Effect of early post-emergence herbicide for control of weeds in winter irrigated upland cotton (Gossypium hirsutum)

A study was carried out to evaluate the effect of trifloxysulfuron with and without adjuvant against weeds in upland cotton (Gossypium hirsutum L.) during the winter seasons of 2003–04 and 2004–05 at the Tamil Nadu Agricultural University, Coimbatore. Weeds, viz. Trianthema portulacastrum L., Chloris inflata Link; syn. C. barbata Sw. and Cyperus rotundus L., were the dominant weeds of the experimental field. Trifloxysulfuron effectively controlled T. portulacastrum and C. rotundus. Trifloxysulfuron @ 10 and 20 g/ha with and without adjuvant provided 85 to 91% weed-control efficiency compared to unweeded control. Among the treatments, the maximum cotton yield of 16.89 and 17.96 q/ha was observed in trifloxysulfuron 10 g/ha + adjuvant during the winter season of 2003–04 and 2004–05 respectively. Minimum seed-cotton yield of 8.97 and 8.76 q/ha was obtained in unweeded control in first and second year.