Ips typographus (European Spruce Bark Beetle) - Fact Sheet

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Identification

Adults are 4.2 to 5.5 mm long, cylindrical and reddish or dark brown to completely black.^{2, 4, 131, 136} The front of the head and the sides of the body are covered with long yellowish hairs.¹ Both sexes have four spines on each side of the elytral declivity, with the 3^rd spine being the largest and capitate.⁴ However, males have a larger head on the 3^rd spine than do females and have fewer hairs on the pronotum.^{2, 3, 97}

Host Trees

Picea (main host), Abies, Larix and Pinus.^{1, 4, 136}

Location Of Infestation Within The Tree

Larvae feed in the inner bark up to 10 m along the stem.^{35, 133, 136} This species prefers thicker-barked stems with a minimum bark thickness of 2.5 mm and an optimum thickness of 5.0 mm.^{131, 134}

Host Condition

This beetle prefers physiologically weakened, damaged, windthrown, recently felled or overmature trees.^{4, 35, 133} However, as populations increase healthy hosts may be attacked.^{4, 133} Infestations are more severe in stands greater than 120 years old, with a preference for trees between 70 and 150 years old. Stands less than 40 years old sustain very little damage.^{4, 5, 35, 53}

Distribution

Europe, China, North Korea, South Korea, Japan and Russia., ⁴²

Signs and Symptoms

Males excavate a nuptial chamber and are joined by 1 to 4 females. Females construct egg galleries in the inner bark radiating outward from the nuptial chamber.⁴ Vertical egg galleries are 10 to 20 cm long (12.5 cm average) and are usually three-armed, but can be two armed or multi-branched.^{1, 3, 88, 131} Approximately 50 eggs are laid on each side of the egg gallery.^{3, 97, 136} Larval galleries radiate at right angles to the egg gallery and become wider as the larvae grow.¹³⁶

On standing trees, needles turn yellow-green to red-brown and the foliage drops within a few weeks.^{1, 136} Signs of infestation include red-brown frass in bark crevices, numerous round exit holes approximately 2 to 3 mm in diameter, and small (dime sized) tubes of resin (pitch tubes) extruding from the bark.^{1, 136} Woodpecker damage may also be present.⁶

Adult beetles also carry a number of associated fungi such as Ceratocystis polonica (Siemaszko). This bluestain fungus is highly virulent and can kill healthy spruce trees.⁴ This fungus also stains the wood with blue streaks, which reduces its commercial value.⁴

Photo credits

• A Gyorgy Csoka, Hungary Forest Research Institute, Image 1231225, www.invasive.org, Jan. 5, 2004
• B Louis-Michel Nageleisen, Département de la Santé des Forêts, France, Image 1190030, www.invasive.org, Feb. 5, 2004
• C Milos Knizek, Forestry and Game Management Research Institute, Czechia, Image 1191005, www.invasive.org, Feb. 5, 2004
• D Louis-Michel Nageleisen, Département de la Santé des Forêts, France, Image 1190027, www.invasive.org, Feb. 5, 2004
• E Louis-Michel Nageleisen, Département de la Santé des Forêts, France, Image 1190031, www.invasive.org, Feb. 5, 2004
• F Petr Kapitola, Forestry and Game Management Research Institute, Czechia, Image 1191001, www.invasive.org, Feb. 5, 2004
• G Norwegian Forest Research Institute, www.skogforsk.no