Efficacy of Herbicides in Wet Direct-sown Summer Rice

Major weed nora associatcd with wet direct-sown summer rice during the dry season comprised mainly Echinochloa colona (9.5%,), Cyperus defformis (30.2%), Fimbistrylis miliacea (27.0%,), Sphenochlea zeylanica (15.8%) and Ludwigia parviflora (17.5%.). Pyrazosulfuron-ethyl (25 g ha⁻¹) applied at 10 days after sowing was most effective in controlling the weeds (95.6%) and maximizing rice grain yield (5.72 t ha⁻¹). This was at par with hand wceding twice at 20 and 40 DAS in terms of weed control efficiency and grain yield. Pyrazosulfuron ethyl (20 g ha⁻¹) applied at 10 DAS, pretilachlor + safener (750 g ha⁻¹) applied at 7 DAS and fentra/amide (120 g ha⁻¹) applied at 7 DAS also showed good suppression of weeds with weed control etliciency of 93.7, 91.4 and 90.5%, respectively. There was more than 45%, reduction in the grain yield of rice due to competition with weeds in weedy plots.