Greengram, Herbicide residues, Imazethapyr, Economics, Weed management 

A field experiment was conducted during three consecutive summer seasons (2022, 2023 and 2024) at different agroclimatic zones of Punjab, India, to study the effect of weed management practices on weeds and on summer greengram productivity and economics. A randomised block design comprising of 8 treatments with 4 replications was used. Hand weeding (HW) twice resulted in the lowest weed density and biomass, highest weed control efficiency (86.6% at 40 DAS and 84.0% at harvest) and highest greengram yield, which was statistically at par with post-emergence application (PoE) of imazethapyr 75 g/ha at 15 and 25 days after seeding (DAS). However, net return was higher with imazethapyr 75 g/ha PoE at 15 DAS and 25 DAS than HW twice. Imazethapyr 75 g/ha PoE at 15 DAS recorded the highest B:C (3.16). The residues of imazethapyr 50–75 g/ha PoE in grains at harvest were below the quantification limit (0.01 µg/g), confirming the safety of imazethapyr usage at recommended doses. It was concluded that effective and economical weed management in summer greengram, under different agroclimatic zones of Punjab, can be achieved, without any residual effects, with imazethapyr 75 g/ha PoE at 15 or 25 DAS.