Abstract

Finding alternative herbicides has become imperative after termination of the importation of Paraquat, which has been used for controlling weeds in sugarcane mixing with Diuron. This study evaluates the effects ofherbicide, Glufosionate Ammonium 150g./l WSC (Basta) mixed with Diuron 80% WP on weed control insugarcane.

A series of field experiments was conducted at the Sugarcane Research Institute (SRI), Uda Walawe and in farmers fields at Sevanagala, Sri Lanka, during 2013-2014. The effect on weed control of three dosage ratesof Basta (1.4l/ha, 1.7l/ha and 1.9l/ha) each mixed with Diuron 80% WP (3.5 kg/ha), were examined and compared with Paraquat 65g/l EC 6l/ha mixed with Diuron 80% WP 3.5 kg/ha. In farmers’ fields, the rates of the Basta mixed with Diuron3.5kg were revised to 0.75 l/ha, 1.0 l/ha, 1.25 l/ha and 1.5 l/ha. The effects of the herbicides on weed knockdown, residual activity and crop phytotoxicity were evaluated by rating visually and counting live weeds. The visual ratings were presented with their standard error values and weed count data were analysed by ANOVA procedure.

All treatments of Basta + Diuron mixtures provided a more than 90% weed knock-down and satisfactory residual control beyond 7 – 8 weeks after planting (WAP). Therefore, Basta could be used as an alternative herbicide to Paraquat, in Paraquat + Diuron treatment. Diuron 80 WP 3.5kg/ha is recommended to mix with Basta at the rates of 0.75 – 1.5l/ha for early and late post-emergence application to control weeds in sugarcane. If weeds are mature or more grasses are present, a higher dosage rate of Basta i.e.1.5 l/ha has to be mixed with Diuron to get satisfactory weed knock-down. The minor scorching and discoloration of crop when Basta was applied at higher dosage rates of 1.25 l/ha and 1.5 l/ha, mixed with Diuron were negligible and disappeared within 2 – 3 weeks.