The Minnesota Department of Agriculture confirmed last Friday a new Palmer amaranth find in Douglas County. The invasive weed has now been detected in four Minnesota counties: Douglas, Lyon, Todd, and Yellow Medicine.

The Douglas County infestation was found through MDA’s investigation into a Palmer amaranth find in Todd County. That investigation is still ongoing as the Department searches for the source of the weed seed.

“It is fortunate that we are finding these infestations early on,” said Geir Friisoe, the MDA’s Director of Plant Protection. “Through early detection, we can develop an effective eradication plan and manage these small, isolated sites before the weed spreads beyond the plantings.”

All of the Minnesota infestations have been found in conservation plantings. None of the weeds have made their way into row crop fields, which could be economically harmful. Palmer amaranth can cause substantial yield losses and greatly increase weed management costs in soybeans and corn.

It is illegal to sell any seed in Minnesota that contains Palmer amaranth. Dealers must test seed lots before putting them on the market. Proper seed labeling laws must also be followed.

“To help curb the spread of this weed, landowners should buy seed mixes from reputable seed dealers,” Friisoe said. “You should ask the dealers to see the blending paperwork and lab certification results.”

The MDA is having success in eradicating the 2016 finds in Lyon and Yellow Medicine counties. A small number of weeds were found this year, a major decline when compared to the initial discoveries last fall.