The wingspan is 15–19 mm.
Adults are on wing from July to August.

The larvae feed on the Lactuca serriola, Lactuca vireola and other Lactuca species.
Larvae are considered a pest on cultivated lettuce.
Young larvae live in the flowerheads, producing very little webbing and sometimes feeding partially exposed.
Later they burrow into the developing seedheads and feed on the ovaries.
The wingspan is 15–19 mm. Adults are on wing from July to August.
The larvae feed on the Lactuca serriola, Lactuca vireola and other Lactuca species. Larvae are considered a pest on cultivated lettuce. Young larvae live in the flowerheads, producing very little webbing and sometimes feeding partially exposed. Later they burrow into the developing seedheads and feed on the ovaries.
Eucosma conterminana