Seasonal incidence of aphid and their natural enemies on mustard from terai region of West Bengal

Seasonal incidence of mustard aphid, Lipaphis erysimi was studied along with the impact of natural enemies and the meteorological parameters on the fluctuation of aphid population. The natural enemies like coccinellids and syrphids were found to register strong positive association with the population build up of mustard aphid while the meteorological parameters failed to establish any strong influence on the population fluctuation of aphid. The infestation of Lipaphis erysimi (Kalt.) on mustard commenced from 3^rd SW and 1^st SW and the maximum population of 53.2 aphids/ top 10 cm central shoot and 59.47 aphids/ top 10 cm central shoot were observed on 8^th SW in both year during 2017-18 and 2018-19, respectively.