Palmer amaranth weed in a field.

SAINT PAUL, Minn. – Palmer amaranth continues to try to make its way into Minnesota. This time, it showed up in a soybean field in Jackson county.

“It sounds worse than it is, for what we know right now,” said Tony Cortilet, head of the Noxious Weed Program at the Minnesota Department of Agriculture, during a recent phone interview. “Yes, Jackson County is within the borders, it was one plant that we were alerted to.”

A farmer found the plant a little over a month ago while he was hand weeding his soybean field. He thought it looked strange, so he pulled it, bagged it and sent it off to the University of Minnesota Extension.

The Extension sent the plant to the diagnostics lab at the University of Illinois for genetic testing. It was there the plant was confirmed to be Palmer amaranth.

“The good news is that individual plant was pulled,” said Cortilet. “It was a female plant and it had not gone to seed.”

Palmer is an annual. For it to be a problem in the next growing season, it must develop and disperse seeds. This farmer caught the plant before it had that chance and got it out of the field.

“We did send our Palmer Eradication Coordinator out there the next day to meet with the farmer,” he said. “He started at where the plant was found and then did a five-mile radius search of all the soybean and corn fields and we did not find any other Palmer plants.”

It is not yet clear how the plant made its way into Jackson county and the MDA is continuing to investigate.

There are several factors and possibilities as to how Palmer seed might have made it to the Minnesota field. The weed is present in over 50 counties in Iowa and Jackson County is right on the border.

The MDA has a very active program working to keep Palmer amaranth out of the state. When it is found, the team goes to the site to eradicate the weed.

Prior to this year, Palmer had not been found on any cropping acres.

“We have been dealing with it in conservation acres in four other counties up until this year when the Jackson and then Redwood County find occurred,” he said. “We have been able to eradicate it on CRP acreages in a Todd, Lyon, Yellow Medicine and Douglas counties.”

In was in 2016 that Palmer amaranth was discovered in Lyon and Yellow Medicine counties and in Todd and Douglas counites in 2017, coming in contaminated seed for conservation planting. The MDA eradication team started working immediately to remove the plants and prevent seeds from spreading and germinating the next year.

The plants and surrounding soil were burned the first year to destroy the plant and any seed that may have fallen. The next year, 2017, herbicide was used on some of the sites. Any surviving plants were pulled up, bagged and incinerated.

“This year, we found absolutely no Palmer on those sites,” he said. “We did not do any herbicide applications this year. We just did intensive scouting on those sites and we did not find any Palmer growing on those fields.”

The fact that these were CRP acres contributes to the success of the control. At this point, the grass species have established and are able to outcompete Palmer amaranth, preventing it from continuing to be a problem.

It is a different situation for corn and soybean fields. Palmer, like any of the other pigweed species, will have no problem establishing and becoming a problem for growers.

“We want to make sure that when we get these finds, we get out there right away to remove the plants,” he said. “The last thing we want is that stuff going through a combine.”

If a grower sees a suspicious weed in their field, they should remove it, bag it and then contact the University Extension or the MDA so it can be tested to determine the exact species.

While the MDA must publish the county where Palmer amaranth has been found in, the exact location and land owner information remains confidential.

“We are not sharing the locations with the general public right now, mostly to protect farmers so that they continue to keep coming forward,” said Cortilet. “Some farmers have been somewhat nervous about even reporting these locations because they're afraid the kind of public disdain, if you will, that might occur from it.”

To keep Palmer amaranth out of the state, it is essential the MDA is alerted to any potential weed in the state. It is important farmers know how to recognize Palmer from other pigweeds and that they take action immediately if they see it.