NC State Extension Publications

Description and Biology

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Dogwood clubgall midges, Resseliella clavula, are tiny flies that emerge in spring as the new leaf growth resumes on dogwoods. The delicate adult is about 1/16 inch long. The abdomen is bright orange; the thorax is yellow orange or duller. The wings are mottled with varying patches of black and yellow hairs, which in some specimens resemble irregular, black and yellow bands. The male's antennae are about the same length as the body, the joints appearing beadlike. The female's antennae are shorter and less conspicuously adorned. The larva is an orange-colored maggot. Females lay eggs in newly developing buds, and as the maggots hatch and feed, their saliva causes a swollen, tough gall to form around them. The maggots develop inside the gall until late summer. In autum, maggots emerge from the galls by chewing small, round holes through the sides. They drop to the soil under the dogwood trees, where they overwinter probably in a tiny silk cocoon. Pupation occurs the following spring. In late spring, adults emerge and lay their eggs among the minute terminal leaves. Usually the eggs are laid on the most vigorous twigs where the nodes are close together in the developing bud. Upon hatching, the maggots work their way into the interior of the leaf base or into petioles at the junction of the apical pair or two pairs of minute terminal leaves. Occasionally, entrance to the midrib may be through adjacent leaf tissue. Feeding causes the formation of an elongate gall, where the maggots live in a central cavity. From 1 to 39 maggots may be found per gall.

Dogwood clubgalls

Dogwood clubgalls are unsightly and cause twig dieback.

clubgall midge pupa

Here a dogwood clubgall midge seems to have pupated in the gall rather than in soil.

Host Plant

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Dogwood seems to be the only host for the dogwood clubgall midge. The dogwood clubgall midge causes club- or spindle-shaped tubular swellings (galls) from 1/2 to 1 inch long, which form at the tips or along the stems of dogwood twigs. The twig beyond the gall may die. From 30 to 120 galls per tree have been reported. Some of the twigs may die above the swollen part, and the tree may be deformed if the infestation is heavy.

Residential Recommendations

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Once the gall has formed, it is probably not possible to control the midge maggots inside with pesticides. Some sort of contact pesticide could be applied just as the leaf buds are breaking to give adequate control of dogwood clubgall midges. Once the galls have formed, pruning is probably the only management choice.

Other Resources

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For assistance with a specific problem, contact your local Cooperative Extension Center.

This Factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology & Plant Pathology

Publication date: Feb. 14, 2019
Revised: Sept. 13, 2019

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