Ramie Moth, Arcte coerula (Lepidoptera: Noctuidae): A New Invasive Pest in Hawaii on Endemic Plants

Abstract

In November 2018, the ramie moth, Arcte coerula (Guenée, 1852) (Lepidoptera: Noctuidae) was found defoliating māmaki trees, Pipturus albidus (Hook. & Arnott.) A. Gray (Urticaceae) on Maui. This was the first detection of the ramie moth in Hawaii and the United States. As of November 2020, this new pest has spread to Hawaii island. Māmaki has cultural importance to the islands as a medicinal plant in lāʻau lapaʻau, a traditional native Hawaiian healing methodology utilizing plants, ecological importance as an essential food source for endemic insects including the state insect, and economic importance as an emerging tea crop. Field and laboratory observations suggest that high populations of A. coerula could potentially devastate these trees. Here we review the literature regarding this insect and assess the threat A. coerula poses to Hawaii. The biology and life cycle of A. coerula feeding on māmaki in Hawaii is described.