Abstract

Field experiments were conducted at Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai, to evaluate the new herbicide Bispyribac sodium in transplanted rice on yield and weed control efficiency in transplanted rice varieties ASD 16 and ADT 37 during Kharif 2011 and 2012, respectively. Seven treatments were included in a Randomized Block Design and replicated four times. The treatments consisted of pre– emergence application of Butachlor @1500 g a.i. ha -1 , post emergence application of Bispyribac -sodium 10 SC at 25, 35 and 50 g a.i. ha -1 , weed free, hand weeding twice and unweeded check. The results revealed that the total weed population and dry weight under Bispyribac sodium at 25 g a.i. ha-1 were on par with the higher doses of Bispyribac sodium at 35 and 50 g a.i.ha -1 during both the years of study. The weed control efficiency and weed index under Bispyribac sodium at lower dose were also comparable with that of higher doses indicating the sufficiency of Bispyribac sodium at 25 g a.i.ha -1 for effective weed management in transplanted rice. The effect of Bispyribac sodium at 25 g a.i. ha -1 on producing tillers and panicles was also on par with that of higher doses and twice that of hand weeding and found to be significantly superior to Butachlor application. Post emergence application of Bispyribac sodium at 25 g a.i. ha -1 recorded a grain yield of 6838 and 6510 kg ha -1 during 2011 and 2012, respectively, which were found to be on par with higher doses of Bispyribac sodium, twice hand weeding and weed free; and significantly higher than Butachlor application. Higher economic benefits like net income and benefit-cost ratio were also associated with the application of Bispyribac sodium at 25 g a.i. ha -1 than all the other weed managemnet treatments

Keywords: Rice, Bisbyribac sodium, Weed, Grain yield and economics