Great spruce bark beetle : Observatree guides

The great spruce bark beetle (GSBB, Dendroctonus micans) causes damage to spruce trees (Picea spp.) by tunnelling into the bark of living trees. On hatching, the developing larvae excavate feeding tunnels and galleries in the inner living bark layers. When beetle galleries completely girdle the stem, the part of the infested tree above the wound will ultimately die. This may take several years of sustained attack, with large breeding populations accumulating before individual trees are killed, creating a risk of spread to nearby trees.