Large larch bark beetle

Ips cembrae

1. Identification

• Common name: Large larch bark beetle
• Scientific name: Ips cembrae Heer
• Order: Coleoptera
• Family: Curculionidae (subfamily Scolytinae)

2. Pest description

• Adults: Scolytids of 4–6 mm; cylindrical dark-brown body; elytral declivity with six teeth on each side, similar to those of Ips sexdentatus but generally more robust; most intense activity in spring and summer.
• Larvae: Apodous, whitish, with a curved body and brown head; develop in galleries beneath the bark.
• Pupae: Whitish, formed in pupal chambers inside the bark.
• Galleries: Typical system with a central nuptial gallery and well-defined radial larval galleries.

3. Main hosts

• Larch as the main host.
• It may also occur on other conifers, including Picea and Pinus, especially on weakened trees.

4. Symptoms and damage

• Bark perforations with the expulsion of fine sawdust.
• Subcortical galleries that interrupt the flow of sap.
• Progressive drying of the crown, starting at the top.
• Yellowing and premature fall of the needles.
• Tree mortality in intense or successive attacks.
• Possible association with pathogenic fungi carried by the adults.

5. Biological cycle

• Two annual generations in most regions, with a third possibly occurring in warm years.
• Adults emerge in spring and begin excavating egg-laying galleries.
• Eggs laid in the nuptial gallery; larvae excavate radial galleries.
• Pupation beneath the bark; new adults emerge and may start new generations.
• Development favoured by hot summers, prolonged droughts and an abundance of weakened wood.

6. Monitoring

• Observation of recent perforations and the expulsion of sawdust.
• Inspection of crowns showing yellowing or drying.
• Assessment of galleries beneath the bark on suspect trees.
• Reinforced monitoring after storms, drought periods or tree falls.
• Use of 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: Maintaining stand vitality; reducing water stress; avoiding trunk wounds.
• Integrated protection: Use of traps with pheromones for monitoring; intervention only when necessary; practices that reduce the availability of attractive wood.

Bibliographic references

• CABI Invasive Species Compendium – Ips cembrae.
• EPPO Global Database – Ips cembrae.
• Wermelinger, B. (2004). Ecology and management of bark beetles in European conifer forests.
• Lieutier, F., et al. (2004). Bark and wood boring insects in living trees in Europe.