Wingspan 10 to 12 mm. The small white and dark blotched adult is quite distinctive.

Damp habitats such as river and canal banks and marshes.

Flies between May and August in one or two broods depending on latitude.

The larvae mine the stems of Reed Canary-grass and Common Reed; occasionally on other grasses. The pupa is anchored externally on the foodplant by a silken girdle.

Occurring widely in England as far as southern Scotland, less so in Wales and Ireland. In the Butterfly Conservation’s Microlepidoptera Report 2011 this species was classified as common.

Occasional in Leicestershire and Rutland. L&R Moth Group status = C (very scarce resident or rare migrant).