It's official: Palmer amaranth in N.D.

Tom Peters worked to delay what he knew was inevitable: the arrival of Palmer amaranth in North Dakota. But now the dangerous weed officially has been identified in the state, and so Peters is urging agriculturalists to keep fighting the good fig...

UNL associate professor Greg Kruger works with a graduate student at one of the wind tunnels in the Pesticide Application Technology (PAT) laboratory on the West Central Research and Extension Center campus in North Platte, Neb., on Tuesday, August 15, 2017. Nick Nelson / Forum News Service
Tom Peters, NDSU assistant professor and extension agronomist, examines a Palmer amaranth plant near Holdrege, Neb., on Wednesday, Aug. 16, 2017. For reference, Peters stands six-foot-three-inches and the Palmer amaranth plant towered over him. Nick Nelson/Agweek

Tom Peters worked to delay what he knew was inevitable: the arrival of Palmer amaranth in North Dakota. But now the dangerous weed officially has been identified in the state, and so Peters is urging agriculturalists to keep fighting the good fight to minimize Palmer's impact.

"It's really going to take a combined, all-out effort," said Peters, a North Dakota State University agronomist and assistant professor who's played a key role in NDSU's efforts to educate farmers and others in the state about the weed.

It was indeed Palmer amaranth plants found in a soybean field in McIntosh County in south-central North Dakota, the North Dakota Department of Agriculture and NDSU Extension announced in separate statements on Aug. 28. That followed DNA testing at the University of Illinois, which confirmed that the plants were Palmer amaranth.

A preliminary announcement that Palmer had been found in the state - in the form of a tweet from an agronomist who had seen the plants - was based on molecular identification by the University of Illinois, not DNA testing. Palmer can be mistaken easily for pigweed or waterhemp, so NDSU and state ag officials wanted the higher level of certainty provided by DNA testing.

More than one Palmer amaranth plant was found in the field, but "there wasn't an outbreak or a large number of them, either," Peters said.


The weeds have all been pulled, he said.

The farmer is not being named. Identifying him only by county, presumably sparing him from attention from the news media and general public, will encourage other farmers who spot unknown and potentially dangerous weeds to contact experts, Peters said.

The farmer spotted the weeds when scouting his fields, then pulled them and showed them to an agronomist, who contacted NDSU weed specialists, according to the NDSU announcement.

Peters praised the farmer's diligence and willingness to seek outside help and said the group effort reflects what's needed to fight Palmer amaranth.

"I'm really encouraged to see that the process worked so well," Peters said.

The Twitter post on Aug. 16 identified North Dakota's LaMoure County as the location in which Palmer had been found. But Jesse Moch, the agronomist who sent the tweet, told Agweek that McIntosh is the correct location.

The joint effort in spotting and then identifying the plants shows the value of farmers and others working together to control Palmer, Moch said.

The North Dakota Department of Agriculture says the public should work with "local weed officers, extension agents and other experts to identify and report suspect plants."


Doug Goehring, state ag commissioner, said in a written statement that "early detection is the key to effectively eradicate or manage this weed. We are thankful it was found and encourage farmers and the public to learn to identify Palmer amaranth in order to react quickly to control the weed."

To report a suspect plant, contact the North Dakota Department of Agriculture at 701-328-2250 or NDSU Extension at 701-231-8157 or 701-857-7677

Why it's so bad

Palmer amaranth, a huge and longstanding concern in the southeastern United States, already has been identified in Minnesota and South Dakota. It can damage farm equipment and devastate yields. Yield losses of up to 91 percent in corn and 79 percent in soybeans have been reported.

It was voted the the nation's most troublesome weed by the Weed Science Society of America and has a unique combination of characteristics that make it especially dangerous:

• It's a prolific seed producer, with a single plant producing as many as 1 million seeds.

• The seeds are extremely small, making them relatively easy for farmers to spread unintentionally.

• Seeds can lie dormant in the soil for years, waiting to germinate until growing conditions are favorable.


• The seeds are unusually competitive with most crops, including corn and soybeans.

• It can grow as much as 3 inches per day - and the bigger it is, the harder it is to control.

• Because it closely resembles pigweed and waterhemp, especially when small, farmers may misidentify it and take inadequate steps to control it.

Peters said that farmers and other agriculturalists should continue to watch for pigweed and waterhemp, which remain destructive and dangerous weeds.

Palmer amaranth (Photo courtesy University of Minnesota)
Palmer amaranth (Photo courtesy University of Minnesota)

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