Answer: Viburnum Leaf Beetle, Pyrrhalta viburni, is native to Europe and most likely came to North America on nursery plants in the early 1900?s. It was first found in 1947 in Ontario Canada and later discovered in New York State in 1996. Interestingly the beetle did not occur in very high numbers for many years; only in late 1970?s it became a viable pest problem. In the Eastern US, the beetle has spread to neighboring states, including Maine, New Hampshire, Vermont, New York and a small part of Pennsylvania and Ohio.
In 2001, British Columbian gardeners began to find Viburnum leaf beetles in southern Victoria Island and the Fraser Valley. It appears to be spreading rapidly southward. Our Washington State Department of Agriculture expected the eventual spread of Viburnum leaf beetle into Whatcom County, which recently happened.
So, to answer your question, the leaf beetle can be destructive, but not all viburnums are susceptible. You didn't mention which viburnum you're growing. The beetles appear to prefer some species and cultivars over others. New York State entomologists are developing a host preference list. Viburnum dentatum (arrowwood viburnums), V. opulus (European cranberrybush), V. opulus var. americana (American cranberrybush), V. rafinesquianum (Rafinesque Viburnum) and V. sargentii (Sargent Viburnum) are the most susceptible to infestations. A complete host list can be found at: http://www.hort.cornell.edu/vlb/suscept.html.
WSU does not have a specific pesticide recommendation as of yet. As we learn more about Viburnum leaf beetle, pesticide recommendations can be made. Entomologists at Cornell are currently researching ?softer? insecticides for managing this pest.
The leaf beetle is specific only to certain viburnums and will not spread to other landscape plants. If your new plant is not on the list of susceptible varieties, you can plant it with a clear conscience.
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