Oak processionary moths

The oak processionary moth (Thaumetopoea processionea) is a pest that has established itself within the borough since2005. It lives on oak trees and poses a risk to human and animal health.

Health risk

The caterpillar of this moth emerges in April every year and develops thousands of urticating (irritating) hairs, which can cause skin rashes, sore throats, breathing difficulties and eye problems if you or your pet comes into contact with them.


Each year we employ specialists to treat oak trees to prevent the caterpillars from developing into a hazardous state, and to survey and remove nests.

What to do if you see or touch them

If you see any oak processionary nests or caterpillars (OPM) you should report them immediately.

It is important not to come into contact with the caterpillars, hairs or nests. The Forestry Commission has produced a leaflet with further information on how to protect yourself and what to do if you or others are affected(pdf, 15798KB).

If you think you may have been exposed and have an itching skin rash and/or conjunctivitis or other symptoms see a pharmacist to relieve the symptoms, or, if you have a more serious allergic reaction, contact your GP or call NHS Direct on 111. The call is free from any phone.

Similarly, consult a vet if your pet has a serious reaction. (It is important to restrain pets from approaching nests or caterpillars).

Advice for contractors

Regulations are in place which affects how contractors working with Oak trees should be handling material within the Oak Processionary Moth affected areas. The Forestry Commission have produced a guidance document with further details.


Find out more about the oak processionary moth on the Forestry Commission website.

OPM nest   OPM caterpillars in procession   OPM caterpillar

Updated: 8 January 2018