Invasion and occurrence of green gram weevil, Pachytychiius mungonsis Marshall on black gram in hill region of North Western Himalayas and its control

Abstract

Studies were carried out on the incidence and occurrence of green gram weevil, Pachytychiius mungonsis on black gram crop in Kullu and Mandi districts of Himachal Pradesh during Kharif 2018 and 2019. It was revealed that among the different localities surveyed, maximum plant infestation to black gram plants was recorded in Garsa village (42.33-59.00%) followed by Kolibehar (37.00 to 54.16%) followed by Thrash with 35.00-52.00 per cent plant infestation whereas Jhiri village recorded 34.00-47.00 per cent plant infestation. The pod infestation in the respective villages varied from 25.08-32.51, 18.10-31.60, 16.51-29.08 and 14.30-24.55 per cent, respectively. Results based on the 2 years data for the control of this pest revealed that among the various treatments used, a spray of quinalphos @ 2ml/L resulted in the best control of green gram weevil with least pod infestation (1.41 per cent) followed by cypermethrin @ 0.75ml/L (T1) with 1.98 per cent pod infestation after 15 days of spray. Also these two chemicals resulted in lowest percentage of plants having weevil infested pods i.e., 2.47 and 3.46, respectively. Data on the yield analysis of black gram crop revealed that single spray of quinalphos @ 2ml/L when given after 45 days of
seed emergence, was found to be the most effective and economic for the control of green gram weevil with the highest yield (17.06 q/ha) and with a net gain of Rs.18.46 per rupee invested followed by cypermethrin @ 0.75ml/L with yield of 16.56 q/ha and a net gain of Rs.18.15 per rupee invested.