Population buildup of mustard aphid, Lipaphis Erysimi (Kalt.) on Indian mustard in relation to same abiotic factors

To study the population buildup of mustard aphid, Lipaphis erysimi (Kalt.) on Indian mustard, the field experiments were conducted at Meerut, Uttar Pradesh, during 2010–11 and 2011–12. Studies revealed that the incidence of mustard aphid started in the 51^st standard week i.e. 3^rd week of December during both the years and reached to peak level in 5^th standard week i.e. 1^st week of February and 8^th standard week i.e. 4^th week of February, during 2010–11 and 201112, respectively. During the period of maximum activity period of mustard aphid the maximum temperature, minimum temperature and mean relative humidity ranged from 13.35 to 24.71^OC, 3.41 to 9.58^OC and 51.14 to 72.13 per cent, respectively. The studies reveled positive correlation with maximum temperature that is non significant during 2010–11 and significant during 201112, positive and non significant correlation existed with minimum temperature and a negative and non significant correlation was observed with mean relative humidity during both the years.