Efficacy of New Post Emergence Herbicide 'Rinskor’ In Wet Seeded Rice (Oryza sativa L.)

Abstract

A field experiment was conducted at CSK HP Krishi Vishvavidyalaya, Rice and Wheat Research Centre, Malan during kharif 2016 to find out the bio-efficacy of new herbicide rinskor 2.5% EC in wet seeded rice (sowing of sprouted rice seeds in puddled fields). Four herbicide treatments comprising single herbicide rinskor at two doses (31.25 and 37.5 g a.i./ha 4-7 leaf stage of weeds), bispyribac sodium 30 g a.i./ha 3-4 leaf stage of weeds, and sequential application of pyrazosulfuron ethyl (25 g 3-5 days after sowing; DAS) followed by (fb) metsulfuron methyl + chlorimuron ethyl (4 g 25-30 DAS) were evaluated along with weed free (three hand weedings; 20 40 & 60 DAS), two hand weedings and weedy check. The crop was heavily infested with weeds (288.7/m²) viz., Monochoria vaginalis, Commelina benghalensis, Digitaria sanguinalis, Paspalum paspalodes, Echinochloa colona, E. crusgalli, Eleusine indica, Phyllanthus niruri and Setaria glauca, thus recording significantly more dry matter of both grass and broadleaf weeds compared to different weed control treatments. The weed index (increase in yield over weedy check) of different weed control treatments recorded values of 23.1 to 43.6 per cent; highest being with rinskor 37.5 g/ha. Rinskor at both the doses, bispyribac and sequential application of pyrazosulfuron ethy Jb metsulfuron ethyl + chlorimuron behaved alike in reducing weed density and were at par with two hand weedings. Rinskor and bispyribac were statistically equally effective in reducing dry matter of broad leaf weeds and were at par with weed free treatment. The significant effect of weed control treatments was reflected in growth and yield attributes of the crop. Rinskor 37.5 g/ha recorded tillering (336/m²) and panicles (320/m²) and grain (4.35 Mg/ha) at par with its lower dose (31.25 g/ha) and weed free treatment (weeding at 20,40 & 60 DAS). Thus, the new herbicide, rinskor 37.5 g/ha may be applied at 4-7 leaf stage of weeds (25 DAS) for efficient control of mixed weed flora in wet seeded rice.