Most Unwanted: Pine Processionary Moth

Human health risk: the caterpillars are covered in toxic irritating hairs. Do not get close to larvae or their nests. Take notice of any warning signs in place.

How to identify the Pine Processionary Moth (Thaumetopoea pityocampa)


  • In about January, the caterpillars build tent-like white nests near the tops of Pine trees, which can sometimes be as big as a football
  • The most distinctive life stage is the caterpillar, which is orange-brown with bluish-grey bands and covered in dense clumps of hairs
  • Caterpillars are most likely to be seen in winter and early spring
  • They often form wedge-shaped processions, moving head-to-tail
  • Adult moths have cream forewings with brown markings
    and white hindwings, and can be seen in May to July
  • They cause defoliation of Pine needles.

Plants affected:

  • Pine trees

UK status and other information:

  • Not yet present in the UK
  • One population of caterpillars was found in a UK nursery in 1995 on Scots Pine imported from Europe, but it did not become established
  • Since the 1990s, this moth has been moving north through France and is now just across the Channel in Normandy and Brittany
  • Although the moths are not strong fliers, they could still be carried across the Channel to the UK.

Why will any findings be important?

  • The caterpillars feed on the needles, causing severe defoliation in some cases
  • Early sightings will help to control their spread.

Could be confused with:

  • The Oak Processionary Moth, which has some similarities, but is more likely to be found on Oak trees, and seen at different times of year.

Useful links:


Images: Caterpillars © Francois-Xavier Santonge, nest © John Ghent