Viburnum Leaf Beetle

Pyrrhalta viburni

Key Features


  • Holes in leaves
  • Egg bumps laid on stems.
  • Golden brown beetles
Total defoliation by viburnum leaf beetle. Photo c.o. Bryan Overstreet Purdue Extension
Adult feeding by viburnum leaf beetle
Closeup of larva. Photo c.o. Bryan Overstreet Purdue Extension

Symptoms


Beetles defoliate certain species of viburnum. Wintering as eggs on stems, larvae hatch in May to feed on leaves. Young larvae chew small holes and skeletonize leaves. Golden brown brown beetles appear in mid July and will feed on leaves until frost.

Larvae and feeding by viburnum leaf beetle. Photo by M. Zubrik, Forest Research Institute, Slovakia, Bugwood.org
Viburnum leaf beetle eggs on stems. Photo by P. Weston, Cornell University, Bugwood.org

Biology


Beetles winter as eggs on stems. Eggs hatch in May into green larvae that skeletonize leaves. In late June and early July larvae will drop to the ground and pupate. About 10 days later in mid July adults will emerge and feed on leaves. Adults continue to feed on leaves for the remainder of the summer until frost and will lay eggs on twigs. Beetles are common in the North Eastern states, but rare in IL, MI, OH.

Adult viburnum leaf beetle. Photo by W. Cranshaw, Colorado State University, Bugwood.org

Management Recommendations


In dormant season remove stems with obvious egg masses. In March prior to bud break, apply horticulture oil at the dormant rate (4%) to kill eggs glued to stems. When larvae are present on leaves 2% applications of insecticidal soap or spinosad will kill larvae. These two methods are preferred because they allow beneficial insects to kill much of the remaining populations. Other products can be used to kill adults and larvae but care should be taken to avoid applying product when shrubs are in flower and bees and other pollinators are foraging. Plant resistant species (not Arrowwood and Cranberry bush viburnum) in areas where Viburnum leaf beetles are a problem. If you find this pest in Indiana report this pest to 1-866-NO-EXOTIC.

Effective Pesticides


Active Ingredients include: Bifenthrin, Horticultural oil (Paraffinic or superior oil) , Insecticidal soap (Potassium salt of fatty acid), Lambda- cyhalothrin, Spinosad

landscape report
Purdue Landscape Report
PPDL
Plant & Pest Diagnostic Laboratory