Natural enemies of oil palm defoliators and their impact on pest population

Oil palm, Elaeis guineensis Jacq. is an important oil crop introduced to meet the vegetable oil needs of the country. Among the lepidopteran pests that cause defoliation of oil palm, psychid, Metisa plana, leaf web worm, Acria sp. and slug caterpillar, Darna catenatus were observed as major ones. Severe infestation of leaf eating caterpillars in Krishna district of Andhra Pradesh caused 29% yield reduction during first year and 31% in second year after the pest attack. Mortality of the pests due to their natural enemies was recorded at moderate level in all the gardens of Krishna, West and East Godavari districts of Andhra Pradesh. Parasitoids were recorded as major and important ones on both psychid and leaf web worm while virus was predominant on slug caterpillar. Goriphous bunoh, Brachymeria spp. and Dolichogenidea metesae are the main parasitoids recorded on psychids causing 39.2% parasitism with a range of 15.83 to 65.23%. The former is a pupal parasitoid while the later were recorded on larval stages. Elasmus brevicornis, Apanteles hyposidrae and Brachymeria spp. were recorded on leaf web worm causing moderate mortality in late stages of the pest. NPV and Granulosis virus were however recorded as the possible bioagents to check the slug caterpillar.