Population dynamics of important insect-pests on black gram in relation to weather parameters during pre-kharif season in terai region of West Bengal, India

Abstract

Population dynamics of insect pests on black gram was studied in relation with weather parameters during pre-kharif 2018 and 2019 in terai region of West Bengal, India. The result revealed that the peak population of whiteflies (7.20/trifoliate/plant) was observed on 14th SMW in 2018, while it was 6.30/trifoliate/plant on 15th SMW in 2019. The peak population of jassids was noticed in 16th SMW in both the year and the population ranged from 4.37 to 4.57/trifoliate/plant. The aphid population started appearing on 8th SMW and increased gradually to reach highest level (24.57/10cm twig/plant and 41.90/10cm twig/plant in 2018 and 2019 respectively) on 10th SMW. The highest larval population of spotted pod borer (1.53/plant and 1.45/plant) and damage (16.07% and 16.29%) to the pod were found during 19th SMW in both the year. Correlation studies indicated that white fly, aphids and spotted pod borer larval population exhibited a significant negative correlation with temperature, relative humidity and rainfall, while Jassid population had a significant positive correlation with temperature, relative humidity and rainfall. Therefore, it can be stated that weather variables had a significant impact on population fluctuation of pest population in black gram crop.