Resistance patterns of a bur chervil (Anthriscus caucalis M. Bieb.) population with a point mutation within the acetolactate synthase gene in comparison with sensitive bur chervil and further weedy Apiaceae species

Abstract

Weeds of the umbelliferous family (Apiaceae) are gaining importance in several crops and regions and are often difficult to control chemically. For example, the occurrence of bur chervil (Anthriscus caucalis M. Bieb.) is not only increasing as a ruderal plant, but is also establishing as an arable weed in winter crops. There, it is often not sufficiently controlled by standard measures and beyond that frequently confused with other weedy umbellifers. In addition, the first A. caucalis populations with resistance to inhibitors of the acetolactate synthase (ALS) have been described. For this reason, we sequenced the ALS gene of a sensitive and a resistant A. caucalis population and found a mutation at position Pro197. This population was compared with a sensitive one, as well as other umbellifers such as hedge parsley (Torilis arvensis (Huds.) Link), wild carrot (Daucus carota L.) and hemlock (Conium maculatum L.) in a greenhouse trial with 14 herbicides. There were clear differences between the treatments of sensitive and resistant A. caucalis and the other umbellifers. The sensitive A. caucalis population was effectively controlled by the ALS inhibitors thifensulfuron, tribenuron and metsulfuron, but not by florasulam. Of these herbicides, only metsulfuron had a partial efficacy on the resistant population with 71.8% freshwater reduction. Notably, the efficacy profiles of ALS inhibitors differed significantly between species, while several synthetic auxins and chlortoluron effectively controlled most populations tested. Finally, the correct identification of the umbellifer species, as well as the resistance status, is necessary to carry out targeted chemical control.

Keywords

• acetolactate synthase
• apiaceae
• bur chervil
• herbicide resistance