Performance of some pre emergence herbicides against weeds in winter rice.

An experiment was conducted at Bangladesh Rice Research Institute, Gazipur, during winter season 2009 to evaluate the weed control efficiency of some pre-emergence herbicides in transplanted rice. Among the treated herbicides, four were from pretilachlor, two from butachlor, one from oxadiazon and one from bensulfuron methyl + acetachlor group. One herbicide from pretilachlor and one from oxadiazon group were used for standard comparison as well. No phytotoxic effects were observed on the treated plots. Echinochloa crusgalli was found as the most dominating weed in all the treated rice plots and the most prevalent weed was Scirpus maritimus. Among the evaluated herbicides, Rigid 50 EC (pretilachlor) @ 1L, Alert 18WP (bensulfuron + acetachlor) @ 400g, Kildor 5G (butachlor) @ 25kg, Bigboss 500EC (pretilachlor) @ 1L, Rifit 500EC (pretilachlor) @ 1L, Ravchlor 5G (butachlor) @ 25kg, Succour 50EC (pretilachlor) @ 1L and Topstar 80WP (oxadiazon) @75g ha -1 showed above 80% weed control efficiency. Similarly, the grain yields were above 4 t ha -1 in the aforesaid treatments which were comparable to the standard check; however, weed free plots gave the highest grain yield as anticipated.