Forest longhorn beetle

Habitat:

Imported and British-grown softwoods and hardwoods. They attack standing or felled trees, or semi-dried timber which has the bark still attached. Damaged timber may be incorporated into buildings. While some larvae may survive and emerge later as adults, they cannot reinfest dry timber without its bark.

Damage characteristics:

Emergence holes Large, oval. Typically 6-10 mm across at the widest point.

Tunnels Oval, 6-10 mm in diameter. In bark and also scoring the sapwood. Somme deep tunnels at right angles to grain penetrating into the sapwood. These may be sectioned during sawing and mistaken for emergence holes.

Bore dust Not present. Tunnels may be blocked with a small mass of coarse fibres.

Insect characteristics and location:

Adults Wide range of appearance and size, but common species are brown or black with distinctive long antennae arising from notch of kidney-shaped eyes. Occasionally found on or around wood in spring or emerging from recently-dried timber.

Larva Straight, white, long, markedly segmented. Head sunk in thorax, jaws dark brown. May be single dark eye spot either side of mouth. Legs absent or else three minute pairs. Found beneath bark or in tunnels in recently felled/converted timber. Occasionally found in timber that has been recently dried.