Last modified: Nov. 18, 2023, 2:50 p.m.
A fairly common species throughout Belgium, more distributed in the northern part.
Wingspan: 12–14 mm.
C. alnifoliae is ochreous to light brown with a grey tinge.
The antennae are ringed alternately white and brown to 5/6 of the top while the remaining part is uniformly white.
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 . 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.