Chrysomelidae - Pyrrhalta viburni - Own work, CC BY-SA 3.0,
Viburnum Leaf Beetle (Pyrrhalta viburni) – Photo Hectonichus

The songĀ Here Comes Another One from Monty Python might apply well to invasive species. Another recent arrival to Ohio is the Viburnum Leaf Beetle (VLB) which occurs from northeast Ohio eastward through Pennsylvania, New York, New England, and eastern Canada although it has not yet reached central Ohio. The VLB is native to Europe and first appeared in Ontario in 1947. We do not know how it got to North America but it was more likely transported by human commerce than by the beetles’ flying here on their own.

The VLB feeds on several species of viburnum, wild or cultivated, native or exotic. They seem to prefer some varieties over others; arrowwood and European cranberry viburnum seem to be favorites. Most of the damage is done by the larvae eating the leaves in May and June. A large population can completely defoliate and kill the plants, but long before then the skeletonized leaves are obvious and unsightly. If you notice that sort of damage, you probably have VLB. Adult beetles are plain-looking and about 1/4 inch long. They also chew holes in leaves but overall their feeding does less damage than do the larvae.

Viburnum Leaf Beetle larva
Viburnum Leaf Beetle larva

Viburnums are popular ornamental plants and also are a component of natural deciduous forests. I have seen no reports of defoliation and death of native plants out in the woods but I do wonder about the possibility that defoliation may cause sufficient stress to allow other shrubs (like bush honeysuckle) to gain a competitive edge. More likely the VLB “problem” is going to belong to homeowners and landscapers. While the beetles are not yet in central Ohio, much of our wholesale nursery plant production is in the area east of Cleveland where VLB is established, and we expect that infested plants might eventually arrive from there. Also, the beetles can fly.

VLB is readily controlled with several commercially available insecticides but some of our readers may be reluctant to do that. Fall pruning can be helpful as the beetles lay their eggs on twigs.

Fortunately the beetles eat only viburnum, and they do not invade homes like some other insects do. Unless you grow viburnums, you might not see the VLB once it arrives in central Ohio. If you do see one (or more) I would be interested to hear about it.