ST. PAUL – Crop scientists at the University of Minnesota and officials at the Minnesota Department of Agriculture (MDA) urge farmers to check fields for Palmer amaranth, an aggressive weed that can put corn and soybean crops at risk. A plant detected in a native seed planting plot on a Yellow Medicine County farm was confirmed Thursday to be Palmer amaranth. This is the first confirmation of the weed in the state.

The MDA asks possible infestations to be reported by contacting the MDA’s Arrest the Pest line by phone at 1-888-545-6684 or by email at arrest.the.pest@state.mn.us. Landowners are encouraged to email photos of suspected infestations for identification.

“We encourage landowners to scout fields now before harvest for Palmer amaranth and report any possible infestations to the Minnesota Department of Agriculture,” said Geir Friisoe, MDA’s Director of Plant Protection. “The quicker we’re able to identify and start managing this weed, the better our chances will be to minimize the impact to our ag industry.”

Palmer amaranth can grow 2 to 3 inches a day, typically reaching 6 to 8 feet, or more, in height. Left uncontrolled, a single female Palmer amaranth plant typically produces 100,000 to 500,000 seeds. It is resistant to multiple herbicides.

It has been found in 28 other states, including Iowa, South Dakota and Wisconsin.

“Palmer amaranth infestations have caused substantial yield losses and greatly increased weed management costs in cotton, soybeans and corn in the southern states,” said Extension agronomist and crops leader Jeff Gunsolus. “This is a disconcerting, though not completely unexpected, discovery in Minnesota. We have been discussing proper identification procedures with crop consultants during our Institute for Ag Professionals educational programs over the last three or more years.”

Extension and MDA officials commend the grower and crop consultant who quickly contacted Extension after discovering a suspected Palmer amaranth plant. The weed is on MDA’s prohibited-eradicated noxious weed list, requiring all above- and below-ground parts of the plant be destroyed. Transportation, propagation or sale of the plants is prohibited.

MDA and Extension continue coordinating action steps to address the weed.

The MDA is investigating how the weed may have been introduced to the state.

In August, an Extension blog updated steps for both prevention and management at z.umn.edu/palamthbknd.

Further information is available at z.umn.edu/MDAPalmerAmaranth.