Seasonal incidence of Brevicoryne brassicae and Plutella xylostella on Brassica oleracea in Rohtak District

The maximum population of Brevicoryne brassicae was recorded 348 aphids/plant in 47^th SW of year 2013–14 when the temperature range were 10.7–25.1°C and RH 38–78% and 332 aphids/plant in 9^th SW in year 2014–15 when the temperature ranged and RH observed 10.1–25.8°C and RH 4080%, respectively. The maximum population of Plutella xylostella in year 2013–14 were recorded 10.80/plant in 5^th SW where temperature range and RH were 10.1–24°C and 52–92% while in year 2014–15 slight increase in the population was observed i.e 11.40/plant in 6^th SW where temperature range was 11.8–27.4°C and RH 53–91%. The population of B. brassicae had significant positive influence of maximum temperature, minimum temperature and wind speed while RH and morng RH _evng showed negative influence on them. Rainfall did not show any influence on aphid populations during both observed seasons 2013–2015. Similarly, population of P. xylostella had significant positive correlation with maximum and minimum temperatures during both the years; RH and RH had negative significant correlation while rainfall and wind speed had positive morng evng non-significant correlation.