Influence of long-term used herbicides on resistance development in Apera spica-venti L. to sulfonylureas

Sulfonylurea herbicides are widely used for grass and broadleaf weed control in winter cereals in Poland developed resistance, especially in Silky bent grass (Apera spica-venti). The aim of the study was to evaluate the possibility of resistance increase after six years used of some herbicide for control of A. spica-venti in winter cereals monoculture. The field experiments were conducted in Agricultural Experimental Station at Winna Gora. During six years the herbicides: chlorsulfuron, sulfosulfuron, iodosulfuron and isoproturon were applied. In fourth, fifth and sixth years A. spica-venti seed from the experiment was collected and used in greenhouse experiment. The obtained results indicated that after six years usage of the herbicides resistance of A. spica-venti to sulfonylurea herbicides were found. Results obtained in field condition were confirmed in greenhouse experiment. Resistance process was found also on untreated plots. It was indicated that resistance is transferred also by pollen.