OCCURRENCE, DAMAGE, COLOUR MORPHISM AND NATURAL ENEMIES OF MONOLEPTA LONGITARSUS JACOBY (COLEOPTERA: CHRYSOMELLIDAE), A DEFOLIATING PEST OF CASHEW

Abstract

The present study aimed at investigating the occurrence, damage pattern and natural enemies of a chrysomelid beetle Monolepta longitarsus Jacoby (Chrysomelidae: Coleoptera). Occurrence of the beetle was noticed in cashew plantations at Puttur and Shantigodu, Dakshina Kannada of Karnataka, India during 2012 and 2013. These beetles appeared immediately in large numbers after south-west monsoon showers (June) and infestation was continued on cashew, up to August. Dispersal of this pest did not follow a consistent pattern. Beetles in groups of 60-75 were capable of causing complete drying of cashew shoots within 2-3 days and thus the damage spread was fast. Four different colour morphs of beetles were noticed, in which, reddish orange colour morphs were dominant (> 60 %) throughout the observation period followed by black shouldered red and random mating was observed between all four colour morphs. A few species of reduviids and praying mantises were recorded as predators and Beauveria bassiana as entomopathogenic fungus of these beetles.