Bioefficacy of new herbicide fluazifop-p-butyl for grassy weed management in groundnut and carry-over effect on succeeding finger millet

Major grassy weed flora observed during 2010 and 2011 mansoon season on red sand loam soil of Bangalore were Echinochloa colona, Digitaria marginata, Eleusine indica, Dactyloctenium aegyptium and Cynodon dactylon. The new graminicide fluazifop-p-butyl at 134 and 167 g a. i./ha lowered the density and growth of grasses, nutrient uptake by weeds considerably as compared to other treatments. Application of fluazifop-p-butyl 13.4 EC134 to167 g a. i./ha @18–20 DAS gave higher pod yield (1651 to 1531 kg/ha) and was on par with hand weeding (1757 kg/ha), imazethapyr 10 SL 100 g a. i./ha (1574 kg/ha) and pendimethalin 30 EC 750 g a. i./ha @ 3 DAS (1469 kg/ha). Unweeded control significantly lowered pod yield by 39% as compared to hand weeding. Fluazifop-p-butyl at 167 to 335 did not cause phytotoxicity to groundnut and did not leave residual toxicity on succeeding finger millet grown after 155 days of herbicide application during two years of experiment. Thus, herbicides were cheaper, used less energy inputs, lowered nutrient loss, provided higher energy use efficiency and higher B: C than manual weeding.