European pine moth

Dendrolimus pini

1. Identification

• Common name: Pine‑tree lappet
• Scientific name: Dendrolimus pini L.
• Order: Lepidoptera
• Family: Lasiocampidae

2. Pest description

• Robust caterpillars, grey to brownish in colour, with light longitudinal lines and tufts of hairs; reaching 60–70 mm.
• Large adults, with brown wings and transverse patterns; wingspan of 40–70 mm.
• Defoliating species, with very voracious caterpillars that feed on needles.
• It may form population outbreaks that cause severe defoliation in pine stands.

3. Main hosts

• Scots pine.
• Maritime pine.
• Other Pinus spp., occasionally Larix spp.

4. Symptoms and damage

• Needles partially eaten or completely consumed.
• Intense defoliation, leaving branches almost bare.
• Reduction in the vigour of trees, greater susceptibility to bark beetles and secondary agents.
• In severe outbreaks, it may cause tree mortality, especially in young or weakened stands.

5. Biological cycle

• Eggs laid in masses on the bark or on the needles, generally in summer.
• Caterpillars develop over several months, and may overwinter in silky nests in the soil or at the base of the trees.
• Pupation in the soil, in resistant cocoons.
• Adults emerge in late spring and summer; generally one generation per year.

6. Monitoring

• Direct observation of caterpillars and damage to the needles.
• Searching for overwintering nests in the soil or at the base of the trees.
• Pheromone traps for the detection of adults and tracking of flights.
• Assessment of the intensity of defoliation in pine stands.

7. Management measures

• Cultural: removal of heavily weakened trees; density management to reduce water stress.
• Preventive: regular monitoring of stands, especially in areas with a history of outbreaks.
• Biological: application of Bacillus thuringiensis in the early stages of the caterpillars; promotion of natural enemies.
• Integrated protection: definition of intervention thresholds, judicious use of authorised insecticides and integration with monitoring and trap data.

Bibliographic references

• CABI – Invasive Species Compendium – Dendrolimus pini.
• EPPO Global Database – Dendrolimus pini.
• Alford, D. V. (2007). Pest and Disease Management Handbook. Blackwell Publishing.
• Carter, D. J. (1984). Pest Lepidoptera of Europe. Dr W. Junk Publishers.
• Schmidt, G. H. et al. (1998). Population dynamics and control of Dendrolimus pini. Journal of Applied Entomology, 122, 1–10.