EPA: Controversial pesticide offers little help to soybean farmers

The U.S. Environmental Protection Agency has found that soybean seeds treated with neonicotinoid pesticides produce little to no production benefit for farmers.

Neonicotinoids keep pests at bay by distributing themselves throughout the plant. But beekeepers in Minnesota and other parts of the country say they can harm bees.

According to EPA estimates, farmers use soybean seeds treated with neonicotinoid pesticides on about a third of the acres planted. University of Minnesota researcher Bob Koch said he has seen estimates as high as 60 to 75 percent.

In most situations, treated soybean seeds have no benefit, EPA officials say.

Koch agrees. Given the EPA's conclusion, he said there is no need for widespread use of neonicotinoid-treated soybean seeds.

"They're effective at controlling pests that attack the seeds and the seedlings of the soybean plants," he said. "But over time the concentrations of those insecticides in the plant decreases."

Koch said widespread use of the treated seeds opens the door to other problems, including resistant pests and impacts on water resources and pollinators.

The pesticides also wear off after about 40 days and are no longer effective, he said, so some farmers end up spraying their soybean fields when pests strike.

However, the treated seeds can help when farmers know they're at high risk for early season pests.

"But those pests do not occur on all acres or widespread across the soybean production areas," Koch said. "It's more localized. So they serve a purpose, but definitely not widespread across the landscape."