House longhorn beetle

Large woodworm
Hylotrupes bajulus

Dangerous, globally widespread conifer pest that can vary in color. While the adults do not feed, the danger comes from the larvae. These feed in the sapwood of construction timber: load-bearing or non-load-bearing construction parts in buildings (roof trusses!) as well as on outdoor timber. The larva leaves only a paper-thin outer layer intact, which makes it difficult to recognize an acute attack. Only oval flight holes of the young beetles are visible, some with serrated edges (Ø 3-4 x 5-10 mm). Larval galleries are oval in cross-section, filled with fine, powdery, loose bore meal mixed with cylindrical excrement particles, the walls of the galleries show the typical larval “ripple mark structure”. The female lays approx. 6-8 clutches with approx. 50 eggs in cracks or crevices (including those resulting from carpentry joints) as deep as possible in the wood with the aid of a flexible laying tube.