Population dynamics of mustard aphid Lipaphis erysimi (Kalt.) In relation to weather parameters

Mustard aphid Lipaphis erysimi (Kalt.) is a most serious pest, considered as a limiting factor in the cultivation of mustard crop causing 35-96% reduction in yield depending upon weather conditions. Studies were conducted on the population dynamics of mustard aphid on mustard (Brassica juncea L.) variety Varuna in relation to weather parameters (Temperature and Relative humidity) in rabi cropping season during 2015-16 at experimental field of Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh (Uttar Pradesh). The natural appearance of mustard aphid was observed from 3rd standard week and lasted up to 11th standard week. The study revealed that population of mustard aphid reaches its peak in 7th standard week showing significant positive correlation with maximum temperature and negative correlation with relative humidity.