Characterisation of iodo- plus mesosulfuron resistance in an Alopecurus myosuroides Huds. Population from the Czech Republic

Abstract

Alopecurus myosuroides Huds. (black-grass) is one of the most challenging annual grass weeds in cereal-based rotation fields in Western Europe, with increasing densities of this weedy species (Délye et al. 2011, Rosenhauer andPetersen 2015). Some factors responsible for this intensification might be due to rotations with high proportions of winter cereals and reduced tillage (Lutman et al. 2013, Messelhäuser et al. 2021. Black-grass is a very competitive and economically important weed and might cause almost 15-20% (at densities of 100 plants/m 2 ) yield losses in winter wheat production (Gerhards et al. 2016, Messelhäuser et al. 2021. The evolution of herbicide resistance to five herbicide mode of action in A. myosuroides has risked their management in Europe where acetolactate synthase (ALS)-inhibitors (HRAC Group 2), acetyl-CoA carboxylase (ACCase)-inhibitors (HRAC Group 1) and PSII-inhibitors (HRAC Group 5) are mainly used, to manage this species (Moss et al. 2007, Cummins et al. 2013, Klauk and Petersen 2023.Since their commercialisation, ALS-inhibiting herbicides have been widely used for weed management due to their broad-spectrum weed control efficiencies (Mazur and Falco 1989). Some commonly used ALS-inhibiting herbicides against A. myosuroides include pyroxsulam, mesosulfuron-methyl, mesosulfuron plus iodosulfuron, etc. These herbicides