Farmers and agronomists encouraged to scout fields for invasive weed

A Palmer amaranth plant found in a Goodhue County corn field was not killed by a recent herbicide application. Photo courtesy Minnesota Department of Agriculture.

The Minnesota Department of Agriculture (MDA) has positively identified the invasive weed Palmer amaranth in Goodhue County.

After a crop consultant reported a suspected plant to the MDA, staff conducted a site visit and found the weed in two corn fields managed by one farmer. The MDA scouted fields surrounding the documented infestations and did not find any additional Palmer plants. It is unknown at this time how Palmer amaranth got into the two fields; however, the MDA is continuing to investigate potential sources.

An herbicide application stunted but did not kill the plants. A crew hand-pulled weeds in the two fields to eliminate any chance of seed production. The MDA will continue to work with the farmer, crop consultants, U of M Extension, and the County Agricultural Inspector to manage these infestations.

“This is a good example of the limits of herbicide on Palmer amaranth,” said Denise Thiede, MDA’s Seed Unit Supervisor. “If plants are allowed to reach a certain size, an herbicide application may not control them. That’s why we’re counting on farmers and crop consultants to report suspected plants. They are our best line of defense against Palmer amaranth.”

In Minnesota, Palmer amaranth is listed as a noxious weed and a prohibited weed seed. This means no Palmer amaranth is allowed in any seed offered for sale in Minnesota.

Palmer amaranth is resistant to multiple herbicides, can cause substantial yield losses, and greatly increase weed management costs in soybeans and corn.

The MDA is asking farmers and agronomists to take photos of suspicious plants, pull them out, and save them in plastic bags for genetic testing if needed. Report the find to the Minnesota Department of Agriculture’s Arrest the Pest line at 1-888-545-6684 or arrest.the.pest@state.mn.us.

MDA’s full press release on this topic can be found online, here. Find more information about Palmer amaranth on the MDA website, here.

Palmer amaranth has long flowering spikes that are spiny. The plant can produce hundreds of thousands of seeds in a short time frame. Seeds mature within 10-12 days after pollination. Photo: MDA.

The Minnesota Department of Agriculture (MDA) has positively identified the invasive weed Palmer amaranth in Polk County. The confirmation came after the MDA inspected a field being used for the disposal of agricultural screenings.

The MDA collected a sample of the screenings material and determined by genetic testing that it was contaminated with Palmer amaranth seed. The field was scouted, and MDA staff found several dead Palmer amaranth plants on the field’s edge remaining from last year, suggesting the plants had grown and matured.

The landowner is working with the department to eradicate any of the weeds moving forward. At this time, the MDA believes the issue is isolated to only one field. The field and the surrounding area will be a priority for MDA field scouting this summer.

Since it was first discovered in the state in 2016, Palmer amaranth has been found in ten Minnesota counties, including Polk County. Most of the sites have been successfully eradicated and the remaining are being closely monitored.

In Minnesota, Palmer amaranth is listed as a noxious weed and a prohibited weed seed. This means no Palmer amaranth is allowed in any seed offered for sale in Minnesota.

Palmer amaranth is resistant to multiple herbicides, can cause substantial yield losses, and greatly increase weed management costs in soybeans and corn.

MDA’s full press release on this topic can be found online, here. Find more information about Palmer amaranth on the MDA’s website, here.

Tag: prohibited weed seed

Palmer Amaranth Found in Goodhue County

Farmers and agronomists encouraged to scout fields for invasive weed

Palmer Amaranth Found in Polk County