on the spread of glyphosate-resistant weeds, says the 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 says.

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

Some resistant weeds can’t 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 active ingredient.

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

Michael Owen, an Iowa State University weed scientist, disagreed with the idea of a seed tax, but he said farmers have to quit relying so heavily on glyphosate to control weeds.

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

Some 93% of the soybeans and 70% of the corn planted this year were of herbicide-tolerant varieties.

Kucinich, D-Ohio, said he plans a second hearing on the issue to hear from USDA officials.

One farmer testified at the hearing. Troy Roush, an Indiana corn and soybean grower, was involved in a legal battle 10 years ago with Monsanto Co. over use of the company’s Roundup-tolerant soybeans. Because of weed problems, he has returned to using conventional seeds and says he is making more money on his crops.

Rep. Aaron Schock, R-Ill, expressed concern that increased regulation of biotech crops could threaten advances in crop production.

“The market controls already in place are more than enough to ensure that farmers are employing the best practices to control herbicide-resistant weeds in their fields,” Schock says.