Tien jaar Knolcyperus (Cyperus esculentus L.) in Nederland

Yellow nutsedge ( Cyperus esculentus L.) was first recorded in 1981 as an agricultural pest. A considerable number of fields was found to be infested. Because the species is very damaging to agriculture legal measures were taken to restrict the dispersion and promote the control of the weed. During the eighties a monitoring system yielded much information on the development of the nutsedge populations. After 1985 the legal measures led to a decline of the species; however, the eradication was not successful on the national level. Failure in obtaining sufficient financial support led to the abandonment of the legal measures. Yellow nutsedge is now increasing again and it is expected that it will reach the status of a common weed in agriculture. Attention of botanists is asked for this interesting, invasive weed.