Last modified: Dec. 16, 2018, 9 a.m.
A fairly common species throughout Belgium.
The egg is deposited on the underside of a leaf.
The initial gallery is slender and usually contorted, killing the uneaten tissues which turns brown. (this may be absent in exceptional cases where the egg is laid well away from veins) Later the mine follows a tortuous course, except when following a vein. The green frass (in fresh mines) is laid in arches and extends almost from edge to edge.
See also bladmineerders.be
The adults fly in two generations; during May and June and again in August.
The monophagous larva makes a leafmine on Betula.