Sawfly

Habitat:

Usually found in softwoods. In solid timber, in the sapwood or heartwood of external timbers, especially cladding or fencing. May occur in preservative treated timber, or durable wood such as western red cedar. Damage frequently happens on new sites where various foods, which are the food of the larvae, occur.

Damage characteristics:

Emergence holes/tunnels are very short (usually less than 10 mm) unbranched, circular, 2-3 mm diameter. They are usually at right angles to horizontal surfaces, but may also enter end grain where tunnels may be slightly longer (less than 30 mm). There is no bore dust.

Insect characteristics and location:

Adult: A winged fly-like insect, not often seen.

Larvae: Up to 10 mm long, curved, pale brown or (more often) green. Three pairs of legs, 7 pairs of fleshy stumps on rear half of body. Found in early summer to autumn on food plants and on and around infested wood.