Wingspan 21-30 mm.
All four of the British species of Dioryctria can be difficult to separate on external appearance, although there are some guidelines which may help.
D. simplicella tends to have less contrast on the forewing markings than the other three species, and is usually smaller than D. abietella, which it is perhaps most often confused with.
It occurs throughout England and Scotland, but is commonest in East Anglia. It inhabits pine plantations and the larvae feed on the shoots of Scots pine (Pinus sylvestris) and related species.
The normal flight period is between July and September.