The Results of Pre-emergence Herbicide Screening Trials for Sugarcane in Natal

The results of seven pre-emergence herbicide screening trials involving 27 chemicals are presented. The experiments, which were conducted over a fouryear period, differed with respect to soil moisture conditions, soil type and prevailing weed flora. Special attention was directed to the control of Cyperus esculentus, C. rotundus and grasses. Mean visual assessmenlts of control of species or speciesgroup are presented for each experiment. Two chemicals, C.P.50144 (Alachlor) and C.P.44939 gave consistently good results. C.P.50144 had a wide spectrum of broad-leaf weed and grass control, the latter being excellent even under relatively dry conditions. The product was also active on C. esculentus. No phytotoxicity to sugarcane from C.P.50144 was recorded. C.P.44939 gave outstanding control of C. esculentus, C. rotundus and the grasses, including Panicum maximum. Phytotoxicity to cane has not been fully evaluated.