Last modified: Aug. 21, 2020, 6:29 p.m.
A fairly common species throughout Belgium.
Hibernates as a larva inside a stem of the food plant. In spring it bores downwards in the centre of the stem, leaving loose frass in the upper part. When nearly full grown, large amounts of wet green frass are deposited in the lower part of the stem. Infected stems are recognizable by the wilted (yellowish) top leaves. Infested stems often stay smaller compared to healthy ones. The full grown larva leaves the stem trough a round hole, clearly visible from outside. It pupates in a cocoon on the ground or in leaf litter. The adults come to light and sugar.
The adults fly from early June till mid August in one generation.