Efficacy of imazethapyr against weeds of groundnut

A field experiment was conducted during kharif season of 2008 at Livestock Farm, JNKVV, Jabalpur to study the efficacy of imazethapyr against weeds in groundnut. The experimental field was infested with grassy weeds Echinochloa colona (33.72%), Dinebra retroflaxa (24.18 %), and sedge Cyperus iria (42.09 %) at 40 DAS. The efficacy of imazethapyr as post emergence when applied between 50 to 150 g/ha was poor, which improved slightly with the increase in application rates between 200 to 300 g/ha. However, combined application of imazethapyr at lower rate 100 g/ha + chlorimuron 24 g/ha paralysed the weed growth identically (84.82 %) to that of hand weeding twice (87.84 %). The Latter treatment also attainded the superior values of yield attributes (pods/plant 13.5, kernels/pod 2.5), higher pod (12.69 q/ha) and haulm (14.10 q/ha) yields and found more remunerative as it fetched the maximum values of net monetary returns (Rs 13880 /ha) and benefit : cost ratio (1.8) as compared to recommended practices of weed control viz., hand weeding twice which recorded the lower values of NMR (Rs 9769 /ha) and B:C ratio (1.4) due more cost of weed control.