Pine Sawyers
Contact: Eric Day, Manager, Insect Identification Laboratory
ENTOMOLOGY PUBLICATION 444-216, August 1996
Pine Sawyers
Coleoptera: Cerambycidae, Monochamus sp.
Plants attacked
Pine, spruce, and balsam fir.
Description of damage
They are secondary infesters whose main
damage is disfiguring wood by larval boring and tunneling in
felled trees and usable trees which are weakened or dying from
other causes. Plant parts attacked trunk. Damaging stage -
larvae.
Identification
The adults are large cylindrical beetles, black,
brownish-black, or reddish brown, mottled with whitish or grayish
pubescence. The thorax bears a prominent spine on each side.
The larvae are elongate, cylindrical, and have large gnawing
mandibles. The larvae are legless.
LIFE HISTORY
Adult appearance coincides with the pollen release
by the host plants. Shortly thereafter they begin attacking
killed and felled trees, gnawing pits through the bark, and
inserting from 1 to several eggs in each pit. Upon hatching, the
larvae bore beneath the bark and mature between 40-60 days. At
this time the larvae enter the wood and make a deep U-shaped cell
through the sap and heartwood. The entrance is plugged with
frass, and the opposite end enlarged into a pupal cell. The
larvae pupates the following spring or early summer and the adult
emerges the same summer.
Control
Sanitation and prompt actions are the best controls
against these borers. Felled timber should be removed from the
woods as soon as possible. Secondly, the bark should be removed
from the logs to prevent infestation. Thirdly, logs may be
sprayed thoroughly if storing is required.
Remarks
Adults are attracted to the smell of various materials
with resin bases; turpentine, paints, etc., and are occasionally
thought to be emerging from homes.