Viburnum leaf
beetle home
Back to How to identify viburnum leaf beetles
Video:
Adult laying eggs
[Video by Jame Reilly]
Larva emerging
[Video by D. Swaciak]
Logo images by Kent Loeffler, Paul Weston & Craig Cramer
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When to look: July to May
What to look for: Rows of small bumps, 1 to 2 mm in diameter (between the size of a pin head and match head). The bumps are brownish-black contrasting sharply with greenish to brownish bark.
These bumps are not the eggs themselves. Adult females excavate small cavities in the twigs, lay up to eight eggs inside, then seal the egg-laying site with a cap made of chewed bark and excrement held together by a special cement that they make.
Where to look: Along the underside of young branches, usually the current season's growth.
In late summer and fall, you can often find them on stems near leaves where adults have been feeding. (See below.)
Egg-laying sites are often easier to spot in winter when there are no leaves on the viburnums.
Larger image. Photo by Mary Woodson
Heavily infested viburnum twigs are easy to spot in fall and winter when the leaves have fallen off the shrubs.
Larger image. Photo by Craig Cramer
These viburnum twigs, collected in early fall, show the characteristic row of capped egg cavities. They also show a range of cap size from nearly flat to highly rounded.
Larger image. Photo by Craig Cramer
Close up of egg caps on fall-collected twigs.
Larger image. Photo by Kent Loeffler
In early spring, as the new leaves emerge and the larvae hatch out of the eggs, you can sometimes spot the old egg-laying sites on dead tips of twigs. The larvae move down from the egg sites to begin feeding on the new leaves.
Photo by Paul Weston
In summer, newly created egg-laying sites contrast sharply with green stems on this cranberrybush (Viburnum opulus).
Larger image. Photo by Paul Weston
Egg-laying sites adjacent to leaves damaged by feeding adults.
Larger image. Photo by Paul Weston
Egg-laying site in winter.
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