Wingspan 12-16 mm.
Although quite variable in intensity, this species generally has a distinguishing pale square blotch on the dorsum visible at rest, often inwardly edged darker, and with a single dark spot beyond.
It can resemble E. immundana, which however usually shows a rather more triangular pale patch, and is generally darker overall.
The adults fly in April and May, usually around light woodland and is fairly common throughout the British Isles.
The larvae bore into a stem of birch (Betula) or alder (Alnus), and then feed within a folded leaf.