Spruce Beetle - Forest Health and Adaptation

Spruce beetles (Dendroctonus rufipennis [Kirby]) occur in endemic populations in white spruce stands throughout Alberta.

Outbreaks of the spruce beetle often originate from areas with blowdown, logging slash, or damaged standing timber. Spruce beetles breed in these areas and may attack and kill healthy trees.

Spruce beetle is common throughout Alberta, especially in areas with abundant mature spruce trees. Primary hosts include white spruce (Picea glauca [Moench] Voss) and Engelmann spruce (P. engelmannii Parry).

Signs and Symptoms

Look for the following signs and symptoms of spruce beetle infestation:

Crown

• Fading green, yellow-orange or red-brown over whole crown of mature trees.

• Fading green, yellow-orange or red-brown needles.

• Entrance holes on stem
• Pitch tubes
• Reddish-brown sawdust piles
• Woodpecker removal of bark

• blue-coloured stain
• brown-black adults (4.5 -- 7 mm long) with reddish-brown or black wing covers
• presence of white grub-like larvae with light brown heads (up to 7 mm long)
• short egg galleries with larval galleries fanning out from egg galleries

• blue-black coloured stain
• brown-black adults (4.5 -- 7 mm long) with reddish-brown or black wing covers
• galleries/tunnels
• pitch tubes
• presence of white grub-like larvae with light brown heads (up to 7 mm long)

• Can be confused with other secondary bark beetles.
• Look for the characteristic gallery pattern that follows the grain of wood in the phloem and cambium tissues.
• Pitch tubes may be found on the bark surface.
• There is usually the presence of blue stain fungi.
• Spruce beetles prefer damaged, dying or freshly killed trees.