Oak Processionary Moth
Treatment & Nest Removal
Specialist Oak Processionary Moth (OPM) treatment and nest removal using approved control methods.
We use electrostatic spraying with Dipel® during the treatment season and manual nest removal where required, carried out by trained operatives to protect people, pets and trees.
OPM treatment process
- Site assessment & risk assessment
- Electrostatic Dipel® treatment
- Manual nest removal
- Controlled waste handling & disposal
What is Oak Processionary Moth?
Oak Processionary Moth (OPM) is an invasive caterpillar species that feeds on oak trees.
The caterpillars form distinctive silken nests on trunks and branches and are most active during late spring and early summer.
OPM can weaken oak trees through repeated defoliation and poses a public health risk due to the microscopic hairs carried by the caterpillars.
Why OPM requires professional management
- Can cause skin irritation and health reactions
- Risk to children, pets, and the public
- Repeated infestations weaken oak trees
- Nests must not be disturbed or removed by hand
OPM nest attached to oak branch
OPM treatment and nest removal explained
OPM management depends on the stage of the caterpillars, the time of year, and the level of risk to people and property. Different approaches are used at different stages.
Electrostatic spray treatment
Electrostatic application of Dipel® is carried out during the active treatment season, typically between April and June, allowing accurate coverage of affected oak trees while targeting Oak Processionary Moth caterpillars.
- Electrostatic application equipment
- Dipel® biological treatment
- Typically carried out April–June
- Applied following site assessment
Manual nest removal
Where nests are established or identified outside the spray treatment period, trained operatives carry out controlled manual removal using appropriate PPE and approved working methods.
- Manual removal techniques
- Specialist PPE
- Controlled containment
- Safe disposal
Health and public safety risks
Key risks include
- Skin irritation and allergic reactions
- Eye and respiratory discomfort
- Risk to children, pets, and livestock
- Public access areas require controlled exclusion
- Nests must not be disturbed or handled
Compliance, training and safe working
Oak Processionary Moth management must be carried out in line with strict health, safety, and environmental controls.
Our operatives are trained to assess risk, implement exclusion zones, and carry out treatment or removal using approved methods designed to protect the public, wildlife, and the surrounding environment.
- Trained and competent operatives
- Site-specific risk assessments (RAMS)
- Appropriate PPE and exclusion controls
- Waste handled and disposed of safely
- Experience working on public and sensitive sites
Working safely on public and private land
- Schools, parks, and highways
- Commercial and residential sites
- Local authority environments
- Sensitive or high-footfall locations
When OPM treatment is required
Oak Processionary Moth management is time-sensitive. The appropriate treatment method depends on the life stage of the caterpillars and the level of risk to people, animals, and property.
Different approaches are required at different points in the season.
Spray treatment (April–June)
Electrostatic application of Dipel® is carried out during the caterpillar stage to reduce populations before nests fully develop.
Manual nest removal (July onwards)
Once nests have formed, treatment changes to manual removal using trained operatives and specialist equipment.
Nests found outside the normal season (Year-round)
If Oak Processionary Moth nests are identified at any time of year, they can still be assessed and removed using approved manual methods where required.
OPM risk period
Seasonal risk varies — early action reduces exposure
- Peak activity: April–July
- Manual nest removal: July onwards
- Nest removal available year-round when required
- Site assessment determines the appropriate control method
Typical Oak Processionary Moth nest visible on oak trunks during late spring and summer.
What to do if you suspect Oak Processionary Moth
If you believe Oak Processionary Moth may be present, it is important to take appropriate precautions. OPM nests and caterpillar hairs pose a health risk and must not be disturbed.
- Do not disturb the nests or caterpillars. OPM nests must not be handled or disturbed. Even old nests can contain harmful hairs that remain active in the environment.
- Keep people and pets away. Restrict access to the affected area where possible, particularly for children, pets, and livestock.
- Report the affected tree for assessment. Activities that disturb nests or surrounding areas can cause microscopic hairs to become airborne and increase exposure risk.
- Arrange professional treatment or removal.
A trained assessment will confirm whether OPM is present and determine the appropriate treatment or control measures.
Recommended next step
Important safety advice
- Do not attempt removal yourself
- Do not burn or vacuum nests
- Avoid contact with affected trees
- Follow public health guidance
