Diversity of insect pests of castor, Ricinus communis L and their ecological interaction in south-west Haryana

Castor, Ricinus communis L provides important industrial oil which is completely biodegradable. The present investigations were undertaken to study the population dynamics of insect pests of castor in south-west Haryana and their interaction with the abiotic factors for development of effective pest management strategies and forecasting the outbreaks of pest population. The insect pests namely Acanthodelta janata, Euproctis lunata, Dichocrosis punctiferalis and Empoasca flavescens cause serious damage to castor crop in south-west Haryana. The maximum population of A janata was recorded in 37^th SW when temperature ranged between 22.5–36.8°C during 2012 and between 25.0–33.6°C during 2013. The castor semilooper, A janata exhibited significant and positive correlation with maximum (0.750 and 0.651) and minimum temperature (0.480 and 0.553). Castor hairy caterpillar, E lunata appeared on the crop in 35^th SW at population level of 1.5 larvae/plant at temperature range of 24.1–34.2°C and 2.5 larvae/plant at temperature range of 24.1–34.2°C in the first and second year. The leafhopper, E flavescens population had a significant positive correlation with the maximum temperature (0.524 and 0.440) and a significant negative correlation with the morning relative humidity (−0.872 and -0.584). The capsule borer, D punctiferalis infestation increased and gradually reached at peak level of 10.0 and 12.0 per cent at 40^th SW when maximum temperature was 35.7°C and 42.4°C in respective years. Thereafter declined trend was observed due to fall in temperature.