New herbicides, Transplanted rice

An experiment was conducted in randomized block design with 7 treatments comprising butachlor 1.5 kg/ha at 5-7 DAT, bispyribac-sodium 25 g ha at 15-20 DAT, bispyribac-sodium 35 g/ha at 15-20 DAT, bispyribac-sodium 50 g/ha at 15-20  DAT, weed-free, until harvest, two hand weedings at 20 and 40 days after transplanting and unweeded control. Results revealed that application of bispyribac-sodium 50 g/ha at 15-20 DAT resulted in significantly higher grain yield (5.70 t/ha), which was at par with bispyribac-sodium  35 g/ha at 15-20 DAT. Number and dry weight of weeds was also minimum in these treatments. However, the highest grain yield (6.05 and 6.55 t/ha) was obtained from weed-free treatment. Significantly lower weed density (9-10/m2), weed dry weight (12.5-13.7 g/m2), weed persistence index (0.03) and weed competition index (8.05-12.55) were recorded in the plots where bispyribac-sodium 35 g/ha at 15-20 DAT was applied. Significantly higher weed control efficiency and herbicidal efficiency index were recorded with bispyribac-sodium 35 g/ha at 15-20 DAT.