Last modified: Oct. 9, 2019, 7:20 a.m.
A common and resident species throughout Belgium but the established populations are regularly supplemented with migrating specimens.
See also bladmineerders.be
The larvae live in a loose web on the underside of the leaves of Brassica or other species of Cruciferae. Pupation takes place in an open, net-like cocoon on the foodplant or amongst detritus on the ground. The pupa hibernates and the imagines come to light.
The adults have been observed in Belgium from early April till the end November. There are two or three generations per year that can hardly be distinguished from each other.