Last modified: April 23, 2019, 12:44 p.m.
After 2004 this species has been recorded from all Belgian provinces.
The white caterpillar has a dark-brown head.
This species builds a slender, brown, spatula case cut out of a leaf. In May, the fully grown case is about 13 mm long. The mouth angle is circa 15°.
See also bladmineerders.be.
The eggs are deposited on the underside of a leaf of the host plant.
Before wintertime, mostly in September or October, the larva makes two consecutive youth cases before wintering. It resumes feeding in May, making the final case –in which it also pupates– in June, preferably on a twig and less often on a leaf.
The adults fly in June and particularly in July.
This species occurs everywhere in places with Alnus trees.