Last modified: April 20, 2021, 8:26 a.m.
A fairly common species in Belgium, its presence mainly recorded from leaf mines, not so often seen in the adult stage.
At first a very small, inconspicuous gallery, mostly but not exclusively at the upperside of the leaf. Later instars make a semicircular or oval blotch mine, sometimes partly or completely covering this gallery. The blotch is greyish white at the beginning but soon turns into orange brown, except when it is an underside mine where the original colour is kept.
See also gracillariidae.net and bladmineerders.be.
Only the first instar keeps its frass in the narrow gallery, but the following instars eject the frass from the blotch mine. The free living caterpillar turns a leave edge downwards and spins it into a fold under which the larvae feeds. Usually, two such folds are made during the entire life cycle.
Pupation in a folded leaf-edge among leaf litter.
Hibernation in the pupal stage.
Adults hide among the foliage during day-time. They are not very active but come to light.
The adults fly in one generation a year: from the end of April till the end of June.
The caterpillars feed mainly on Malus, both wild species and many cultivars. Mines have also occasionally been recorded from other Rosaceae species, like: Pyrus, Crataegus and Cotoneaster.
Old orchards and gardens with apple trees.