Dogwood Twig Borer

Introduction

Dogwood twig borer (Oberea tripunctata; Figs. 1 & 2) is a small longhorn beetle that attacks the twigs of dogwood, elm, azalea, viburnum, poplar, willow, and many fruit trees. A native species, the dogwood twig borer is found throughout the eastern and central U.S.

Identification

Adult beetles are slender and cylindrical, measuring approximately 0.5 inches (1.3 cm) in length (Fig. 1). Adult coloration can vary widely. The antennae may be dark, or dark at the bases and more yellowish orange towards the tips (Fig. 2). The head, legs, and thorax are usually yellowish orange, and the underside tends to be darker in color (Fig. 2). There are three prominent black spots arranged in a triangle on the thorax (Fig. 1). There may be orange and black stripes on the wing covers, or the wing covers may be shaded to a dark grayish-brown or black.

Dogwood twig borer larvae are creamy yellow with a tan head capsule. The noticeably segmented body (Fig. 3) of mature larvae measures about 0.75-1” (2-2.5 cm) long.

Life History and Damage

In early summer, adult female dogwood twig borers girdle the tips of twigs and deposit eggs near the damaged areas. Eggs hatch and the young larvae bore into and down through the center of live green twigs. They create a characteristic series of closely spaced round holes in the twig bark, through which they push frass out of their galleries (Fig. 4).

Feeding damage by the larvae usually causes the twigs and small branches to wilt and die back (Fig. 5). Larvae periodically girdle twigs internally, causing the twigs to break off. Larvae plug these openings with frass and continue tunneling down the center of the green twig until they pupate. The larvae overwinter inside their galleries. In spring, some of the larvae pupate while others continue their development as larvae into the second year. Pupating larvae emerge as adults by mid-May or early June. There is one generation per year.

Management

Pruning infested twigs as soon as they are found and destroying them is an effective control measure.

Care should be taken to remove the larva or pupa at the base of each mined twig or branch.

If plants have been infested with dogwood borer in the previous year, spraying recommended insecticides on the plants before bud break may be helpful. Insecticide sprays will kill adult beetles as they girdle the twigs, as well as the newly hatched larvae boring into the twigs. Dogwood twig borer is a sporadic pest causing minor damage, and chemical treatment will not be needed every year. See the Virginia Pest Management Guide for Home Grounds and Animals (https://www.pubs.ext.vt.edu/456/456- 018/456-018.html) or Horticulture and Forest Crops (https://www.pubs.ext.vt.edu/456/456-017/456- 017.htmls.html) for specific insecticide recommendations depending on homeowner or commercial production use.

Note

The similarly named dogwood borer (Synanthedon scitula) is a moth and not a beetle. Unlike Oberea tripunctata, the dogwood borer moth is a significant pest of dogwood. Synanthedon scitula typically burrows into the lower trunk or base of a host tree, especially those with mechanical damage or burr knots. In contrast, Oberea tripunctata is limited to small twigs and branches in the canopy.

Revision

Theresa A. Dellinger, 2020 and September 8, 2025.