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Knowledge Centre

Oak Processionary Moth: guides and resources

Reference material for anyone who needs to understand OPM properly — from a homeowner with one oak to an estates team responsible for hundreds.

Core guides

Start here

What is Oak Processionary Moth?

Biology, arrival in the UK, distribution and impact on oak trees and people.

How to identify OPM

Caterpillars, processions, nests, feeding damage and egg plaques.

Caterpillars mistaken for OPM

Brown-tail, tussock moths, spindle ermine, lackey and vapourer moths.

OPM health risks

How the hairs cause harm, symptoms in people and animals, and precautions.

Found OPM? What to do next

The five steps, what never to do, and how to report a suspected sighting.

OPM management explained

Surveys, mapping, monitoring, exclusion, nest management and annual programmes.

Send Photo Report OPM