Professional Oak Processionary Moth Control & Removal
Oak Processionary Moth (OPM) requires specialist management because it can affect both the health of oak trees and the wellbeing of people and animals nearby.
Oxleas Tree Care provides professional OPM surveys, management and removal services across London, South East London and surrounding areas. Our trained team can inspect oak trees for signs of infestation, assess the extent of the problem and recommend an appropriate course of action.
OPM should not be approached or removed without suitable training and protective equipment. The caterpillars develop thousands of tiny irritating hairs, and these hairs can also remain within old nests after the caterpillars have gone.
Whether you are responsible for a single oak tree in a residential garden or a large number of trees across a commercial, educational or public site, early identification and appropriate management can help reduce the risks associated with OPM.
What Is Oak Processionary Moth?
Oak Processionary Moth, scientifically known as Thaumetopoea processionea, is a moth whose caterpillars primarily feed on oak trees.
The caterpillars are named after their distinctive behaviour of moving together in nose-to-tail processions. As they develop, they form silken nests on the trunks and branches of oak trees.
Repeated or severe feeding can weaken affected oak trees, particularly when combined with other environmental pressures, pests or diseases.
The greater concern around homes, schools, parks, workplaces and public spaces is the large number of irritating hairs produced by the caterpillars.
How to Identify Oak Processionary Moth
Signs of OPM can vary according to the time of year and the caterpillars’ stage of development.
Things to look for can include:
- Groups of caterpillars on oak trees
- Caterpillars travelling in distinctive processions
- White silken trails on trunks and branches
- Silken nests attached to trunks or branches
- Grey or brown older nests
- Areas of foliage that have been heavily eaten
- Groups of caterpillars gathering together
OPM nests are generally found on the trunks and branches of oak trees rather than among the leaves.
Do not approach a suspected nest simply to identify it more closely. If you think OPM may be present, keep people and animals away from the affected area and seek professional advice.
Why Is OPM a Health Risk?
As OPM caterpillars mature, they develop thousands of microscopic irritating hairs.
Contact with these hairs can cause symptoms including:
- Itching
- Skin rashes
- Eye irritation
- Sore throats
- Breathing difficulties
- Allergic reactions
The hairs can be released when caterpillars or nests are disturbed and may also be carried by the wind.
This means direct contact with a caterpillar is not necessary for exposure to occur.
Children, pets and people spending time beneath affected trees may be particularly vulnerable because they can unknowingly approach caterpillars, fallen nests or contaminated areas.
Why Old OPM Nests Can Still Be Hazardous
An empty nest does not necessarily mean that the health risk has disappeared.
OPM nests contain shed hairs and cast skins from the caterpillars. These irritating hairs can remain hazardous for a considerable period after the caterpillars have left the nest.
Old nests should therefore not be touched, broken apart or removed as a DIY task.
If you discover what appears to be an old OPM nest on an oak tree or on the ground beneath it, keep people and animals away and seek professional advice.
Do Not Attempt to Remove OPM Yourself
OPM nest and caterpillar removal is specialist work.
Disturbing a nest without the correct procedures and protective equipment can release large quantities of irritating hairs into the surrounding environment.
You should not:
- Touch OPM caterpillars
- Touch or disturb OPM nests
- Attempt to knock nests from trees
- Try to remove nests yourself
- Allow children near affected trees
- Allow pets to investigate caterpillars or nests
Professional OPM work requires appropriate procedures, specialist equipment and personal protective equipment to reduce exposure to the irritating hairs.
Our OPM Management Services
Oxleas Tree Care provides a comprehensive approach to OPM management based on the condition of the tree, the extent of the infestation, the time of year and the location of the affected trees.
Our services can include:
- OPM surveys and inspections
- Identification of suspected infestations
- Assessment of affected oak trees
- OPM nest removal
- Caterpillar management
- Ongoing monitoring
- Advice for tree owners and site managers
- OPM management alongside other arboricultural work
For sites containing multiple oak trees, regular inspection and monitoring can help identify infestations before they become more extensive.
OPM Surveys & Early Detection
Regular inspection of oak trees is an important part of managing OPM.
The signs present on a tree change throughout the year. Young caterpillars can be difficult to see, while nests become more noticeable later in the season.
Surveys can help identify:
- Active caterpillar populations
- New nests
- Older or spent nests
- Feeding damage
- Trees requiring closer monitoring
- Areas where public access may need to be managed
For organisations responsible for multiple oak trees, a planned survey and monitoring programme can provide a more systematic approach to OPM management.
Safe OPM Nest Removal
Once OPM caterpillars reach their later developmental stages, nest removal can form an important part of management.
Specialist methods can be used to remove nests and contaminated material while reducing the risk of irritating hairs becoming dispersed.
The appropriate approach depends on factors including:
- The stage of the OPM lifecycle
- Location and accessibility of the nest
- Height of the affected tree
- Number of nests present
- Surrounding public access
- Proximity to homes, schools, roads or workplaces
- Overall condition of the tree
Every situation should be assessed individually before removal work begins.
When Is OPM Most Active?
OPM follows a seasonal lifecycle.
Caterpillars generally emerge during spring and develop through several stages before forming more substantial nests later in the season. The period when caterpillars and their irritating hairs are present requires particular care around affected oak trees.
The appropriate management method can depend on the stage of the lifecycle.
Early-stage caterpillars may be managed differently from older caterpillars and established nests. This is why correct identification and timing are important when planning OPM control.
