Last modified: Sept. 16, 2019, 12:46 p.m.
A rather common species throughout Belgium.
At first just a small silvery line with a central brown line, on top of a leaf vein. Later a white, whitish grey or silvery, semi-circular or oval, tentiform mine on the upperside of a leaf, most of the time on the central vein or a strongly developed side vein. At the beginning without any longitudinal folds, but later with quite some folds making the leaf to curl upwards. The frass is scattered all over the leaf, contrary to the situation in *Phyllonorycter leucographella", that occurs partly on the same host plants, where the frass is concentrated.
This species has a very complicated mining behaviour. In the first tentiform, epidermal mine, a second, smaller mine is constructed in the pallisade parenchyma. After feeding for a while in this second mine, the caterpillar consumes the roof of that small mine and just a central, black patch remains.
See also gracillariidae.net and bladmineerders.be.
It pupates inside the mine and the pupa hibernates. The adults are mainly active at dusk and come to light.
The adults fly in two generations a year: from late April till June, and again in August.