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Weed Science Researchers Featured in The Forum

Dr. Richard Zollinger, NDSU Extension Service weed specialist and research specialists Aaron Carlson and Devin Wirth discussed efforts to control herbicide resistant weeds during the 2015 Wild World of Weeds workshop. They were featured in this article published in The Forum of Fargo-Moorhead January 29. The Wild World of Weeds workshop is planned annually by NDSU Extension and Plant Sciences employees.
Weed Science Researchers Featured in The Forum

Rich Zollinger (right) and Devin Wirth talk weeds with participants at Wild World of Weeds Workshop. (Trevor Peterson/The Forum)

The article was written by Tracy Frank and published by The Forum on January 29, 2015. It is reprinted here with permission. Contact Tracy at  or (701) 241-5526.

FARGO - North Dakota State University researchers are trying to get to the root of the herbicide-resistant weed problem in the state.

The biggest offenders, according to Rich Zollinger, NDSU Extension Service weed specialist, are waterhemp and kochia. Both, he said, are showing resistance to glyphosate, the active ingredient in Roundup, making the weeds tough to kill.

“Because we have had no new herbicides the last 10 to 15 years, we’re overusing some of the ones that really work well,” he said. “Because we overuse, then weed resistance comes in, so weed resistance is probably one of the most concerning topics that growers face.”

While glyphosate-resistant kochia is a big problem statewide, Zollinger said gyphosate-resistant waterhemp is one of the most serious weed problems in eastern North Dakota.

More than 300 people attended the Wild World of Weeds workshop this month in Fargo to learn about NDSU’s latest research in crops, weed control programs and herbicides.

Bob Joerger, a sales representative for AgraCity, which sells crop inputs to growers, attended the workshop and said it’s important to stay on top of the changes and the latest research in the weed industry.

“We’re all working together to help the grower, so I find it’s pretty important to be in places where you’re continually learning,” he said.With 14 faculty professors, researchers and scientists, Zollinger said NDSU has one of the largest weed science groups in the nation.


NDSU research specialist Aaron Carlson talked about waterhemp control in sugar beet crop rotation.

“Waterhemp is a problem sugar beet growers have been facing more and more the last few years,” he said.

It’s especially problematic, he said, for farmers in the southern parts of the Red River Valley and central Minnesota.

“It kind of broke loose this past season,” he said. “It was a late spring, so once summer finally did come around, the temperatures and conditions were just right for it. It really grew rapidly.”

It’s an issue, he said, that has been developing over the past five or six years and is starting to reach a threshold in certain areas.

“Sugar beets rely heavily on glyphosate. It’s the best weed-control herbicide that we have,” he said. “That is the primary concern with waterhemp. The populations that are developing resistance, they’re tough to control.”

What sugar beet farmers can do, he said, is use a pre-emergent herbicide or a soil residual herbicide like post-emergence and control the weed throughout the other crops in the rotation.

Matt Chaput, an agronomist and cattle rancher near Walhalla and Langdon, N.D., said it can be a scary situation when the herbicides farmers are used to using stop working.

“If you can’t control the weeds, the weeds are competing against the crop and you’re losing bushels and you’re losing money,” he said. “If it’s not working you’re wasting that money and you’re losing yield. There’s a lot of money put into that crop. It’s a high-dollar game.”


Researchers also talked about Palmer amaranth, a glyphosate-resistant weed that adapts quickly, competes aggressively with crops, and can produce anywhere from 100,000 to 500,000 seeds.

“When a plant like that moves into North Dakota and there’s so much glyphosate being sprayed out there, it’s very hard to get rid of,” said Devin Wirth, NDSU research specialist.

So far, Zollinger said, North Dakota and Minnesota are the only two states that have not yet documented the weed’s presence.

“Our objective is to keep it out of North Dakota and to do that we need good identification,” he said.

Workshop participants spent the afternoon learning how to identify 20 to 25 weed species, including waterhemp, and Palmer amaranth.

“We are on an identification blitz,” Zollinger said. “If they can identify it early, we can take the necessary actions.”

If it is found, a group of people including agronomists, Extension specialists and consultants participating in an early-detection program will move in to try to eradicate the weed, he said.

The seed is very light, so it moves with water and can be carried by custom combiners, but Zollinger said the most likely way it will enter the state is by way of a bird’s digestive tract.

“They’re highly nutritious seeds,” he said. “Birds are going to eat the seed, and with the migration of birds, I think the birds may be a way that we might get it.”

For more information about NDSU Weed Science program, visit

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