Oak Processionary Moth identified in Derbyshire

Oak Processionary Moth (OPM) has been confirmed in oak trees in the Long Eaton area of Derbyshire. The public is being urged to report sightings of this tree pest.

By Wendy Necar · July 4, 2023

Pictured above: OPM caterpillars. Credit Maydenbury

The findings are outside OPM’s established area in London and some neighbouring counties.

The trees are currently being treated and extensive surveillance work is ongoing to prevent potential spread. Action is also being taken to identify the source of the outbreak.

OPM caterpillars have black heads and grey bodies covered in long white hairs. They usually move nose-to-tail in a procession. Nests are typically dome or teardrop-shaped, averaging the size of a tennis ball. They are white when fresh, but soon become discoloured and brown.

OPM caterpillars eat (defoliate) the oak leaves. That weakens the tree and leaves it vulnerable to other threats. Contact with the caterpillars’ hairs can cause humans and animals skin or eye irritations.

Owners and managers of oak trees are urged to give access, if required, to Forestry Commission surveyors to assess whether their trees are infested. OPM caterpillars and nests should not be touched under any circumstances.

Following possible OPM contact, visit your pharmacist for relief from milder skin or eye irritations. Consult a GP or call NHS111 for more serious reactions. Contact a vet if animals are seriously affected.

The caterpillars are likely to be visible until the end of July.

Nicola Spence, UK Chief Plant Health Officer, said:  “The Government takes the management of Oak Processionary Moth very seriously and has a robust programme in place to reduce the level of pest prevalence and protect oak resource, whilst supporting landowners to manage the risks associated with OPM in the areas where it has been identified.”

Please report potential sighting, with photos as supporting evidence, via the TreeAlert portal. Alternatively, email or call 0300 067 4442.

 More information

Pictured below: OPM nest. Credit Maydenbury