Dogwood Twig Borer
Oberea tripunctata (Swederus), Cerambycidae, COLEOPTERA


DESCRIPTION

Adult -The adult is a slender beetle measuring 10 to 15 mm long and 3 mm wide. The head is dark to almost black. A triangle of three black spots is visible on the top of the thorax. The wing covers are yellow tan, with a narrow, black line on the inner edge and a broader, darker line on the lateral margin.

Larva-When fully grown, the larva is yellowish, legless, and about 19 mm long.


BIOLOGY

Distribution -Wherever flowering dogwoods are grown, the dogwood twig borer is a threat.

Host Plants -Elm, viburnum, azalea, and many fruit trees may be attacked by the dogwood twig borer, though its principal host is the flowering dogwood.

Damage -Wilting leaves on individual twigs or drooping girdled tips usually indicate infestation by this borer.

Life History -The dogwood twig borer is the larval stage of a small, long-horned beetle. It is also known as the elm twig girdler. Seldom appearing in large numbers, adults emerge in early summer. After girdling the tip of a twig, the female deposits her eggs singly in its bark crevices. When an egg hatches, the larva tunnels along the center of the twig, making a series of closely placed holes to remove the boring dust. Portions of the hollowed branch may be internally separated from the plant as the larva moves into the green wood. The winter is usually passed in the pupal stage inside the tunnel.


CONTROL

After wilting occurs in the spring, the twig should be clipped off several inches below the girdled or infested portion and destroyed.

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