Viburnum leaf beetles now in Minnesota

The Minnesota Department of Agriculture (MDA) announced yesterday (July 25) that the viburnum leaf beetle (VLB), Pyrrhalta viburni, has been confirmed in Minnesota in Eden Prairie. VLB is an invasive insect species from Europe and is now found in scattered infestations throughout northeastern U.S. as well as Wisconsin. 

VLB love viburnum shrubs, especially arrowwood viburnum, American high-bush cranberry, and European high-bush-cranberry. Larvae hatch in early spring and feed on the leaves until early summer.  They eventually skeletonize them, i.e. feeding between veins. This damage is similar to the feeding by Japanese beetles. The larvae are yellow to brown in color with many black spots. They grow to almost ½ inch long.

Viburnum leaf beetle larvae and damage.  Photo: Milan  Zubrik, Forest Research Institute - Slovakia, Bugwood.org

Adults are brown and nondescript and are only about ¼ inch long. They are active during the summer and into the fall when they chew oval holes in the leaves, typically not crossing the veins (in some cases they might cross the veins). Females lay eggs in the twigs in small cavities, which, while small, can be seen, especially during winter when the leave are gone. 

Viburnum leaf beetle adults.  Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Adults and larvae can potentially defoliate shrubs; repeated defoliation can weaken and possibly kill viburnum.  MDA is very interested to learn where VLB is in Minnesota.

Viburnum leaf beetle egg laying sites:   Photo: Paul Weston, Cornell University

They encourage residents to report suspected VLB by one of several methods

• Send in photos, location, and other info via Arrest the Pest (arrest.the.pest@state.mn.us or 1-888-545-6684); 
• Report finds to EddMaps online; or,
• Use the Great Lakes Early Detection Network (GLEDN) app for Android and IOS operating systems.

For more information see the MDA news release, Invasive insect viburnum leaf beetle discovered for the first time in Minnesota and Viburnum leaf beetle by the University of Wisconsin.

Jeff Hahn, Extension Entomologist