ST. PAUL — The Minnesota Department of Agriculture (MDA) has confirmed a new Palmer amaranth infestation in a conservation planting – this time in Todd County.
The MDA is investigating where the Palmer amaranth seed came from; however, officials believe the weed is limited to specific planting sites.
“There are several factors working in our favor that lead us to believe we can find, control, and eliminate this new Palmer amaranth find,” said Geir Friisoe, MDA’s Director of Plant Protection. “The Todd County planting was seeded in late June; and with our cold overnight temperatures earlier this week, it’s unlikely there is any viable seed on the plants. Also, thanks to local officials who were on the lookout for Palmer and notified us immediately, we were able to quickly find and identify the Palmer, and make a plan for eradication.”
Palmer amaranth was first confirmed in Minnesota in 2016 in Lyon and Yellow Medicine counties. Because of swift action there to control its spread, a small number of plants were found this year at the 2016 sites.
With continued herbicide treatment next year, Friisoe stated he is optimistic MDA can completely eradicate the weed infestations in Lyon and Yellow Medicine counties, and he is confident the same can happen in Todd County.
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, and can cause substantial yield losses and greatly increase weed management costs in soybeans and corn.
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. Also, no transportation, propagation, or sale of this plant is allowed.
The invasive weed is native to the southwestern United States and northwestern Mexico. It has been found in 28 other states, including Iowa, South Dakota and Wisconsin.