Old nests and their hairs can remain a hazard even outside the main caterpillar season.
OPM Treatment & Management
There is no single treatment suitable for every OPM infestation.
Management options depend on the caterpillars’ stage of development, the location of the tree, the level of infestation and the applicable official guidance.
Younger caterpillars may be suitable for appropriately timed treatment, while physical removal of caterpillars and nests is commonly used at later stages.
Professional assessment helps determine an appropriate management strategy rather than applying the same method to every affected tree.
OPM on Trees in Schools & Public Areas
OPM requires particular attention where affected oak trees are located in areas frequently used by people.
These can include:
- Schools and nurseries
- Parks
- Housing developments
- Communal gardens
- Commercial premises
- Public footpaths
- Car parks
- Residential estates
- Sports grounds
- Healthcare sites
Where OPM is suspected, access to the immediate area may need to be managed until the infestation has been professionally assessed.
Oxleas Tree Care can work with organisations responsib
Commercial OPM Management
Managing OPM across an estate or commercial property requires a more structured approach than dealing with an individual garden tree.
Oxleas Tree Care can provide OPM services for:
- Businesses
- Schools
- Housing associations
- Property management companies
- Local authorities
- Commercial landlords
- Contractors
- Public-sector organisations
- Estates and larger landowners
Where multiple oak trees are present, surveys can be used to identify affected trees and prioritise work according to the level of risk and the use of the surrounding area.
Ongoing monitoring can then help identify further activity and inform future management.
Working on Oak Trees Where OPM Is Present
OPM can also affect normal tree surgery operations.
Before carrying out work on oak trees in areas affected by OPM, trees should be checked for evidence of caterpillars, nests or previous infestation.
If OPM is present, additional precautions may be necessary to protect tree surgeons, customers, members of the public and animals and to reduce the risk of spreading contaminated material.
This makes it particularly important to use tree surgeons who understand OPM management when pruning, removing or otherwise working on affected oak trees.
Reporting Oak Processionary Moth
Suspected OPM sightings should be reported through the official reporting system so that the spread and distribution of the pest can be monitored.
If you believe you have found OPM, avoid unnecessary contact with the tree, caterpillars or nests while obtaining photographs or information.
Our team can advise on the next steps when assessing a suspected infestation.
OPM Removal Across London & the South East
Oxleas Tree Care provides specialist OPM management services across London, South East London and surrounding areas.
Our team works with residential, commercial and public-sector customers requiring professional inspection and management of affected oak trees.
Whether you have discovered a suspected nest in a garden or are responsible for multiple oak trees across a larger site, contact us for advice and professional assessment.
Oak Processionary Moth FAQs
What is Oak Processionary Moth?
Oak Processionary Moth is an invasive moth species whose caterpillars feed primarily on oak trees. The caterpillars can damage oak foliage and develop thousands of microscopic irritating hairs that can affect people and animals.
How can I tell if my oak tree has OPM?
Common signs include groups of caterpillars, nose-to-tail processions, silken trails and nests on the trunks or branches of oak trees and noticeable feeding damage to leaves. Professional inspection is recommended if you suspect an infestation.
Are OPM caterpillars dangerous?
The caterpillars develop irritating hairs that can cause skin rashes, itching and eye or throat irritation. Some people can experience breathing difficulties or allergic reactions.
Can OPM affect dogs and other animals?
Yes. Animals can also be affected by exposure to OPM hairs. Pets should therefore be kept away from suspected caterpillars, nests and affected areas.
Can I remove an OPM nest myself?
No. OPM nests and caterpillars should not be handled without appropriate training, protective equipment and specialist procedures. Disturbing a nest can release irritating hairs into the surrounding area.
Are old OPM nests still dangerous?
Yes. Old nests can contain large numbers of shed hairs and cast skins. These hairs can remain hazardous after the caterpillars have left.
When is OPM most active?
The caterpillars generally emerge during spring and develop through spring and early summer. The exact timing varies with seasonal conditions. Old nests and irritating hairs can, however, remain present outside the main active period.
Does OPM kill oak trees?
OPM caterpillars feed on oak leaves and can weaken trees through defoliation. Healthy trees can often recover from individual episodes, but repeated defoliation can place trees under additional stress and make them more vulnerable to other problems.
Do OPM sightings need to be reported?
Suspected OPM should be reported through the official reporting process so that its distribution can be monitored. Professional inspection can help confirm whether the caterpillars or nests are likely to be OPM.
Can you manage OPM across multiple trees?
Yes. Oxleas Tree Care can provide surveys, inspections, nest removal and ongoing OPM management for sites containing multiple oak trees, including schools, housing developments, commercial properties and public-sector sites.
What our Clients Say
Trusted by Leading Businesses and Organisations
Our experience extends beyond residential tree surgery.
Oxleas Tree Care has worked with established businesses, contractors, local authorities and public-sector organisations, demonstrating our ability to undertake professional tree works across a wide variety of sites.
From individual projects to larger commercial requirements, we bring the same focus on safety, reliability and professional workmanship to every job.
Accredited Tree Surgeons You Can Trust
Professional Standards. Recognised Accreditations. Proven Experience.
Our accreditations reflect our commitment to professional standards, health and safety and high-quality tree surgery.
For residential customers, these standards provide reassurance that their trees and property are being managed professionally.
For commercial and public-sector clients, our accreditations support the compliance, health and safety and contractor-management requirements associated with larger tree work programmes.