Oak processionary moth

The oak processionary moth (OPM) (Thaumetopoea processionea) is a pest that has been found in Surrey. It lives on oak trees and poses a risk to human and animal health.

Health risk

It's important not to come into contact with OPM caterpillars, hairs or nests as their tiny hairs can cause skin rashes and less frequently eye and throat irritations and breathing difficulties in people and animals. Pets must be kept away from the nests and caterpillars.

May to July is the greatest risk period when the caterpillars are most numerous.

What to do if you see or touch them

If you think you saw any processionary nests or caterpillars, first make sure you have correctly identified the species:

If you do come into contact with the larvae or caterpillars by accident, please follow the health advice about dealing with caterpillar hairs on the NHS website. If you have an itching skin rash and/or conjunctivitis or other symptoms, contact your GP, or call NHS 111.

Reporting OPM sightings

On privately owned land

It is the responsibility of the land owner to look at individual trees and decide what is the appropriate management needed. Elmbridge Borough Council is unable to visit privately owned areas due to the scale and scope of the problem across the borough.

What to do:

On a council-owned tree 

  • Report it to us by email at opm@elmbridge.gov.uk or telephone 01372 474825 or 01372 474579.
    We can't respond to all reports but rest assured we are following the process below with each reporting.

  • Our risk-assessment approach to each site:

    • We look at each nest according to its location, and the risk to residents and pay particular attention to densely populated areas and the proximity to vulnerable individuals, e.g. children, infants and elderly. 

    • We control high risk areas by spraying or remove nests manually, where appropriate, and manage low risk areas through on-site information.

On highways trees

Report to Surrey County Council Highways 

On land managed by PA Housing 

Report to PA Housing.

What next?

If you have any doubt or want further information please feel free to email us at opm@elmbridge.gov.uk or call 01372 474579.

Date updated: 15 June 2022

Image of oak processionary moth
Oak processionary moth nest

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