Notes on the Biology and Release of Caloptilia sp. nr. schinella (Walsingham) (Lepidoptera: Gracilariidae), a Biological Control Moth for the Control of the Weed Firetree (Myrica faya Aiton) in Hawaii

摘要

In Hawaii, the weed Myrica faya Aiton has invaded many native ecosystems where it is rapidly replacing many native plant species. The moth Caloptilia sp. nr. schinella is a native of the Azores and Madeira Islands in the eastern Atlantic where its natural host is M. faya. This insect was released in Hawaii in 1991 as a potential biological control agent. Eggs are laid singly on the underside of young leaves and hatch in 7 days. The first instar larvae enter the leaf where they mine under the epidermis of the lower surface. The mines eventually coalesce into a blotch. Later instar larvae exit the blotches and externally roll the apical tip of the leaf into a cylinder that forms a distinctive feeding shelter. The last instar larvae leave their shelters and spin oval-shaped, flat cocoons in which they pupate. Development from egg to adult required approximately 2 months. Extensive feeding studies conducted in quarantine in Hawaii to determine this insect’s host range indicated that it can complete its development on only one additional plant, the very closely related M. cerifera L. The host test results were used in a petition submitted to the Hawaii Department of Agriculture requesting permission to release this moth as a biological control agent in Hawaii. The permit was granted in 1991. Between July 19 and October 29, 1991, 725 adults and/or pupae were released within the Volcanoes Golf Course subdivision located adjacent to the Hawaii Volcanoes National Park on the island of Hawaii. Post-release monitoring conducted in October 1992 indicated that establishment had occurred. By July 1994, the population had spread throughout the golf course subdivision and up to 5 km southward into Hawaii Volcanoes National Park.