Situation and development of herbicide resistance in Black-grass (<i>Alopecurus myosuroides</i>) in Bavaria

Abstract

Black-grass (Alopecurus myosuroides) is one of the most important grass weeds in Bavaria. Chemical weed control with high efficacy is very important in crops like winter cereals, oilseed rape and maize. Crop rotations with more winter cereals, reduced soil cultivation and e.g. contract harvesting enhanced distribution of blackgrass in all arable farming regions of Bavaria. Effects of herbicide resistance were observed since the last 20 years. The black-grass herbicide resistance is well observed by the official plant protection service of Bavaria. A wide experience of resistance tests shows the development of resistant black-grass. At the beginning of the test period in 2004 resistance to ACCase-Inhibitors was most important. Currently a selection pressure for resistance to ALS-Inhibitors is the greatest problem. During the course of the test program multiple resistance and multiple target-site resistance occurs increasingly.