Last modified: Nov. 10, 2019, 6:33 p.m.
A very common species throughout Belgium, although often confused with other greyish species!
The strongly curved youth case is a “composite leaf case”, the adult case is a “tubular leaf case”. The adult case is trivalved, about 7 mm in length, the mouth angle is 30°. The case is straw coloured and almost always has a toothed dorsal keel (remnant of the margin of the leaf from which the case was cut).
See also bladmineerders.be.
The egg is deposited at the underside of the leaf.
The larvae start feeding in September and continue till the end of October. They hibernate in their case, and resume feeding in April. After some weeks they exchange their youth case for the definite one, and continue feeding till early June.
The adults fly from late May till the end of July.