Hymenopteran parasitoids of black-headed caterpillar Opisina arenosella Walker (Lepidoptera: Xyloryctidae) in South India

The coconut Black Headed Caterpillar (BHC), Opisina arenosella Walker (Lepidoptera: Xyloryctidae), poses a significant threat to coconut plantations in South India. The present study investigates the diversity and prevalence of hymenopteran parasitoids associated with O. arenosella. BHC larvae and pupae were collected from 15 locations spread across 9 districts of Tamil Nadu. Life stages of BHC were reared to observe the emergence of parasitoids. A total of six parasitoids viz., Antrocephalus hakonensis (Ashmead), Brachymeria nephantidis Gahan, Kriechbaumerella sp. (Family: Chalcididae), Apanteles sp. (Family: Braconidae), Goniozus nephantidis Muesebeck (Family: Bethylidae) and Xanthopimpla punctata Fabricius (Family: Ichneumonidae) were found to be associated with larvae and pupae of BHC. This study provides the first documented evidence of Kriechbaumerella sp. parasitizing BHC pupae. The level of natural parasitisation by various parasitoid species varied across different sampling locations. Highest natural parasitisation (31.64 %) of BHC was noticed in Tiruppur district. Field surveys and laboratory rearing of collected specimens highlight the potential of these parasitoids for biological control, contributing valuable data towards integrated pest management strategies. Further research into the life cycles, host specificity and ecological interactions of these parasitoids is recommended to enhance their utilization in sustainable agriculture practices.