A strategy of chemical control of Apera spica-venti L. resistant to sulfonylureas traced on the molecular level

Abstract

Three populations of silky bent grass (Apera spica-venti L.) were tested – one that is susceptible and two that are resistant to sulfonylureas. This study assessed the efficacy of control by different herbicides in a pot experiment and estimated the molecular status of resistance to sulfonylureas in analysed populations and its effect on the efficacy of different chemical treatments. The three most effective herbicide rotation schemes were: 1) chlorsulfuron + isoproturon, ethametsulfuron + metazachlor + quinmerac, chlorsulfuron + isoproturon; 2) prosulfocarb + diflufenican, ethametsulfuron + quizalofop-p-ethyl, prosulfocarb + diflufenican; 3) diflufenican + flufenacet, quizalofop-p-ethyl, diflufenican + flufenacet. In most cases it was more difficult to destroy 100% of the resistant population from Modgarby where the majority of plants had no mutation in the als gene. In the resistant population from Babin there were significantly more individuals with mutation in the als gene, therefore exhibiting target-site resistance.

Keywords

• ALS inhibitors
• non-target-site resistance
• silky bent grass
• target-site resistance
• weed control