Dogwood Twig Borer

Coleoptera: Cerambycidae, Obrea tripunctata

Authors: Eric R. Day, Director, Insect Identification Laboratory, Virginia Tech

Publication Number 444-625, Revised 2003

Plants Attacked

Elm, dogwood, viburnum, and many fruit trees.

Description of Damage

The larvae tunnel in live twigs and feed down the center of the branch, making a long series of closely placed round holes for the exudation of frass. Periodically, the larvae cut off portions of the twig from within and continue to feed inside the twig on the green wood working their way down.

Identification

Larvae are about one to two inches long and white with a yellowish-brown head. Adults are cylindrical, with a black head, wing covers, and abdomen. The thorax is orange with three black dots. The dogwood twig borer, Obrea tripunctata, is in the order Coleoptera and family Cerambycidae.

Life History

Adult borers appear in early June. They girdle the tips of branches and deposit their eggs on the living twigs near the girdling. Eggs hatch and the larvae enter the twig and bore down the center. Damage usually causes death to branches and ruins the appearance of shrubs or trees. The larvae overwinter in the stems. In spring some of the larvae pupate while others continue to develop into the second year. The pupating larvae emerge by mid May or early June. There is one generation per year. Larvae or pupae overwinter.

Control

Pruning and burning infested twigs is an effective control measure. Spraying with recommended insecticides prior to budding will also control this borer.

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