Yellow nutsedge has become a difficult to control weed in several regions of Switzerland for the last years. It is easily spread by several means of dispersal. It propagates especially well in row crops and crops of limited competitiveness such as vegetables. Yellow nutsedge causes considerable yield losses. The control is highly challenging. In heavily infested fields the extinction or at least the reduction to a steadily low infestation level of yellow nutsedge will take years. Therefore, prevention is better than cure!