Ventenata is a weed that has spread across much of the West.

A herbicide coming to market will help control the invasive grass ventenata that has spread across parts of the West, a researcher says.

Ventenata is a tufted annual grass that germinates at moderate to high temperatures. It becomes established in disturbed areas and is highly invasive in bluegrass, alfalfa, winter wheat, pasture, range and Conservation Reserve Program sites.

Livestock won't eat ventenata, so its spread into grazing land causes loss of forage, according to Washington State University.

It is widespread and getting worse, said Steve Van Vleet, WSU Extension educator for Whitman County.

Farmers and ranchers "are desperate for a solution. It is taking over," Van Vleet said.

"It seems like a weaker plant," he said.  Because it's wispy, some farmers assume that "Oh, this wouldn't be hard to get control of," Van Vleet said. "It actually causes damage to harvesting equipment."

The new product, from Bayer, formerly known as Esplanade, will now be known as Rejuvra for rangeland.

"It's the first chemical that I've seen developed that I could almost do a happy dance for," Van Vleet said. "It's providing very good control; it's not causing damage to a lot of our other perennial forbs and perennial grasses that are key, especially within the rangeland sites and grazing lands."

The product has provided 90% control or better, said Van Vleet, who has tested it.

Other control chemicals have been available, but in groups of chemistries to which many plants have developed resistance, Van Vleet said. This is a different herbicide group, he said.

Those chemicals also only provide up to two years of control, he said. The new chemical provides four or five years of control. 

Such long-term control helps eliminate the seed bank in an area, Van Vleet said.

Resistance is always a concern, but Bayer is considering additives of other chemistries with different modes of action for short-term control, reducing the risk, Van Vleet said.

The new product is likely to be used widely, including by the U.S. Forest Service and fish and game departments, Van Vleet said.

Van Vleet's research provided information to Bayer. He said he does not have any financial interest in the product.

Van Vleet plans to resume ventenata field days when possible.

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