Weed management in maize (Zea mays L.) through 4-hydroxyphenylpyruvate dioxygenase inhibitor herbicide with or without a methylated seed oil adjuvant

The results of a field experiment conducted during winter (rabi) season of 2017-18 at Varanasi to evaluate the bioefficacy of a post-emergence herbicide against weeds and its impact on the yield of maize (Zea mays L.) are reported. The experiment comprised eight weed control treatments viz. topramezone at 20.16, 25.20 and 50.40 g ha⁻¹, topramezone at 20.16 and 25.20 g ha⁻¹ with methylated seed oil (MSO) adjuvant, 2,4-D at 500 g ha⁻¹, hand weeding at 20 and 40 d after sowing (DAS) and unweeded control. Post-emergence application of topramezone @ 25.20 g ha⁻¹ +MSO registered the lowest accumulation of dry matter for all weeds with the highest weed control efficiency and recorded grain yield of 47.12 q ha⁻¹ which was comparable with the hand weeding at 20 and 40 DAS (49.41 q ha⁻¹). Although the maximum seed yield was found in hand weeding treatment, the net return (Rs. 65,214 ha⁻¹) and benefit: cost ratio (3.14) were the maximum in treatment with post-emergence application of topramezone 25.20 g ha⁻¹ +MSO adjuvant.