Bioefficacy and persistence of etiioxysulfuron in rice

摘要

Although herbicides provide effective weed control, yet some herbicides pose serious health and environment threats. Ethoxysulfuron [3-(4, 6-dimethoxyoyrimidin-2-yl)-l-(2-ethoxyphenoxysulfonyl) urea] belongs to sulfonylurea group having a toxicity class of III and used as a selective herbicide. It acts by reducing the levels of three branched-chain aliphatic amino acids. Bio-efficacy and persistence of ethoxysulfuron (60% WG) sprayed at 15, 17.50, 18.75 and 20 g ha-1 doses as post-emergence were evaluated in transplanted rice. Among the herbicides all the herbicidal treatments enhanced the grain yield by 50% over weedy check and were statistically at par with each other The grain yield of rice crop was the highest under weed free situation followedby almix and ethoxysulfuron application. There were no phytotoxic symptoms of ethoxysulfuron on transplanted rice. Soil and crop samples were analyzed to see persistence of ethoxysulfuron. Residues were found below <0.001 ng g~(-1) in soil, grains and straw at harvest at 15 to 20 g ha-1 doses, respectively. This showed fast dissipation of ethoxysulfuron in soil and plants and thus do not pose environmental risk at applied rates.