Population dynamics of major insect pests of brinjal crop in summer season

Abstract

Seasonal incidence of jassid, whitefly and shoot and fruit borer was studied on brinjal crop and found that the activity of both jassid and whitefly was initiated in the first week of April with mean density of 4.33 hoppers and 6.33 whiteflies per plant. It was associated with 35.94 °C and 20.78 °C maximum and minimum temperatures and maximum relative humidity around 75%. The peak activity of these insects was observed during first week of May when the day and night temperatures fluctuated between 25°C and 40 °C and relative humidity around 55%. The correlation studies between jassid and whitefly and different weather parameters revealed no significant effect of ambient weather on the population fluctuations of these insects. Shoot and fruit borer incidence was first observed on brinjal fruits during first week of April with peak activity of 66.66% in May first week when day and night temperatures varied from 20 °C to 40 °C and maximum relative humidity around 60%. Correlation studies between % fruit damage by fruit borer and ambient weather revealed a significantly negative relationship with minimum temperature and significantly positive relationship with maximum relative humidity.