Palaearctic flea beetle Phyllotreta ochripes (Curtis) (Coleoptera, Chrysomelidae, Galerucinae), herbivore of Alliaria petiolata (garlic mustard), new to North America.

Background: The univoltine leaf beetle Phyllotreta ochripes (Curtis, 1837b) is native to the Palaearctic Region from Japan to western Europe. This species was previously evaluated as a potential biological control agent against invasive populations of the woodland weed Alliaria petiolata (Bieb.) Cavara & Grande (Brassicaceae) in North America, but rejected because it could harm native and at-risk populations of Brassicaceae. New information: First North American records are presented for Phyllotreta ochripes (Curtis, 1837). Specimens were examined from the USA: Illinois, Maryland, Michigan, Ohio and Pennsylvania. Internet photographs of apparent additional individuals from USA: Indiana, Michigan, Minnesota, Ohio, Pennsylvania, Tennessee, Wisconsin and Canada: Ontario were also examined. DNA barcoding analysis showed high genetic variability and possible cryptic species within European populations of P. ochripes. Diagnostic information is presented to distinguish P. ochripes. from other North American Chrysomelidae and a species distribution model to assess its potential spread in North America is presented. Phyllotreta ochripes breeds on invasive garlic mustard, Alliaria petiolata (Bieb.) Cavara & Grande (Brassicaceae) and also non-native Rorippa amphibia (L.) Besser and other species of Brassicaceae. A species distribution model and the range of its host plant A. petiolata, indicates the most suitable conditions for this species are in humid areas of eastern North America. However, most of the known records of this species were discovered in areas projected to have low suitability. This is likely a consequence of sampling bias towards western Europe and away from the eastern Asian portion of its native range. The United States of America and Canada are now known to be home to 72 or more species of adventive Chrysomelidae. [ABSTRACT FROM AUTHOR]