According to Cornell University entomologists, the viburnum leaf beetle, Pyrrhalta viburni, recently introduced into the U.S. from Europe (by way of Canada), has the potential to become a widespread and significant pest. The beetle first appeared in 1996 in New York State and has since turned up in Maine, Pennsylvania, Vermont, and Ohio. It feeds exclusively and voraciously—in both its larval and adult stages—on viburnums. Susceptible plants typically die after being attacked for two or three years.

The beetles lay eggs in tiny but visible black-brown rows on young viburnum branches late in the growing season. Greenish-yellow larvae hatch early the following spring and grow up to 1/2-inch long. They are able to "skeletonize" viburnum leaves in a matter of days. In early June, the larvae fall to the ground and pupate. Adult beetles emerge by early July. They are roughly 1/4-inch long and brown in color.

Cornell has set up a web page called Viburnum Leaf Beetle Citizen Science to collect and disseminate information about the new pest. It features color photographs of the beetle in all its stages, as well as distribution maps. It also features pest-management instructions for the homeowner, including tips on physical (removal of egg-infested twigs), biological, and chemical control, and advice on planting bug-resistant species and varieties—and avoiding susceptible ones.

Susceptible Species

Field observations and Cornell laboratory studies have indicated that the following viburnum species are susceptible to beetle damage:

Resistant Species and Varieties

The Cornell researchers have found that viburnum species and varieties with thick, hairy leaves are showing resistance to the beetle. They list the following plants as highly resistant to beetle damage:

Related Links

For more information on the viburnum leaf beetle, check out these links: