The midge Eriophyes arianus causes galls to form on the leaves of Sorbus aria.  The galls take the form of slightly rounded pustules raised on both surfaces of the leaf, up to 2 mm across, sometimes coalescing, and with the opening on either the upper or lower leaf surface. The galls are light green or yellowish at first becoming brown later.  It should be added that that taxonomy of the gall mites that cause this type of galls on the genus Sorbus is not yet fully stabilised.

Gall  

Good photographs required of upper and lower leaf surfaces showing the galls, and of the host plant. Please state the host species when submitting your record.

Galls may be found wherever the host species occurs.

Galls may be found when the host species is in leaf.

Status in Britain is difficult to determine due to lack of records.

Status in Leicestershire and Rutland not known.