Implementation of control strategies against yellow nutsedge (Cyperus esculentus L.) into practice

Yellow nutsedge (Cyperus esculentus L.) is one of the most dangerous weeds in agriculture because of its high multiplication potential, its high risk of tuber dispersal with vehicles and machines and because of its limited control options. Yellow nutsedge control must always aim to prevent the formation of new tubers. Our control strategy is adapted to various infestation levels, which we distinguish “initial infestation”, “small infested zone” and “infested field”. In the case of “infested fields” questions arise on adaptation of the rotation or even on abandonment of crops. Our experiences showed that only s-metolachlor had good efficacy in reducing considerably the number of tubers. Less effective herbicides left back a number of surviving plants, themselves forming at least a reduced number of new tubers. The proposed control strategies are currently tested in a nationwide network of pilot fields in Swiss agricultural practice. The tuber numbers counted after the first year of control measures did not change dramatically. We observed a slight increase in tuber numbers in almost a third of the fields. The reduction of tuber numbers in the rest of the fields was lower than expected. Inaccurate estimation of the infestation level is always very likely, because the young shoots visible don’t give a reliable image on the real number of tubers in the ground. For improving the control strategies in regard to the reduction of tuber numbers, we recommend the combination of herbicide treatment, soil cultivation and competition by cover crops.