Borough Insight

Oak processionary moth

If you have been out and about within the borough, you may have seen one of the posters our Rangers have put up near trees that have been infected by oak processionary moth (OPM).

OPM 1OPM was first accidentally introduced to England in 2005, and is subject to a government-led programme of survey and control to minimise its population, spread and impacts. OPM gets its name from the distinctive processing behaviour of the caterpillars because they tend to move in nose-to-tail lines. 

OPM is present within the borough at various locations.

The caterpillars of OMP are pests of oak trees and a hazard to human and animal health.

Older caterpillars develop tiny hairs and contact with the hairs can cause itching skin rashes and eye irritations, sore throats, breathing difficulties and, rarely, allergic reactions in people and animals. The caterpillars should not be handled nor approached.

The caterpillars can shed the hairs when threatened or disturbed. The hairs can be blown by the wind, and they accumulate in the caterpillars’ nests, which can fall to the ground. They can stick to trunks, branches, grass and clothing.OPM 2

Among the groups most vulnerable to the health hazards are:

  • curious children and pets
  • people who work on or close to oak trees
  • anyone spending time close to infested trees
  • grazing and browsing livestock and wild animals.

Adults and children must see a doctor immediately if they have come into contact with OPM and begin to suffer symptoms.

If pets or livestock come into contact, they should be removed from the area and a vet should be contacted.

If you think you’ve spotted this disease please inform the Forestry Commission using the Tree Alert reporting tool and our contact centre



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