Herbicide Resistant Weeds

Lack of cross-resistance of imazaquin-resistant Xanthium strumarium acetolactate synthase to flumetsulam and chlorimuron.

Schmitzer, P. R., R. J. Eilers, and C. Cseke. 1993. Lack of cross-resistance of imazaquin-resistant Xanthium strumarium acetolactate synthase to flumetsulam and chlorimuron. Plant Physiology. 103: 281-283.

Acetolactate synthase (ALS) was isolated from a field population of cocklebur (X. strumarium) in Bolivar County, Mississippi, that had developed resistance to the herbicide Scepter (imazaquin) following 3 consecutive years of application. The herbicide concn required to produce 50% inhibition of the enzyme activity was >300-fold greater for resistant ALS than for the wild-type X. strumarium enzyme. Tests with flumetsulam and chlorimuron showed that the resistant ALS was not cross-resistant to these other 2 classes of ALS inhibitors.