Last modified: April 12, 2021, 11:33 a.m.
A not so common species throughout Belgium, but mainly observed in the northern part of the country. Possibly overlooked, as on many locations where the host plant grows larvae could be found.
The larva makes a gallery of up to 25 cm in the pitch of the stem, preferably in larger, thicker stems. On the outside there is no indication of their presence. When cutting an infected stem open in the lower half, one can notice the gallery that had been cut across. The gallery and frass are even more visible when splitting the stem in 2.
Before pupation the larva makes an exit hole leaving a thin piece of round or oval brown bark. The pupa does not protrude the exit hole before emergence.
The species hibernates in the adult stage.
One generation a year: from late August, and after hibernation untill April.
Monophagous on Epilobium hirsutum.