The black-headed caterpillar, Opisina arenosella Walker is an important defoliating pest of coconut, causing considerable damage to leaflets. The current investigation was commenced to document the occurrence of O. arenosella on coconut in Satara district of Maharashtra, India. During, 2025 field surveys were conducted in selected coconut-growing areas to assess the presence of the pest and its characteristic damage symptoms. Infested palms were identified based on the presence of larval feeding galleries, dried and discolored leaflets, and different developmental stages of the pest. The occurrence of O. arenosella in the surveyed areas indicates its establishment in the district and highlights the necessity of regular monitoring of coconut plantations. The findings emphasize the significance of early detection and implementation of practices under integrated pest management, particularly conservation and utilization of natural enemies, for sustainable suppression of this pest. The present study reveals practical evidence on the local occurrence of O. arenosella and can offer a baseline for further studies on its incidence, seasonal dynamics and management.