Efficacy, crop safety, and implications of premix herbicide combination (metamifop 8%, imazethapyr 4%, and imazamox 3% ME) in groundnut and its residual effect on succeeding green gram

Timely weed management, through the use of pre and post-emergence herbicide, is crucial for maximizing economic yield and oil content in groundnut cultivation. However, the limited availability of effective herbicides, coupled with increasing weed resistance and concerns of crop phytotoxicity, continues to challenge sustainable weed management in groundnut. To address this issue, a two-year field trial (2021 and 2022) was conducted to evaluate the impact of post-emergence herbicides on the bio-efficacy, phytotoxicity, and profitability of groundnut cultivation. Results revealed that treatment Metamifop 8% + Imazethapyr 4% + Imazomox 3% ME + Ammonium Sulphate @ 1250 mlha-1 (T6) has significantly reduced the weed density (79-95, 78-86 and 80-90%), weed dry weight (79-86, 87-93 and 77-93%) andweed control efficiency(79-90, 77-93, 77-91%) at 15, 30 and 45 DAA in comparison to unweeded control. It also shown superior performance in both the years among the herbicidal treatments in terms of plant height (33-34 cm), no. of branches per plant (6.9-7.6), no. of pods per plant (8.8-9.3) and seed yield (1950-1986 kg ha-1) which are on par with weed-free control (35.6-36.3 cm, 7.3-8.0 no plant-1, 9.3-9.7 no. plant-1, 2153-2028 kg ha-1). The treatment T5has recorded a similar trend in terms of plant height (33-33.8 cm) and grain yield (1942-1978 kg ha-1), indicating that the higher herbicide dose effectively controlled weeds and reduced crop-weed competition. The economic analysis revealed that the treatment Metamifop 8% + Imazethapyr 4% + Imazomox 3% ME + Ammonium Sulphate @ 1000 ml/ha (T5)has recorded higher net returns and B: C ratio, which is followed by T6. The studies concluded that the Metamifop 8% + Imazethapyr 4% + Imazomox 3% ME + Ammonium Sulphate @ 1000-1250 ml ha-1 is highly effective, non-phytotoxic, and economically viable for post-emergence application in groundnut: providing a practical solution to the challenge of weed management.