The Minnesota Department of Agriculture (MDA), in collaboration with University of Minnesota Extension, has confirmed a new Palmer amaranth infestation in a Redwood County soybean field.

In mid-September, a farmer noticed several weeds he suspected as Palmer amaranth – a highly invasive weed. Genetic testing of four plants found in the field confirmed they were Palmer amaranth.

MDA staff scouted fields within a five mile radius of the field and have not found any other plants. The MDA is investigating where the Palmer amaranth seed came from.

“Given the limited number of plants, we are optimistic this infestation is contained to a small area,” said Mark Abrahamson, MDA’s director of plant protection. “Given its potential harm to our ag industry, we will search for a source of the plant and work with the farmer to monitor the area next year. We have successfully eradicated the plant in other parts of the state and will work to achieve the same results in Redwood County.”

Palmer amaranth was first discovered in Minnesota in 2016 in Lyon and Yellow Medicine counties. 

Palmer amaranth can grow two to three inches a day, typically reaching six to eight 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, can cause substantial yield losses and greatly increase weed management costs. Because of the impacts it can have to Minnesota’s crops, Palmer amaranth is listed as a prohibited weed seed. This means no Palmer amaranth seed is allowed in any seed offered for sale in the state.

It is also on Minnesota’s prohibited noxious weed eradicate list.

All above and below ground parts of the plant must be destroyed.

No transportation, propagation, or sale of this plant is allowed.

Learn more at www.mda.state.mn.us.

Photo courtesy of the Minnesota Department of Agriculture