Effect of cinmethylin against Alopecurus myosuroides Huds. in winter cereals

Cinmethylin is a potential new pre-emergence herbicide in Europe inhibiting the fatty acid thioesterases in the plastid against Alopecurus myosuroides and other grass-weeds in winter cereals and oil-seed rape. Five field experiments were conducted in Southwestern Germany from 2018 until 2020 to assess the control efficacy of cinmethylin and other common pre-emergence herbicides alone and combined with post-emergence herbicides against A. myosuroides and yield response of winter wheat and winter triticale. In four experiments, the effect of early and late sowing of winter cereals was included as the second factor in the experiment to investigate if late sowing can reduce A. myosuroides density weed control efficacy. All fields were heavily infested with A. myosuroides with average densities of 110-730 plants/m2. Late sowing reduced densities in three out of four experiments. Herbicides controlled 42-100% of the A. myosuroides plants. However, none of the treatments was consistently better than the other treatments over all experiments. In three out of 5 experiments, grain yields were significantly increased by the herbicide treatments. The results demonstrate that cinmethylin increases the options for controlling A. myosuroides in winter cereals. However, it needs to be combined with other control tactics.