Comparative study on efficacy of sulfonylurea herbicides and traditional recommended herbicides in transplanted rice (Oryza sativa)

The efficacy of some potent low-dose herbicides of sulfonylurea group in conjunction with other traditional recommended herbicides for control of wide-spectrum of weed flora in transplanted rice (Oryza sativa L.) field was studied during the wet season of 2004 and 2005 at Cuttack, under rainfed shallow lowland. The major weeds found were Echinochloa spp., Cyperus iria, Fimbristylis miliacea, Sphenochlea zeylanica, Ludwigia parviflora and Aeschynomene indica. Triasulfuron + Pretilachlor (9 + 500 glha) applied 7 days after transplanting was found most effective in controlling weeds and maximizing rice-grain yield (59.3). This was at par with weed- free check. There was more than 44% reduction in the grain yield of rice due to competition with weeds in the weedy plots. All the new-generation herbicides showed better control of weeds (weed-control efficiency 79.9- 95.1%) in comparison with the traditional recommended rice herbicides (weed-control efficiency 73.3-78%) and gave higher yield of rice irrespective of their dose of application.