Last modified: Feb. 28, 2021, 12:02 p.m.
A fairly common species throughout Belgium, especially in the northern part of the country.
Head brown; forewing ochreous brown, white pattern consisting of two transverse bands, a very short basal streak; three costal and two dorsal striae, the first ones often merged in the middle of the wing and the last ones sometimes very small; a patch of dark brown scales in the apical area.
A rather small, at first semi-circular or oval, tentiform mine on the upperside of a leaf; later growing into a more elongated mine. The mine does not contort the leaf much; it is yellowish green and has one longitudinal fold in the centre. The mine is often situated on top of a secondary vein. The frass is concentrated in a corner of the mine.
See also gracillariidae.net and bladmineerders.be.
The last instar of the summer generation makes a very flimsy spinning, that of the autumn generation constructs a tough, white cocoon.
The species hibernates in the pupal stage, between leaf litter on the ground. After emergence of the adult, the pupal skin protrudes through the mine.
Two generation a year: May and August.
The larva lives mainly on Alnus glutinosa, but it has also been recorded from Alnus incana and Alnus cordata.