grass weeds control in transplanted rice with cyhalofop-butyl

This experiment was performed to determine the appropriate dose of cyhalofop-butyl (cb) for controlling grass weeds in transplanted rice. cb at four doses, including 50, 100, 150, and 200 g ai/ha was investigated and compared with current herbicides in rice at recommended doses. the results showed that cb 100, 150, and 200 g ai/ha significantly reduced the density and dry matter of echinochloa crusgalli (l.) p. beauv. and paspalum distichum l. over the weedy check; the minimum control efficacy of cb at these doses was 73.3 and 88.3% for e. crusgalli density and dry matter reduction, respectively, and for p. distichum, it was 80% for density and dry matter reduction. applying cb at all doses (50- 200 g/ha) showed no crop injury symptoms on rice plants. the highest grain yield was obtained by hand weeding, cb 150 g ai/ha, and tiobencarb treatments, with 5180, 5106, and 5051 kg/ha, respectively. cb 200 g ai/ha was on par with cb 150 g ai/ha, and there was no significant variation between cb 100 and 200 g ai/ha in rice grain production. finally, it was found that the application of cb 100 g ai/ha is an efficient grass weed control practice for improving the rice yield.