palmer amaranth

Mississippi State University crop weed specialist Dr. Jason Bond talks to a producer about Palmer amaranth at a workshop on Tuesday, Nov. 5.

SIDNEY — The MonDak is already dealing with a number of herbicide-resistant weeds, from kochia to wild oats and Russian thistle. It will likely soon add another to the list — Palmer amaranth.

To help producers prepare, Richland County Extension, along with the Eastern Agricultural Research Center and the USDA-ARS unit, all in Sidney, Montana, helped sponsor a get-to-know the enemy workshop, in hopes of slowing down the invasion of what many have described as a super weed.

Montana State University cropland weed specialist and research professor Dr. Tim Seipel said it is unlikely that Palmer amaranth will be kept from entering Montana, but that knowledgeable producers working together can help slow its spread.

This means knowing what the weed looks like, and doing a better job of scouting fields to look for the weed — preferably when it is still small and easier to control.

In the event growers find the weed, Seipel wants producers to contact their extension agent, to ensure proper identification and steps are immediately taken to manage the issue.

Among his recommendations, growers should make sure to use full rates of pre-emergence herbicides. To be effective, the weed needs to be less than 3 inches in height, otherwise it can just outgrow the herbicide. A stepwise application of post-emergence herbicide with residuals is also recommended, to help deal with the weed’s prolonged emergence pattern.

Producers who might be thinking the MonDak’s saline soils or its extra cold winters could help slow down this desert southwest native are probably just wishful thinking, visiting Mississippi State University Weed Scientist Dr. Jason Bond said.

“It acclimates to the geography it’s growing in,” he said.

The plant in South Carolina has more leaf area than the stemmy version that has adapted to Texas, he said, changes that happened over the course of just a few generations.

“The seed production is so great, you can get those evolutionary characteristics pretty quick,” Bond told the Williston Herald after the presentation.

Each weed that is missed, meanwhile, is laying down a huge seed bank all at once. One seed head is full of up to 500,000 seeds, Seipel said.

The seeds are also teeny-tiny, Bond said, and easily get caught on equipment, train cars, and even muddy boots. They are hard to spot in a batch of other tiny seeds, as well. Millet has been a particular problem.

“A handful of (Palmer amaranth seed) is just full of static electricity,” Bond added. This makes them prone to blowing off in the wind, or even just jumping apart as they brush up against each other.

NDSU weed scientist Dr. Brian Jenks, meanwhile, said producers need to ask questions about the origin of seeds they are buying, particularly if they are small seeds like millet.

“I know we have some seed salesmen that farmers won’t buy from any more, because they weren’t up front about Palmer being in the seed,” he said.

North Dakota’s state seed department is inspecting seed supplies for Palmer, but they are difficult to detect because the seed is so small.

“I’m hoping, and I do think that we are making all farmers and crop consultants and seed salesmen much more aware (of this),” Jenks added. “In almost every area where Palmer was found, out was because the farmers were aware that the plant looked different or an agronomist saw it. So our educational processes have been effective. People are aware, and they are concerned about it.”

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