Multiple resistance to acetolactate synthase (ALS)- and acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides in black-grass (Alopecurus myosuroides Huds.) populations from Poland

Alopecurus myosuroides seeds were sampled from 32 winter wheat fields from 2010 to 2014. Resistance to herbicides was detected in 17 A. myosuroides populations. In addition to single resistance to herbicides, cross-resistance and multiple resistance to acetolactate synthase (ALS)- and acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides were found. Application of sulfometuron and imazapyr was unable to control some of the resistant biotypes in this study. This result implies that resistance in these populations is due to a target site mechanism. The A. myosuroides biotypes resistant to ACCase-inhibiting herbicides varied in their responses to derivatives of aryloxy-phenoxy-propionic acid (FOPs), cyclohexanediones (DIMs) and phenylpyrazolines (DENs). Resistant biotypes of A. myosuroides that could not be controlled with fenoxaprop-P-ethyl (FOP) and pinoxaden (DEN) were controlled with clethodim (DIM).