Clomazone was applied preplant incorporated, preemergence, delayed preemergence, or postemergence and compared to pendimethalin, quinclorac, and thiobencarb for control of barnyardgrass in rice. Seven days after the clomazone postemergence application, all clomazone treatments except those applied postemergence controlled barnyardgrass ≥ 86%. At 49 d after the postemergence application, control of barnyardgrass with 0.56 and 0.67 kg/ha clomazone postemergence improved to 92 and 93%, respectively. Clomazone and quinclorac applied delayed preemergence generally controlled barnyardgrass less than 70%. Visible injury to rice was ≤ 18% 7 d after emergence and had declined to less than 10% when evaluated 7 d after postemergence treatments. Rice yields were higher with all treatments compared to the nontreated control.
