Efficacy of pre- and post-emergence herbicides with and without weeding in forage cowpea (Vigna unguiculata)

A field experiment was conducted at Forage Research and Management Centre of the National Dairy Re- search Institute, Karnal, Haryana during the rainy season (kharif) of 2014 on sandy clay loam soils, to find out cost-effective weed-control method in forage cowpea [Vigna unguiculata (L.) Walp.]. Application of pendimethalin 1.0 kg/ha as pre-emergence followed by 1 hand-weeding (HW) 40 days after sowing (DAS) resulted in the lowest weed density, weed dry matter and the highest weed control efficiency, herbicide efficiency index and weed-man- agement index and was followed by imazethapyr 0.075 kg/ha followed by hand-weeding (HW) at 40 DAS due to the efficient control of dominant weed Trianthema monogyna. Uncontrolled weeds reduced the seed yield by 43% compared to weed-free treatment. Pendimethalin @ 1.0 kg a.i./ha + 1 HW at 40 DAS recorded maximum seed yield, net returns and benefit: cost ratio.