Bio-efficacy of quinclorac and clefoxydim for the control of weeds in rice nursery.

摘要

The bioefficacy of quinclorac (Facet SC, at 125, 187.5 and 250 g a.i./ha) and clefoxydim (Tetris EC, at 5, 75 and 100 g a.i./ha) for the control of weeds in rice (cv. IET-4786) nursery, in comparison to hand weeding and anilofos at 375 g a.i./ha, was evaluated in an experiment conducted during the kharif season of 2000, in Kalyani, West Bengal, India. Quinclorac and clefoxydim were applied at 2-4-leaf stage of the weeds, while anilofos was applied at 7 and 15 days after sowing (DAS) of rice. Quinclorac at 250 g a.i./ha gave the highest weed control efficiency (WCE) of 86.65% with the lowest weed dry matter (1.94 g/m2) at 28 DAS. It showed no phytotoxicity to rice and the germination percentage of rice was also not at all affected (97-98%). Clefoxydim at 100 g a.i./ha recorded the highest WCE of 85.41% at 28 DAS; although lower doses (50-75 g a.i./ha) of this herbicide were also effective in controlling the weeds. Clefoxydim also had no negative effect on germination percentage (96-99%) and was not toxic to rice.