Field efficacy of the parasitoid, Pediobius imbrues (Hymenoptera: Eulophidae) on coconut slug caterpillar, Macroplectra nararia Moore (Lepidoptera: Limacodidae)

Abstract

The coconut slug caterpillar, Macroplectra nararia is one of the major pests of coconut plantations in Andhra Pradesh with periodic out breaks especially under favorable weather conditions. Though many parasitoids were identified against this sporadic out break pest, none were found amenable for laboratory rearing. A new larval parasitoid, Pediobius imbrues (Hymenoptera: Eulophidae) with a natural parasitisation ranging from 2 -10 per cent under field conditions was identified in slug affected coconut gardens in March 2015. This parasitoid was also found amenable for lab rearing on Bracon hebetor probably being facultative hyper parasitoid. Field release studies of lab reared P. imbrues against slug caterpillar in the affected coconut gardens revealed that a maximum of 41.41 and 50.31 per cent parasitsm of slug caterpillar, respectively, in 2017 and 2018 within 30 days after release and this promising parasitism provides scope for large scale field releases during slug caterpillar out breaks in view of major economic losses caused by the pest.