A federal U.S. court has ruled in favor of critics of Monsanto Co's genetically engineered sugar beets, saying the U.S. government failed to adequately evaluate environmental and economic risks associated with the crop.

The U.S. District Court for the northern district of California ruled that the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) violated federal law by failing to prepare an environmental impact statement before deregulating genetically altered sugar beets.

Monsanto developed the biotech beets to be resistant to Monsanto's glyphosate herbicide Roundup, and promotes the sugarbeets as "Roundup Ready."

The plaintiffs include the Center for Food Safety, Organic Seed Alliance, Sierra Club, and High Mowing Seeds. The groups filed the lawsuit in January 2008.

About 1.1 million U.S. acres were seeded this year to Roundup Ready sugar beets in the fourth year of commercialized production.

Critics say the Roundup Ready beets are dangerous for the environment because they promote the emergence of "superweeds" or weeds that cannot easily be killed because they also develop a tolerance to weedkiller. They also say that organic and convential beet farmers are damaged because the genetically altered sugar beets are wind-pollinated and inevitably cross-pollinate related crops grown nearby.

The court found that USDA gave only "cursory" consideration to some of these concerns, failing to adequately consider the risks. The court has ordered the USDA to conduct a rigorous assessment of the environmental and economic impacts of the crop on farmers and the environment, and will evaluate other remedies in an October meeting of the parties.