Bioefficacy of pre- and post-emergence herbicides in direct-seeded rice in Central Punjab

Field experiments were conducted during Kharif season of 2007 and 2008 at Punjab Agricultural University, Ludhiana to evolve suitable combination of pre and post-emergence herbicides for effective weed management in direct-seeded rice under unpuddled conditions. Results indicated that during 2007, integration of post-emergence application (30 Days after sowing) of bispyribac (25 and 30 g/ha) or azimsulfuron (20 g/ha) with pre-emergence application of pendimethalin 0.75 kg/ha, pretilachlor 0.5 kg/ha and thiobencarb 1.25 kg/ha provided effective control of weeds and produced significantly higher grain yields than unweeded (control) treatment. During 2008 also, integration of pre-emergence application of pendimethalin 0.75 kg/ha or oxadiargyl 0.90 g/ha with post-emergence application of bispyribac 25 kg/ha, azimsulfuron 20 g/ha and 2,4-D 0.5 kg/ha resulted in significant reduction in dry matter of weeds and increased grain yield as compared to alone application of pendimethalin 0.75 kg/ha. Pre-emergence application of flufenacet 80 g/ha and early post-emergence application of penoxsulam 30 and 35/g ha were found ineffective for controlling weeds.