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Minn. farmers' harvest hit hard by drifting weed killer

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Tom Peterson stands on his farm, near Trimont
Southern Minnesota farmer Tom Peterson, standing on his farm Trimont, Minn., last week, says he suffered a yield loss after dicamba herbicide from a neighbor's land drifted onto his soybean field during the growing season.
Mark Steil | MPR News

Tom Peterson first noticed the shriveled leaves and stunted growth in two of his soybean fields last June. 

"At one point, my beans were about a foot tall and looked like heck," he said. 

But in his neighbor's field, the crop looked fine, Peterson said. "His beans were about two and a half feet tall. I mean it was quite a dramatic change from one field to the next."

The culprit: the controversial weed killer dicamba. When applied to soybeans genetically modified to withstand it, dicamba works as an herbicide. But the problems occur when dicamba drifts to neighboring non-tolerant soybean fields, like Peterson's. Wind may blow it off-target, or the chemical can vaporize and move.   

Now, as farmers finish up fall harvest, crop damage from dicamba is cutting into yields — and profits. More than 200 Minnesota farmers say a neighbor's use of the herbicide dicamba damaged their crops, and it could cost them about $7 million collectively. And many farmers aren't sure if they'll find any compensation for their loss.

"In the farming game the more bushels you have to sell, the much better chance you have of profit," said Peterson. "So, yeah, every bushel lost is a concern." 

Crop consultants believe dicamba drift caused rounded, cupped leaves.
Crop consultants believe dicamba drift caused rounded, cupped leaves on these soybean plants.
Mark Steil | MPR News file

Peterson lost two to four bushels per acre of his soybean crop, a third of what he expected. Still, the dicamba damage hurt, costing him roughly $3,000 lost revenue on just over 100 acres of soybeans.  

Southern Minnesota crop consultant Jim Nesseth said he's seen heavier damage than what Peterson experienced. In some cases, it was between 10 and 12 bushels per acre lost.

The later the dicamba arrived in the growth cycle, the worse the damage, said Nesseth. Dicamba applications in the warmer and more humid conditions of June appear to have caused the most damage.

Even so, Nesseth hopes dicamba can remain an option for farmers because it does a good job killing weeds that have become resistant to other herbicides.

The major makers of dicamba — Monsanto, BASF and DuPont — have agreed to change their application guidelines next year to try reducing the drift problem. The changes include requiring farmers to maintain records of their dicamba use, limiting when and under what sorts of wind conditions the chemical can be sprayed, and mandating that only certified herbicide applicators with special dicamba training apply the herbicide.  

Dicamba has caused problems across the country. The U.S. Environmental Protection Agency says more than 3.5 million acres of crops in 25 states were damaged, including about 250,000 acres in Minnesota. 

Farmers hurt by dicamba drift are wondering if they're going to see any compensation for their losses. A majority of Minnesota soybean fields are insured through the U.S. agriculture department's crop insurance program. But the federal insurance package will not cover dicamba damage.

For most farmers, it may take some neighbor-to-neighbor negotiations to settle things. Peterson said because it could be difficult to prove definitively that dicamba caused his yield reduction, he's just going to take the loss.

Plus, he doesn't want to upset the good relations he has with the neighbor who sprayed the chemical.

"We've been friends forever and we're going to continue to be that way," said Peterson. "I mean, he feels bad. It's not anything he had intended to happen."