Evaluation of new-generation herbicides for efficient weed management in Lentil (Lens culinaris Medik.) under rainfed condition of North East India

Abstract

A field experiment was conducted during the rabi season of 2023-24 at the Research Farm, Andro, Central Agricultural University (CAU), Imphal, to evaluate pre- and post-emergence herbicides and their sequential applications for weed management in lentil. The trial followed a randomized block design with nine treatments and three replications. Treatments included pendimethalin 750 g a.i. ha⁻¹ (pre-emergence); imazethapyr 50 g a.i. ha⁻¹ (pre-emergence); pendimethalin 750 g a.i. ha⁻¹ (pre-emergence) followed by quizalofop-p-ethyl 100 g a.i. ha⁻¹ at 20 DAS; oxyfluorfen 150 g a.i. ha⁻¹ (pre-emergence) followed by propaquizafop 100 g a.i. ha⁻¹ at 20 DAS; imazethapyr 50 g a.i. ha⁻¹ at 20 DAS (post-emergence); quizalofop-p-ethyl 100 g a.i. ha⁻¹ at 20 DAS (post-emergence); carfentrazone-ethyl 15 g a.i. ha⁻¹ at 20 DAS (post-emergence); unweeded control; and weed-free check (two hand weedings). Weed management significantly influenced growth, yield, weed control efficiency (WCE), and weed index (WI). Sequential application of pendimethalin 750 g a.i. ha⁻¹ (pre) followed by quizalofop-p-ethyl 100 g a.i. ha⁻¹ at 20 DAS produced the tallest plants (42.5 cm), highest pods per plant (36.8), seed yield of 1,283 kg ha⁻¹, WCE 61.6%, and WI 27.2%. Carfentrazone-ethyl 15 g a.i. ha⁻¹ at 20 DAS yielded 1,413 kg ha⁻¹ with WCE 60.8% and WI 27.5%, comparable to the weed-free check (1,763 kg ha⁻¹; WCE 100%; WI 0%). Quizalofop-p-ethyl 100 g a.i. ha⁻¹ at 20 DAS alone was less effective (816 kg ha⁻¹; WCE 0%; WI 53.7%), while the unweeded control recorded the lowest yield (983 kg ha⁻¹; WCE 0%; WI 44.3%). Economic analysis revealed highest net returns (₹78,866 ha⁻¹) and B:C ratio (1.63) under carfentrazone-ethyl, followed by pendimethalin + quizalofop (₹66,420 ha⁻¹; B:C 1.32). The unweeded control had the lowest returns (₹44,520 ha⁻¹; B:C 0.96). These findings indicate that sequential or broad-spectrum herbicides, particularly carfentrazone-ethyl and pendimethalin followed by quizalofop-p-ethyl, ensure effective weed management and economically viable lentil production under North-East Indian conditions.