Initial screening confirms multiple herbicide-resistant kochia (Bassia scoparia) in South Dakota

Kochia [Bassia scoparia (L.) A.J. Scott] is a pervasive weed across the North Great Plains and herbicide-resistant biotypes are ubiquitous. Greenhouse experiments were conducted to determine the susceptibility of South Dakota kochia to labeled rates of common herbicides. The collected kochia responded similarly to the susceptible standard population after treatment with atrazine, bromoxynil, lactofen, and glufosinate. All kochia exhibited low susceptibility to glyphosate and imazamox. One kochia population exhibited substantially low susceptibility to saflufenacil. Differential susceptibility to dicamba and fluroxypyr among the tested kochia populations was observed as well. The result of this screening suggests that putative multiple herbicide resistant kochia are likely present in South Dakota.