Fir Engraver
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Hosts
Primarily grand fir. Occasionally it will infest Douglas-fir, subalpine fir, western hemlock, and spruce.
Distribution
Throughout host range.
Damage
Adults and larvae feed in phloem layer of inner bark. Frequently only "patch" attacks are made on bole. Often trees are top killed. Trees can be killed if attacked by enough beetles (fig. 53). Trees of any size may be attacked.
Identification
The gallery pattern of the fir engraver is unique (fig. 54). Unlike most other bark beetles, the female constructs a horizontal egg gallery, perpendicular to the grain of the wood. Red-brown boring dust marks the sites of new attacks during summer months. Eggs are deposited on each side of the gallery and larvae tunnel at right angles to the egg gallery paralleling the wood grain. Larvae are present from midsummer until the next June. Adult beetles are shiny, black, and about one-eighth inch in length. A side view shows that the end of an adult's abdomen is incurved (fig. 52).
Similar damages
Secondary bark beetles attacking grand fir may be mistaken for the fir engraver, but distinct gallery pattern and beetle shape distinguishes it from associates. Root disease is often a precursor.\
References
Anonymous. 1982. For. Insect & disease identification and management. USDA For. Serv., Northern Region; Idaho Dept. of Lands, Insect and Disease Control; Montana Dept. of State Lands, Division of Forestry. 192 p.
Furniss, R. L., and V. M. Carolin. 1977. Western For. Insects. USDA Forest Serv., Misc. pub. 1339, 654 p., illus.
Stevens, R. E. 1971. Fir engraver. USDA For. Serv., For. Pest Leaflet 13, 7 p., illus.
