Eight-toothed spruce bark beetle

Ips typographus

1. Identification

• Common name: Eight-toothed spruce bark beetle
• Scientific name: Ips typographus L.
• Order: Coleoptera
• Family: Curculionidae (subfamily Scolytinae)

2. Pest description

• Adults: Small bark beetles of 4–5.5 mm; dark brown cylindrical body; elytral declivity with four teeth on each side, a distinctive feature of the species.
• Larvae: Apodous, whitish, curved body, brown head; they develop in galleries under the bark.
• Pupae: Whitish, formed in pupal chambers inside the bark.
• Galleries: Typical system with a central nuptial gallery and radial larval galleries.

3. Main hosts

• Conifer species, mainly spruces.
• It may attack other conifers, especially weakened trees, those felled by wind or affected by drought.

4. Symptoms and damage

• Borings in the bark with the expulsion of fine sawdust.
• Subcortical galleries that interrupt the flow of sap.
• Yellowing and drying of the crown, starting at the top.
• Premature needle drop.
• Tree mortality in intense or successive attacks.
• Greater risk of secondary infections by associated fungi.

5. Biological cycle

• Two to three generations per year, depending on temperature.
• Adults emerge in spring and begin excavating egg-laying galleries.
• Eggs deposited in the nuptial gallery; larvae excavate radial galleries.
• Pupation under the bark; new adults emerge and may start additional generations.
• Development favoured by hot summers, prolonged droughts and an abundance of weakened wood.

6. Monitoring

• Observation of recent borings and expulsion of sawdust.
• Inspection of crowns with yellowing or drying.
• Assessment of galleries under the bark in suspect trees.
• Reinforced monitoring after storms, periods of drought or tree falls.
• Traps with specific pheromones for detection and population tracking.

7. Management measures

• Cultural: Removal and debarking of infested trees; elimination of fallen wood; proper management of forest residues.
• Preventive: Reduction of water stress; maintenance of stand vitality; avoid wounds to the trunk.
• Integrated protection: Use of pheromone traps for monitoring; intervention only when necessary; practices that reduce the availability of attractive wood.

Bibliographic references

• CABI Invasive Species Compendium – Ips typographus.
• EPPO Global Database – Ips typographus.
• Wermelinger, B. (2004). Ecology and management of the spruce bark beetle Ips typographus.
• Fettig, C. J., et al. (2007). Bark beetle ecology and impacts in conifer forests.