Thermal budgeting for cabbage butterfly, Pieris brassicae under controlled conditions in Kashmir Valley

Temperature has a significant influence on cabbage butterfly development and survival. This is one of the important pest on cabbage crop across the globe. This paper reflects the hypothesis of various models used to determine the lower developmental threshold of insects. In some models, the rate of isomorphy revealed that the lower developmental threshold of different stages of insects is same but the current study provides that the lower developmental threshold of each phenological stage of cabbage butterfly is not same. Therefore, Thermal budgeting for different phenological stages of cabbage butterfly revealed that survival, developmental time and developmental rate varies from one stage to another stage under controlled conditions at different temperature regimes. The per cent egg hatchability and adult survival was observed, highest at 35⁰C among the set constant temperatures. While as, per cent larval and pupal survival was recorded, highest at 25⁰C under different temperature regimes. The lower developmental threshold of 10.41, 5.00, 7.77, 11.11 ⁰C were calculated for the egg, larval, pupal and adult, respectively. The thermal constant (K) for egg, larva, pupa and adult were 68.49, 833.33, 277.77 and 555.55 degree days, respectively. The first butterfly emergence was observed on 97 Julian days. In Kashmir valley, four and half generations of cabbage butterfly was recorded in a year. This study will be useful for other butterflies/ insects to build a relationship for climate change.