Influence of post-emergence herbicides on weeds and productivity of garden pea (Pisum sativum) under mid hill conditions of Himachal Pradesh

To standardize dose and time of application of post-emergence herbicides in garden pea (Pisum sativum var. hortense) under mid-hills of Himalaya, eleven treatments viz., imazethapyr 100 and 150 g/ha at 20 and 40 DAS, quizalofop 25 and 37.5 g/ha at 20 DAS, isoproturon 1.0 and 1.25 kg/ha at 40 DAS, pendimethalin 1.5 kg/ha (preemergence), hand-weeding twice (30 and 60 DAS) and unweeded check were tested during the winter season of 2005–06 and 2006–07 at Palampur. The major weed flora was Phalaris minor, Avena fatua and Vicia sativa in both the years. Post-emergence application of all the herbicides except quizalofop 25 g/ha at 20 DAS and hand weeding twice resulted in significantly lower dry weight of weeds over pre-emergence pendimethalin 1.5 kg/ha. Higher doses of all the post-emergence herbicides were superior to their lower doses. Significantly lower dry matter accumulation of all the weed species and highest weed control efficiency were obtained with imazethapyr 150 g/ha (40 DAS). Imazethapyr 150 g/ha at 40 DAS resulted in maximum plant height, dry matter accumulation, crop growth rate, relative growth rate, nodule count and weight and green pod and haulm yields. Weeds in untreated check reduced pea pod yield by 56.8% over the best post-emergence herbicidal treatment (imazethapyr 150 g/ha at 40 DAS) in 2005–06 and 60.1% in 2006–07.