Invasive weed a serious concern for local farmers

Monroe County Noxious Weed Commissioner Chris Howell stands next to an infestation of Palmer Amaranth weeds in the bottoms off B Road. The weeds can grow up to three inches a day and their characteristic seed stalks can be two feet long. (Alan Dooley photos)

Palmer amaranth is a rapidly growing weed that is emerging in Monroe County and attracting the attention of farmers from the bottoms to the bluffs and inland.

The Republic-Times sat down with Monroe County Noxious Weed Commissioner Chris Howell to discuss the plant itself and the threats it poses to farmers who find it in their fields.

Unlike many invasive species, palmer amaranth is native to the United States, coming from the desert southwest.

University of Illinois Extension authority Robert Bellm said the weed spread across the southern tier of states first and is now moving northward over the last half-century.

“I believe I first saw it in Monroe County in 2005,” he noted.

Bellm and Howell both cited examples of agricultural devastation and huge expenses for farmers in the south, where it has damaged soybean and cotton crops. Bellm emphasized that the impacts of the weed are still in the southern states, but acknowledged there is potential for the same economic consequences here if we don’t do a good job of controlling it.

Howell said some farmers in southern states are having to go to the extraordinary expense of hiring large numbers of trained personnel to meticulously scour fields to dig up and remove the plants by hand.

“And you can’t just cut them and drop them. They have to be bundled and removed physically from the fields. That’s extremely expensive,” Howell added.

Bellm said there are stories of farmers in the south who have lost their farms to the rapidly growing weed.

“They’ve simply gone bankrupt between fighting it and at the same time, getting no crops in return,” he said.

So why don’t farmers just douse this stuff with Roundup and get on with business?  Isn’t that why we have Roundup resistant crops?

In many fields, Roundup simply is not effective against most palmer amaranth because it has developed resistance to the herbicide.  It takes a combination of herbicide – so-called multi-option chemicals, timed correctly and applied properly according to Gateway FS chemical salesperson Dale Burmester, who also carries the title as a certified crop advisor by the American Society of Agronomy.

A pre-emergent chemical cocktail is applied to a field of soybeans as they emerge.  Then 21 days later, Burmester said, a second post-emergent must be applied before any weeds start to appear to compete with the emerging beans.

Burmester acknowledged that the weed is not easy to kill.

“Palmer amaranth can be controlled,” he emphasized.

If the crop plants get a firm hold, they will crowd out the palmer amaranth.

“It does not like competition,” Burmester added.

But he also said the weed itself is fast growing, strong competitor.

“Left on its own, it’ll choke out johnsongrass,” he noted.

Some who have gone under in the south have done so because they established an arbitrary limit on treatment and they gave up when their guess proved ineffective.

“But if you lose a crop – that’s not a good business plan,” he noted.

How has this plant spread?  Is it a climate-related issue?  Both Howell and Bellm emphasized how fertile the plant is, with seed stems that can hold as many as a million pepper-grain-sized seeds. They can be carried in crevices in farm machinery and even in dirt on tires of any equipment that operate in fields.

“Cotton seed is sometimes used in animal feeds, too,” Bellm said.

The tiny palmer amaranth seeds can sometimes become stuck in fibers on the cotton seed and enter cattle digestive tracts, and when their manure is applied to fields, it is a palmer amaranth seed and fertilizer mixture.

The invasion of palmer amaranth is not a major threat to urban or even suburban areas.  Grass tends to crowd it out and prevent seeds from germinating.  It is mainly a threat to farm fields, although it is also often seen in roadside shoulder-ditch areas as well.

Bellm did say he has seen a three-foot-tall example growing from a crack on the edge of a road near Edwardsville.

So why should those who do not farm care about another problem for farmers? Crop productivity and costs directly impact agricultural commodity prices.  This in turn, shows up in grocery stores.

Agriculture groups are raising awareness of palmer amaranth and trying to educate people about its threat.

Numerous websites have good information and pictures of palmer amaranth.  One especially good one is, where you can find an article with color photos. Pictures show how the plant differs from another farm crop weed – waterhemp, which is also a member of the amaranth family.  Leaf shapes and markings, as well as stem lengths (palmer amaranth’s stem, when folded back over the leaf, is longer than the leaf) are clues to identification.

If you suspect you may have palmer amaranth on your property, call Howell at 939-8681, ext. 289.   

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