The larvae of the midge Rhopalomyia foliorum cause small oval galls, about 2 mm long, first on the stem or leaf of Artemisia (Mugwort) and then generally at the upperside of a thick vein. Eventually the plant may become distorted with leaves bunching. Larva is orange.

Gall Adult

Please provide a photograph showing the gall.  Please also include a photograph of the larva and state the host plant.

The galls may be found where Mugwort is present.

Gall: When Mugwort is in leaf.

Several generations; the larvae of the summer generation pupate in the galls, the winter generation hibernates in the soil, then pupates.

True status in Britain is difficult to determine due to lack of records.

Status in Leicestershire and Rutland not known.