Effect of Bensulfuron-Methyl+Pretilachlor and Other Herbicides on Mixed Weed Flora of Wet Season Transplanted Rice

Abstract

Field experiments were conducted during the wet season of 2012 and 2013 at farmer’s field of village Binuria, Sriniketan, Birbhum, West Bengal, India with rice variety ‘Swarna’ (MTU 7029) to study the effect of bensulfuron-methyl + pretilachlor and other herbicides on growth of different weed species and productivity of transplanted rice. Twelve treatments in the experiment were assigned in a randomized block design with three replications. Results revealed that rice was infested with three categories of weeds viz. grasses, broadleaved and sedges. Cynodon dactylon and Paspalum distichum among the grasses; Fimbristylis miliacea, among the sedges and Ludwigia parviflora and Commelina nudiflora among the broadleaved weeds were predominant throughout the cropping period. Bensulfuron-methyl 0.6%+ pretilachlor 6% at 60+600 g ha-1applied at 3 DAT completely controlled the grasses, broadleaved and sedges at 30 and 60 DAT except Cynodon dactylon and Paspalum distichum. However, the density, as well as dry weight of both the species were significantly reduced. Metsulfuron methyl + chlorimuron-ethyl (Almix) + azimsulfuron at 4+35 g ha-1 at 15 DAT was also quite effective in controlling broad spectrum weeds. Lower values of weed density, total weed dry weight and higher values of herbicide efficiency index and yield of rice were registered with application of bensulfuron-methyl 0.6%+ pretilachlor 6% at 60 + 600 g ha-1 at 3 DAT followed by metsulfuron methyl + chlorimuron-ethyl (Almix) + azimsulfuron at 4+35 g ha-1 at 15 DAT. Weed infestation resulted in grain yield reduction of rice to the tune of 40% Application of bensulfuron-methyl 0.6%+ pretilachlor 6% at 60+600 g ha-1 at 3 DAT or metsulfuron methyl + chlorimuron-ethyl (Almix) + azimsulfuron at 4 + 35 g ha-1 at 15 DAT appeared to be the most promising for managing mixed weed flora and obtaining higher yield of transplanted rice in the lateritic belt of West Bengal, India.