Viburnum Leaf Beetle, Pyrrhalta viburni (Paykull) (Coleoptera: Chrysomelidae): Dispersal Pattern of a Palearctic Landscape Pest in New York and its Distribution Status in the Northeastern U.S. and Eastern Canada

Pyrrhalta viburni, a chrysomelid leaf beetle native to Eurasia, was first detected in central New York in 1996, and since has been spreading throughout the state. Distribution records are given and mapped for this Viburnum-feeding specialist in New York, Pennsylvania, Ohio, and Vermont. By summer of 2002, P. viburni had been recorded from 33 counties in New York, and its subsequent spread throughout a larger portion of the U.S. can be anticipated. In addition to feeding on several species of cultivated viburnums, the beetle also thrives on the native Viburnum dentatum var. lucidum (arrow-wood), a widely occurring understory shrub in northeastern North America. The dispersal of P. viburni in New York has largely followed the distribution of its host plants, which leads us to predict that future spread will proceed most quickly through habitats contiguous with the current distribution of the pest and containing denser stands of V. dentatum var. lucidum or other native and cultivated viburnums that are suitable hosts for P. viburni. We also summarize the current distribution of P. viburni in neighboring states of the northeastern U.S. and in provinces of eastern Canada, based on personal communications with entomologists most acquainted with this ornamental and nursery pest.