NDSU Extension warns of noxious weed

Across the Midwest, farmers and ranchers are finding a specific noxious weed in their fields instead of grass, soybeans or corn. This invasive weed, Palmer amaranth, is spreading throughout the nation and causing major problems for the agriculture industry.


Frank Turner
acrnews@countrymedia.net

NDSU Extension is combating the Palmer amaranth outbreak by raising awareness of the weed’s effect on people’s livelihoods. Local NDSU Extension Agent Hannah Nordby said that she has seen the effects of the weed firsthand in other states.  

“It is just a dominant species that comes and takes over,” said Nordby, “It’s a very resilient weed, and once it takes off, it spreads like wildfire.” 

The weed is so prolific that it crowds out native species and even crops. According to an NDSU Extension press release, one Palmer amaranth plant can grow up 3 inches in a day with favorable growing conditions. 

“With any invasive species, they are just going to come in and crowd everything out. Whether you can’t grow native grass or crops, it’s going to have an economic impact.” 

NDSU Extension Cropping Systems Specialist Ryan Buetow said that Palmer Amaranth originated in the desert regions of the southwest U.S. and northern Mexico. Thankfully, Palmer amaranth has yet to make its way to Adams County, however last year the invasive species was found for the first time in the eastern portion of North Dakota. 

Buetow warned that the economic impacts of the plant have been catastrophic in other locations across the nation.  

 “While hearing someone talk about palmer may sound exaggerated, the cost of this weed is huge,” he explained, “Palmer has been shown to reduce yield up to 91% in corn and 79% in soybean. It can emerge at any point in the growing season. The only proper way to manage this weed is a zero tolerance policy. Scouting and knowing how to identify it is something that every farmer should be thinking about.” 

Although it’s not in our county, Nordby said that Palmer amaranth seed can easily spread. Shockingly, one plant of Palmer amaranth can produce over 1 million seeds. Nordby warned that the tiny seeds can be accidentally spread through contaminated equipment, animal feed, seed, and even hay.  

“You have to be careful when buying equipment from other states,” she said. “It’s very difficult to get the invasive species seeds out of equipment once contaminated during the harvesting process. People can easily spread the noxious weed without even realizing.”  

In addition to being easily spread, the noxious weed is also adaptable to new conditions. Over time, the invasive species has developed a resistance to almost every group of herbicide used in crop production 

Although the plant is tough, it’s not invincible. The NDSU Extension press release states that herbicides are most effective when the plant is smaller than 4 inches, however once the weed has grown, the most effective way to handle the weed is by hand picking the plant. 

 “Landowners should scout fields starting in late spring through summer and fall, especially before harvest,” said Nordby. 

Identification is key when dealing with the noxious weed. Palmer amaranth is part of the pigweed family and therefore can be easily confused with Redroot pigweed. In comparison to pigweed, Palmer amaranth has a spiny seed head, spiny bracts, and a smooth stem.

According to Buetow, the Palmer amaranth is a dioecious plant, meaning that there are male and female plants in the same species.  

One palmer plant could look different from another palmer plant. Something that all palmer plants should have in common is a lack of hairs on the plant. If you look closely at redroot pigweed you will find hairs on the plant,” he explained.  

If a person thinks that they have found Palmer amaranth in the southwest region of North Dakota, Buetow suggested taking a picture of the suspected plant and sending it to the closest NDSU Extension county agent. If identified as Palmer amaranth, the ND Department of Agriculture would sample the plant and genetically confirm its presence. 

Nordby also suggested flagging or marking the location of the suggested plant.  

“Leave the plant in place to not spread seed,” she said, “It is also easier to identify if it hasn’t been pulled.” 

Nordby said that people are welcome to contact the NDSU Extension Office at 701-567-2735 for more information or to report a citing. People are also welcome to contact the Adams County and Hettinger County Weed Officer Tim Milliren at 701-853-2942 or 701-928-1216 




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