State wants to contain potato pesticide drift

The Minnesota Department of Agriculture is trying to reduce the drifting of pesticides from potato fields to nearby homes and schools.

Thousands of acres of potatoes are grown in north central Minnesota. A fungal disease called late blight can wipe out the crop, so farmers often apply fungicides every week for three or four months.

The agency is creating best management practices to reinforce the regulations on the fungicide label.

"Labels can be very difficult to read or interpret," said Joe Zachmann, an agriculture department scientist. "Sometimes applicators need reminders about what is on the label."

The new voluntary best management practices will be in place by next spring.

"The drift monitoring and the number of misuse complaints that the Department of Agriculture has received over the years in potato production areas were the genesis for the need for these best management practices," Zachmann said.

There is no evidence potato farmers are failing to follow the regulations required by law when applying fungicides, Zachmann said. Those regulations are on the pesticide label. But Zachmann says the new best management practices will offer suggestions beyond what's required on the label.

The agriculture department plans an outreach effort in the spring to educate farmers and pesticide applicators about the new best management practices.

Drift monitors were set up across north central Minnesota starting in 2006. Many were located near potato fields and the most often detected chemical was chlorothalonil, a common fungicide used to prevent potato blight. Monitoring data showed chlorothalonil was found in two thirds of air samples tested.