SUBLETHAL EFFECTS OF CHLORSULFURON ON BLACK BINDWEED (POLYGONUM-CONVOLVULUS L)

Effects of the herbicide chlorsulfuron on growth and reproduction of b lack bindweed (Polygonum convolvulus L.) plants were investigated in a controlled environment chamber and a greenhouse over a full life cycl e. Biomass of P. convolvulus was stimulated at 0.4 g a.i. ha(-1), but at higher doses it was reduced compared with controls. Leaf production of plants treated with 1.6 g a.i. ha(-1) was initially totally inhibi ted, but these plants resumed leaf production 10 days after treatment. Chlorsulfuron treatment resulted in higher proportions of small and l arge leaves compared with controls. Because the life-span of the plant s increased with increasing doses of chlorsulfuron, seed production wa s not affected at doses up to 1.6 g ha(-1), even though significant ef fects were found on both biomass and leaf production At rates of 1.6-4 g a.i. ha(-1) seed production decreased. Plant mortality was low in t his study, reaching 33% at the highest rate of chlorsulfuron.