Last modified: March 20, 2021, 11:48 a.m.
A not so common species throughout Belgium.
The larva forms a silken case, white when juvenile, but a brown, tri-valved tubular silken case when full-grown. This case is at that moment about 5–6 mm long and the mouth angle is 0°–20°.
See also bladmineerders.be.
The eggs are oviposited on the flowers of the food plant. The larvae feed on the flowers and the seeds living inside a brown silken case. The caterpillars can easily be found on the florets of the hostplant from mid-August till well in October.
In general, the fully developed larvae leave the plant to hibernate. Pupation takes place inside the case on ground level or on the florets.
The adults are night-active from the evening till sunrise and come infrequently to light.
C. argentula flies in July and August in one generation.