Impact of weed control on sheath blight incidence and productivity of direct seeded rice (Oryza sativa L.)

A field experiment was conducted at shealth blight disease Ludhiana during kharif 2009 and 2010 to study the effect of weed control on and grain yield of direct seeded rice. Sheath blight incidence was the highest in unweeded control which was at par with pre-emergence application of butachlor 1.50 kg, thiobencarb 1.50 kg, anilofos 0.375 kg, pretilachlor 0.75 kg, oxadiargyl 0.09 kg & pyrazosulfuron ethyl 0.015 kg ha⁻¹ but recorded significantly higher as compared with pendimethalin 0.75 kg ha⁻¹. Post-emergence application of bispyribac 0.025 kg ha⁻¹ after different pre-emergence herbicides significantly reduced disease incidence as compared with their alone application and were at par with two hand weedings. Two hand weedings recorded the highest grain yield which was at par with herbicidal treatments of post-emergence use of bispyribac 0.025 kg ha⁻¹ after either of preemergence herbicides pendimethalin, butachlor, thiobencarb and oxadiargyl during both the years of study.