Coconut Black-Headed Caterpillar, Opisina arenosella Walker(Lepidoptera: Oecophoridae): Host Plant, Biologyand its Natural Enemies

Abstract

The coconut black-headed caterpillar (BHC), Opisina arenosella Walker has been an exotic invasive insect pest of coconut damaging of Thai coconut industry in recent years. For host plant study, the coconut leaves were suitable for BHC
larvae by giving the highest net reproductive rate (Ro) of 66.31 times and followed by Bismarck palm, banana and oil palm, respectively. The cohort generation time (Tc) of all tested leaves was ranged between 71.16-74.69 days. The efficiency of parasitism of the endemic parasitoid (Bracon hebetor Say) and exotic parasitoid (Goniozus nephantidis (Muesebeck)) by comparing the percentage of parasitized larvae and the number of emerged adults both in single and combined two species were investigated. The parasitism rate was tested at 1, 3 and 5 larvae under periods of parasitize at 1, 3 and 5 days, respectively. The single parasitized of B. hebetor showed the highest parasitized at 96.85%. The average number of emerged adult of B.hebetor parasitized 1 BHC larvae at periods of parasitize 1 days showed the highest number of emerged adult 13.25 individuals and the sex ratio of female to male was 1.30. The endemic parasitoid, B. hebetor, gave higher efficiency of parasitized to BHC than exotic one, G. nephantidis.