The gall midge Contarinia petioli has a larva that causes a gall to form on the petiole (stalk) of Aspen leaves. The gall is seen more often than the midge. The gall is globular or pear shaped, 3 to 8 mm across and sometimes reddens.

It can occasionally occur in the stem at the junction with a petiole, and also it seems where the petiole enters the leaf.

The moth Ectoedemia argyropeza causes small elongated galls on Aspen petioles

Gall  Adult

On Aspen.

The gall can be seen in late summer or early autumn.

The galls contain one, or a few chambers, each with one orange larva; a circular opening develops in mature gall through which larva leave.

Records are widely scattered in Britain but the species is little recorded.

Very few records for Leicestershire and Rutland, but this may be purely due to under recording.