Douglas-fir beetle

Definition

A species of bark beetle in the family Curculionidae, subfamily Scolytinae, that specializes in colonizing and killing Douglas-fir (Pseudotsuga menziesii) and related conifers. Adults bore through bark to construct egg galleries in the phloem, introducing symbiotic fungi that help overcome host tree defenses and provide nutrition for larvae. Outbreaks can cause extensive timber mortality across western North American forests.

Etymology

Common name from its obligate host association with Douglas-fir; scientific epithet pseudotsugae from Pseudotsuga, the genus of its primary host.

Example

During the 1990s outbreak in Colorado, Douglas-fir beetle populations killed over 1 million acres of mature Douglas-fir, with pheromone-baited traps used to monitor flight activity and predict spread.

Synonyms

• Dendroctonus pseudotsugae

Related Terms

• bark beetle
• Dendroctonus
• mountain pine beetle
• spruce beetle
• phloem
• tree defense
• forest entomology
• aggregation pheromone

Usage Notes

Often abbreviated DFB in forest management literature. Distinguished from other Dendroctonus species by host specificity and gallery pattern: egg galleries run parallel to wood grain with larval mines extending perpendicular, creating a distinctive fan-shaped pattern visible beneath bark. The hyphen in 'Douglas-fir' follows botanical convention for the tree name; the beetle name inherits this spelling.