Biology and seasonal fluctuation of Henosepilachna vigintioctopunctata Fabr. on brinjal under Terai region of West Bengal

Abstract

Epilachna beetle (Henosepilachna vigintioctopunctata Fabr.), in Terai region was found active from April to middle of October llnd highest population waS recorded (8.14 beetle/plant) during middle of September. Population of epilachna beelle showed significant positive correlation with averuge temperature, relative humidity and weekly rainfall. Duration of life cycle was shortest (26.71 days) in June-July and longest (33.52 days) in September-October, but heighest fecundity (272.32 eggs) was recorded during March-April. Life cycle was significantly and negatively correlated with temperature and relative humidity but fecundity was positively correlated with temperature and relative humidity. High temperature and humidity during July to September lowered down the duration of life cycle and increased fecundity leading into rapid multiplication of pest resulting higher population level and thereby crop loss during the period.