Background: The univoltine leaf beetle Chrysolinafastuosa (Scopoli, 1763) is native to in the Palearctic Region from eastern Siberia to western Europe.
New information: First North American records are presented for C.fastuosa (Scopoli, 1763) (Coleoptera, Chrysomelidae, Chrysomelinae), as confirmed by vouchered specimens from Canada: Nova Scotia. Additional citizen science records from USA: Vermont are also discussed. Diagnostic information is presented to distinguish C.fastuosa from other North American Chrysomelidae and a species distribution model to assess its potential spread in North America is presented. This insect is expected to cause some feeding damage to above-ground parts of ornamental and invasive Lamiaceae, especially species of Galeopsis L. The species distribution model and the range of its host plant Galeopsistetrahit, suggest the north-eastern US and south-eastern Canada, from the Atlantic coast to the west end of Lake Superior provide the most suitable conditions for this species. The United States of America and Canada are now known to be home to 70 or more species of adventive Chrysomelidae.
Keywords: adventive species; biological control; invasive alien species; weed biology.