Last modified: April 23, 2019, 12:44 p.m.
Had been known from various localities in Belgium, especially from the Sonian Forest and the coastal area, then the species disappeared from the country for about 50 years, but it is now well present in several provinces, though not everywhere, and never common.
Head ochreous; forewing ground colour golden ochreous, white pattern consisting of a thin, long basal line, reaching the middle of the wing and finely edged with brown scales; four costal and four dorsal striae; the first dorsal stria just a match of some whitish scales, the second one much longer than the other ones and curved towards the apex; apical area shining purplish in fresh specimens; a small blackish dot in the apical area.
At first a rather small (max. 14 mm), semi-circular or oval tentiform mine on the underside of a leaf, between two secondary veins, preferably situated near the nasis of the leaf. Later, the mine becomes longer; it has one longitudinal fold in the middle. The dark frass is concentrated in a longitudinal U-form inside the mine.
See also gracillariidae.net and bladmineerders.be.
The species hibernates in the pupal stage. However, in xerothermic regions, the larva of a third generation seems to hibernate in evergreen oak species, like Quercus ilex. This has thus far (2018) not been observed in Belgium.
Two generations a year: May and August.
The species has a preference for Quercus species, especially Q. robur, Q. petraea and Q. ilex, but it can develop also on a variety of other trees, like Carpinus betulus, Castanea sativa, Fagus sylvatica, and even Tilia cordata.