Secondary-insect
Guides
Scolytus unispinosus
Douglas-fir engraver
Scolytus unispinosus, the Douglas-fir engraver, is a bark beetle native to western North America. It acts primarily as a secondary insect, colonizing the tops, limbs, and branches of Douglas-fir trees that have been killed or weakened by other factors. While it occasionally kills young trees, it is generally of minor economic importance and commonly attacks logging slash. In British Columbia's interior, it frequently occurs in association with the Douglas-fir beetle (Dendroctonus pseudotsugae).