Press release

New legislation to protect against Oak Processionary Moth impacts

New legislation comes into force to allow movement of large oak trees within operational zones and boundaries in place to help manage Oak Processionary Moth.

This was published under the 2022 to 2024 Sunak Conservative government

Oak processionary moth caterpillars travel in nose to tail processions. Image: Henry Kuppen/ Forestry Commission

New legislation to allow the movement of large oak trees and trade within the operational zones and boundaries in place to help manage Oak Processionary Moth (OPM) is  being introduced today (24 May).

OPM is a tree pest first identified in London in 2006 which has spread to some surrounding counties in the South-East of England. Its caterpillars feed on the leaves of several species of oak trees, causing them to lose their leaves, negatively impacting their growth, and making them more vulnerable to other stresses, such as drought. When touched by members of the public, they can cause itchy rashes, eye, and throat irritations. The period between June and August  provides the greatest risk to health as this is when the caterpillars emerge.

The Forestry Commission has in place operational zones and boundaries aimed at managing OPM. In March, in response to government surveillance, the Established Area in which OPM is established and the Buffer Zone in which an annual programme of OPM management takes place, was expanded.

From today, a new demarcated area will be established around the Buffer Zone and Established Area, enabling large oak trees (girth at 1.2m above the root collar of 8cm or more) to be moved within this boundary, provided that the trees are moved by professional operators and that biosecurity requirements are met along with movement restrictions.

Professor Nicola Spence, UK Chief Plant Health Officer, said:

Healthy oak trees are a vital component of a biodiverse and thriving environmental landscape. They are Great Britain’s most important tree for species biodiversity, supporting over 2000 species of bird, mammal, fungi, invertebrate, bryophyte and lichen.

This is why it is essential that to protect the health of our oak trees, we have regulations in place for the movement of large oak trees within the zones and boundaries designed to manage Oak Processionary Moth.

Andrew Hoppit, Oak Processionary Moth Project Manager, said:

Oak Processionary Moth is a tree pest which can have a negative impact on tree health, and which can cause itchy rashes, eye, and throat irritations, when in physical contact with humans and pets.

While we understand the importance of professional operators being able to move large oak trees, it is vital that we have in place stringent biosecurity requirements to ensure a risk-based approach for moving these trees.

Large oak trees will be able to be moved within the established area, or into the established area from the buffer zone, providing the following biosecurity requirements are met:

  • Biosecurity competence – Professional operators must demonstrate that they meet the Plant Health Management Standard evidenced through membership of the Plant Healthy Certification Scheme or provision of a Ready to Plant approval from Fera Science Ltd for each consignment to be moved. They must also demonstrate evidence of ongoing on-site monitoring for OPM and inspection of OPM prior to movement.

  • Official inspections – Professional operators must keep accurate records of the of the contact details of those receiving large oak trees, including the delivery address and contact details. They must store this information for a minimum of three years to ensure traceability of movements. This information can be recorded using the Post planting Inspections form .

Large oak trees will be able to be moved within the buffer zone if they meet two additional biosecurity requirements:

  • Phytosanitary treatments – Professional operators must have a robust control regime in place with appropriate phytosanitary treatments. These treatments must be applied in line with Defra Guidance on application of phytosanitary treatments for the control of Oak Processionary Moth (Thaumetopoea processionea) 2023 and records of all treatment applications must be kept for a minimum of three years.

  • Post-planting inspections – Professional operators must disclose the potential for post-planting inspection as part of the new legislation to buyers at the time of purchase. A proportion of high-risk large oak movements within the buffer zone will be subject to post-planting inspections by the plant health inspectors.

To protect the area free from the pest it will not be permitted to:

  • Move large oak trees with OPM
  • Move large oak trees from the Established Area or Buffer Zone into the Area Free from the Pest
  • Move large oak trees from the established area into the buffer zone
  • Move large oak trees from the established area or buffer zone into the 10km exclusion zone at the outer edge of the buffer zone boundary

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

Professional operators who are growing or moving large oak trees, and who are impacted by the new movement restrictions, should consult with their local Plant Health inspector or the Plant Health and Seeds Inspectorate for further advice. For further information on the new movement restrictions, please view our digital guide and video explaining these changes. Please also view our interactive map showing the locations of recent confirmed reports of OPM and the national management zones to see how the changes affect you.

This announcement follows Plant Health Week 2023 which raises awareness of the impacts of invasive non-native species and the simple things that everyone can do to help protect the environment. By identifying threats such as pests and diseases, we protect the benefits plants provide to the public, to wildlife, the environment and our economy. More information can be found on the Plant Health Action.org website.

Further information

  • Earlier this month, we released our annual warning communications for OPM, to raise public awareness of the pest and increase biosecurity as the greatest risk period for begins.

  • In March, The Forestry Commission announced an update to the operational zones and boundaries to manage the spread of OPM. In response to government surveillance in 2022, the Established Area in which eradication of OPM is not possible, and the Buffer Zone where an annual programme of OPM management led by the Forestry Commission takes place, were expanded.

  • To view the zones the large oak trees you want to move are currently in, and what zone they would be moved to, you can use the Forestry Commission interactive map and search by postcode.

  • Last year, Defra and the Forestry Commission launched a new grant to support local communities to respond to OPM in the Established Area within London and the South-East.

  • It pays for a facilitator to form a group of land managers with oak trees on their land, create an OPM management plan for the group, as well as the hire of contractors to survey their oak trees for OPM.

  • Earlier this month we introduced a new biosecurity capital item within the Tree Health Pilot’s grant offer for OPM to fund signage and biosecurity items including boot cleaning equipment and red tape/posts for cordoning off areas.

  • For more information and details of how to apply see Grants for oak with oak processionary moth (OPM) - GOV.UK (www.gov.uk)

Biosecurity requirements

  • Small oak trees can be moved within GB without movement restrictions, other than plant passporting.

  • The biosecurity requirements will not apply if the large oak trees are in transit for less than 48 hours before moving to the final planning site. However the final destination of large trees and recipient contact details must be recorded for tracing purposes and recipients must be notified of the potential for post planting inspection; or if the large oak trees you want to move have been grown throughout their entire life with complete physical protection against the introduction of OPM, which have been inspected at appropriate times, and which are found to be free.

How to identify Oak Processionary Moth caterpillars

  • 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 which contain proteins which can cause itchy rashes, eye, and throat irritations. They can also occasionally cause breathing difficulties in people and pets, so should not be touched under any circumstances.

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

Updates to this page

Published 24 May 2023