Typical damage is shown in photo.
This sawfly is one of the most destructive of the native sawflies, especially to young pines. The life history of the red-headed pine sawfly is complicated, but it may have one to two generations each year. Broods of larvae may be found feeding from May until late fall. Adults lay their eggs in slits in the pine needles and the larvae, upon emergence, become full grown in 25-31 days.