Weed Control by Single Post-emergence Combination Herbicide Florpyrauxifen-Benzyl Plus Cyhalofop Butyl in Aerobic Rice

Florpyrauxifen benzyl + cyhalofop butyl is a new combination herbicide product which has proven to control wide range of weed flora. A two year study was planned in the wet and dry seasons of 2015-16 and 2016-17 to evaluate effective dosage of early post-emergence combination herbicide product florpyrauxifen benzyl + cyhalofop butyl (120; 150 and 180 g ha-1) to manage weeds in aerobic rice and study the residual effect on succeeding maize crop. The results revealed that Barnyard grass (Echinochloa crusgalli) followed by Dinebra retroflexa (viper grass) dominated among the weed flora. The combination product florpyrauxifen benzyl + cyhalofop Butyl 180 g ha-1 contributed to significantly lower density and dry biomass accumulation by grass and broadleaf weeds as compared to weedy check; however its efficacy was poor on sedges at 60 days after sowing (DAS). Highest weed control efficiency was recorded by florpyrauxifen benzyl + cyhalofop butyl 180 g ha-1. The highest yield (4100 and 3420 kg ha-1) was in plots treated with florpyrauxifen benzyl + cyhalofop butyl at 180 g ha-1 and the lowest yield was in florpyrauxifen benzyl 31.25 g ha-1 (3280 and 2870 kg ha-1) followed by bispyribac sodium 25 g ha-1 (3320 and 2940 kg ha-1) in 2015 and 2016, respectively. Weed infestation decreased the rice yield by nearly about 69% in 2015 and 72% in 2016. A strong negative relationship between rice yield and weed biomass was seen which explained 87 and 91% variation in grain yield at 30 and 60 DAS. Combination product florpyrauxifen benzyl + cyhalofop butyl at all rates did not have any residual toxic effect on succeeding maize. Based on the findings, it can be concluded that aerobic rice weeds can be controlled by applying early post-emergence application of combination product florpyrauxifen benzyl + cyhalofop butyl 150 to 180 g ha-1 without any residual toxicity.