Efficacy of Metamifop against grassy weeds in direct-sown rice (Oryza sativa) and its impact on succeeding crop

Metamifop is an aryloxyphenoxypropionate herbicide that controls grassy weeds. Insufficient information is available on the dose of application of metamifop for post-emergence weed control. A field experiment was conducted during 2014-15 and 2015-16 at ICAR-National Rice Research Institute to determine the most effective dose of metamifop in direct-sown rice (Oryza sativa L.) and its impact in rice-rice cropping sequence. The treatments consisted of 4 doses of metamifop 10% EC at 75, 100, 150 and 200 g/ha along with oxyfluorfen 23.5% EC at 240 g/ha as standard check. Application of metamifop at 200 g/ha effectively controlled all the grassy weeds (weed control efficiency, 80-84%) except Leptochloa chinensis. Similar trend was observed with metamifop at 150 g/ha (weed control efficiency, 76-82%). Metamifop at 150 g/ha recorded 4.59 tonnes/ha grain yield and it was at par with metamifop applied at 200 g/ha (4.84 tonnes/ha). There was no negative effect of the herbicide treatments on the germination percentage, growth and yield of the succeeding rice crop in rice-rice cropping sequence. Therefore, metamifop 10% EC at 150 g/ha would be optimum recommendation for the control of grassy weeds in rice crop, considering the lower dose for reducing the herbicide load in the environment.