Robust Action on Oak Processionary Moth

New findings of the tree pest Oak Processionary Moth (OPM) have been identified in a small area of Hampshire, following enhanced plant health surveillance activity by the Forestry Commission.

By Elle McAllister · August 1, 2022

The findings are located in a small area in Hampshire within the Pest-Free Area. Rapid and robust action is being taken to investigate and address these findings, including targeted surveys and control measures to reduce pest prevalence and minimise its spread. The Forestry Commission will continue to monitor for OPM throughout the Pest-Free Area through an extensive surveillance and trapping programme.

Andrew Hoppit, Oak Processionary Moth Project Manager, said:

“Oak Processionary Moth 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. The caterpillars have black heads and bodies covered in long white hairs. Neither should be touched under any circumstances.
Rapid plant health enforcement action is being taken to investigate and control these isolated findings in Hampshire.
Any sightings should be reported to the Forestry Commission via our TreeAlert portal, by emailing or calling 0300 067 4442. Doing so will help to protect people, minimise the pest’s spread and help to ensure our precious oak trees remain a much loved feature of the landscape.”

OPM management varies across England to reflect the known distribution of the pest and to protect uninfected areas. First identified in London in 2006, the pest has since spread to some surrounding counties in the south east of England. An annual programme of OPM surveillance and control takes place in a buffer zone around the area where OPM is established, to help protect the majority of the UK which is free from the pest.

Landowners, the public, and trade are urged to remain vigilant for the pest and report any sightings. OPM caterpillars and their nests contain hairs which can cause itchy rashes, eye and throat irritations, and should not be touched under any circumstances at any time. The caterpillars also feed on the leaves of several species of oak trees. This can cause the trees to lose their leaves, negatively impacting their growth, and making them more vulnerable to other stresses, like drought. The greatest risk period is May to July when the caterpillars emerge and feed before pupating into adult moths.

A Government programme to manage OPM has been in place since 2012 to control its spread. Over the last five years, £10 million has been invested into oak health, including the management of OPM, as well as research to develop novel control techniques.

A public information leaflet covering how to identify OPM and methods of control is available here.

For more information, visit ‘Managing Oak Processionary Moth in England’.

Further information on support for those affected by Oak Processionary Moth:

  • The OPM Groups Grant funds the surveying of oak trees within local communities in London and the South East, supporting efforts to better understand the risks and appropriate management of OPM. To ease the administrative process and encourage cooperative action in local communities, it pays for a lead facilitator to form a group of local landowners who all need support to tackle the pest. This builds on existing support and guidance available to help minimise the impact and spread of the pest.
  • The OPM Private Residents’ Pilot supports private residents with small numbers of oak trees to help with the treatment of oak.
  • A toolkit for local authorities and larger landowners to help plan for and manage OPM has been developed by the Tree Council, in partnership with Forest Research.

Wider background: