author(s)
Purnima Das, Rituraj Saikia, Lakshmi Kanta Hazarika, Athar Nishat Islam and Priyanka Saikia

abstract
The study on life cycle duration of lac insect revealed a minimum duration of 149 days during summer 2016 and the highest of 199 days during winter 2017. Variation of life span was more in Kerria lacca 149-199 days but in the case of K. chinensis, life span varied from 155-194 days. The correlation analysis of weather parameters with life cycle duration of lac insect showed a highly significant positive correlation (r = 0.85**) with morning relative humidity and significant negative correlation (r = -0.68*) with total rainfall. The multiple linear regression analysis showed that total rainfall, maximum temperature, bright sunshine hours, morning and evening relative humidity were the major weather parameters which affected the life cycle duration of Kerria spp and these five weather parameters exhibited the highest Adjusted Coefficient of Determination of 86.37 per cent and explained 93.94 per cent of the total variation occurring in the crop growth period.