Oak Processionary Moth (OPM) Removal
Found caterpillars or nests on an oak tree? Treecology can inspect your trees, confirm whether you have Oak Processionary Moth (OPM), and safely remove and dispose of the nests away from your property.
We have specialist equipment for OPM removal work, so our team can safely deal with infestations without spreading the hazardous hairs to you, your family or your pets.
Oak processionary moth removal service
Site visit and identification
We confirm whether the caterpillars are OPM or a harmless lookalike such as ermine moth.
Advice on control
We talk you through the control measures suitable for your trees and your site.
Clear quotation
You receive a written quotation covering removal and safe disposal of nests away from your property.
Safe removal
Our team uses specialist equipment and protective clothing to remove nests without spreading hairs.
Reporting done for you
We can report the infestation to the Forestry Research Tree Alert database on your behalf.
Treecology is a family-run tree surgery business with over 20 years of experience, we are an ARB Approved Contractor. We carry out OPM inspections and nest removal across Essex, Hertfordshire, Cambridgeshire, Suffolk and London. See our Areas We Cover page for details.
Why oak processionary moth needs a professional
Oak processionary moth is a tree pest whose caterpillars feed on oak leaves. It is established across most of Greater London and parts of the surrounding counties, and we are seeing it more and more on oak trees in Essex and Hertfordshire.
The caterpillars carry thousands of tiny hairs that can cause painful rashes, eye irritation and breathing problems in people and pets. The hairs are easily disturbed, so nests should only ever be removed by a trained team with the right equipment.
Government guidance also makes oak tree owners in the OPM established area responsible for surveying and controlling OPM on their own trees, so it is worth acting quickly if you have oaks on your land.
How to identify oak processionary moth
You may have OPM on an oak tree if you notice:
- Caterpillars with dark heads and grey bodies covered in long white hairs
- Caterpillars moving in distinctive nose-to-tail processions
- White silken nests on oak trunks or branches, which become discoloured over time
- Groups of caterpillars feeding on oak leaves.
OPM caterpillars live almost exclusively on oak. If you see webbing and caterpillars on hedges or shrubs such as hawthorn or spindle, it is more likely to be a native species.
Oak processionary moth nests
OPM nests are made of white silk and are usually rounded or teardrop shaped. They are found on the trunk and main branches of oak trees, often low enough to be within reach. Over time they turn brown and can be hard to spot. Old nests still hold thousands of shed hairs and can fall off the tree during the winter, so they remain a hazard to health even when the caterpillars have emerged as moths and left.
Is it OPM or ermine moth?
Ermine moth caterpillars are often mistaken for OPM. They spin large, dramatic webs that can cover whole hedges and shrubs, but they are harmless to people and pets. Some other native caterpillars, such as the brown-tail moth, can also irritate the skin, so if you are not sure what you are looking at, keep your distance and ask us to check. When we visit, we will confirm whether you have OPM or a harmless lookalike before recommending any work.
Oak processionary moth rash and other health risks
The caterpillars develop thousands of tiny hairs containing an irritant toxic protein. The hairs are easily blown in the wind, so you do not need to touch a caterpillar to be affected. Contact with the caterpillars, their nests or loose hairs can cause:
- Severe, itchy skin rashes
- Eye irritation
- Sore throats
- Breathing difficulties in some people
- Reactions in dogs and other animals
In rare cases, people who are sensitive to the hairs can have a severe allergic reaction (anaphylaxis).
If you think you or a family member has an OPM rash, speak to a pharmacist or call NHS 111 for advice. If someone is struggling to breathe, call 999. If your dog or another animal has been in contact with caterpillars or nests, contact your vet.
When is oak processionary moth active?
OPM caterpillars hatch in spring, usually from April, and are most active from late spring to early summer. This is when the risk is highest and when most people spot processions and new nests.
However, the hairs remain a hazard throughout the year because old nests stay on the tree or fall to the ground. Nests found in autumn and winter should be treated with the same caution and can still be removed safely by a specialist team.
What to do if you find OPM
If you see caterpillars or nests that you suspect may be OPM:
- Do not touch them
- Do not try to remove the nests yourself
- Keep children and pets away from the area
- Contact us to arrange a site visit
- Report the sighting to the Forest Research website via TreeAlert
When you report through TreeAlert, include a photograph if it is safe to take one, the location of the tree and details of how large the infestation looks. If you would rather not, we can make the report for you when we inspect the site.
Oak processionary moth FAQs
What is Oak Processionary Moth?
Oak processionary moth (OPM) is a tree pest first found in London in 2006. Its caterpillars feed on oak leaves and carry irritating hairs that are a hazard to people and animals.
Are Oak Processionary Moths dangerous?
The caterpillars and their nests are. Their hairs can cause skin rashes, eye and throat irritation and breathing difficulties, and in rare cases a severe allergic reaction. The adult moths are not considered a hazard.
What does an Oak Processionary Moth rash look like?
It is usually an itchy, red rash on exposed skin such as the arms, neck and face. If you are worried, speak to a pharmacist or call NHS 111.
Can I remove an OPM nest myself?
No. Disturbing a nest releases hairs into the air and onto your skin and clothing. Nests should be removed by trained professionals using protective equipment.
Who is responsible for OPM on my tree?
In the OPM established area, the owner of the oak tree is responsible for surveying and controlling OPM. We can inspect your trees and carry out the work for you.
How do I report Oak Processionary Moth?
Report sightings to the Forestry Commission through TreeAlert, including a photo if safe, the tree's location and the size of the infestation. We can also report it for you during our site visit.
When is the best time to deal with OPM?
As soon as you spot it. Caterpillars are most active from late spring to early summer, but old nests stay hazardous all year, so they are worth removing whenever they are found.
Worried about Oak Processionary Moth?
Do not touch the nests.
Use our contact form to tell us about the tree(s) concerned. If possible and if it is safe to do so, please provide a photo of the nest and details of the location.