Wyoming Researchers Probe for Herbicide Resistance Solution

Kochia focus of five-year study.

Published on: Nov 21, 2013

University of Wyoming scientists are focusing on kochia in a five-year probe to find a solution to find a solution to weed resistance in herbicides.

Department of Plant Sciences associate professor Andrew Kniss has a National Institute of Food and Agriculture grant to analyze methods of weed control other than chemical herbicides.

Experimental kochia populations will be seeded in fields without major infestations, and all sites will be sprinkler irrigated.

The weeds will have herbicide-resistant and susceptible strains, and exposed to various treatments including crop rotation and tillage. Soil samples collected each fall will be used to record management pesticide data relative to the kochia.

Kochia is being used as a weed target for a new herbicide resistance study in Wyoming.
Kochia is being used as a weed target for a new herbicide resistance study in Wyoming.

Sites at research stations in Powell, Wyo.; Scottsbluff, Neb., and Huntley, Mont., will be used in the study to represent three different regions significantly affected by the kochia. Economic and biological effects of kochia will be evaluated using statistical analysis on data collected in the field. Statistical modeling is the most commonly used tool because field study data is lacking in part because of expense, says Kniss.

The economic impact of factors like fuel, labor, fertilizer and crop prices will determined in the study.

"Diverse crop rotations and tillage are commonly recommended for management of herbicide-resistant weeds, but there is still not that much field-based information on how successful these approaches will be," he says. "Since tillage and crop rotation are still quite common in our region, we thought that this is a great opportunity to see how these practices actually influence development of herbicide-resistant weed populations."

Kochia is one of the most problematic weeds in Wyoming, as well as many other western states.

"It infests both dryland and irrigated cropping systems and is particularly troublesome in sugar beet production," Kniss observes. "It has evolved resistance to many commonly used herbicides, including dicamba, atrazine and glyphosate. So any information we learn about managing this species could have a big economic impact."