The Viburnum Leaf Beetle & The Risks They Pose

With spring on the horizon and summer shortly after, it is important to prepare for those insects that can affect your shrub’s trees more than others. Viburnum beetle (VLB) larvae will emerge and feed on the Viburnum leaves in the late spring into early summer. The larvae will then move to the soil to pupate. The adult leaf beetle will emerge in mid-summer. The adult stage of the leaf beetle will again feed on the leaves of the host plant. The female viburnum leaf beetle lays eggs on Viburnum stems/twigs from the beginning of summer, all the way to the first frost of winter. The threat of the viburnum beetle can last a significantly long time.

Characteristics of the Viburnum Beetle

The adult viburnum leaf beetle is a yellowish-brown color and is approximately ¼ of an inch long. The young worm-like stage, or larvae, of the viburnum leaf beetle, can grow up to ⅓ of an inch. During this stage, the viburnum leaf beetle’s color is greenish-yellow with the potential of having black spots or lines across the back of their bodies.

What is the threat of the leaf beetle?

Viburnums, such as the Arrowwood Viburnum are known for their spring flowers, dark green leaves in summer, and glossy reddish-purple fall color. During the spring, VLB larvae begin to chew holes through the viburnum leaves, resulting in a lace-like pattern. This lace-like pattern can be damaging due to the larva choosing to feed in small groups, resulting in larger areas of damage.

When feeding becomes heavy enough, the damage will cause severe decline. If affected shrubs are defoliated, they will become stressed. If repeated, defoliation can cause the death of affected plants.

What is the life cycle of a viburnum leaf beetle’s life cycle?

When it comes to the life cycle of the viburnum leaf beetle, females can deposit up to 500 eggs at a time. In late summer and early fall, these eggs are laid on viburnum twigs and small branches. The adults cover the eggs with tiny pieces of chewed wood, in hopes of protecting them. The eggs need a chilling period of approximately 5 months over the winter. Then, these eggs will hatch into larvae in early spring. From there, these larvae go through three stages of development until the mature larvae enter the soil to pupate. The pupal stage lasts for about a week and a half where they emerge as adults in mid-summer and repeat the cycle. There is one complete life cycle per year.

How do I rid my yard of leaf beetles?

When it comes to the protection of your property, first think about calling a Certified Arborist to assess the situation occurring on your property. A quick fix can be to identify where the viburnum leaf beetle eggs have been laid and apply treatments appropriate for the time frame. The use of horticultural oil or insecticides can combat the excessive production of more VLB.

As always, if you find yourself worried about your trees and shrubs, contact a Certified Arborist for help. We at Wachtel Tree Science value our clients and those who are concerned about their landscape.