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Warning to residents as toxic caterpillar nests spotted near a park in Bracknell

OPM caterpillars, crown copyright, Forestry Commission

Oak Processionary Moth caterpillars have been recorded on an oak tree near Clintons Hill in Bracknell.

The caterpillars contain tiny hairs that can cause eye and skin irritation, breathing difficulties and sore throats in those who come into contact with them, including people and animals. They can also affect the health of oak trees, stripping trees bare, leaving them weakened and vulnerable to other threats.

The first recorded outbreak of the moth was found in West London in 2006 and since then it has steadily spread to nearby boroughs.

Bracknell Forest Council have cordoned off the area where the nest has been spotted and have put up posters advising people to not approach the site for their safety. The Forestry Commission has advised the public to protect themselves by knowing how to recognise caterpillars and keeping pets and children away from caterpillars and nests.

Identifying Oak Processionary Moth caterpillars

Oak Processionary Moth caterpillars:

  • live almost exclusively in oak trees, which are identifiable by their distinctive leaves
  • move in nose-to-tail processions, in oak trees or on the ground, hence their name
  • often cluster together
  • build white, silken webbing trails and nests – usually dome or teardrop-shaped – on oak trunks and branches (not among the leaves)
  • have nests that soon become discoloured

If you see nests or caterpillars:

Health precautions

People in the affected areas can take these simple precautions to minimise the health risks to themselves and their pets and livestock:

Do not:

  • touch or approach nests or caterpillars
  • let children touch or approach nests or caterpillars
  • let animals touch or approach nests or caterpillars
  • try removing nests or caterpillars yourself


  • teach children not to touch or approach the nests or caterpillars
  • train or restrain pets from touching or approaching them
  • keep horses and livestock a safe distance from infested oak trees. Covering or stabling livestock can help
  • see a pharmacist for relief from skin or eye irritations after suspected OPM contact
  • call NHS111 or see a doctor if you think you or someone in your care has had a serious allergic reaction
  • consult a vet if you think your pet or livestock has been seriously affected
  • call in a pest control expert to remove infestations in your own trees
  • report any sightings to us

For more information follow the advice in this Forestry Commission leaflet for staying safe.

Andrew Hunter chief officer for planning transport and countryside said:

“We take the safety of our residents very seriously and would advise people not to disturb or handle the nests or moths as they can cause severe irritation to the skin”.

“We are now collaborating with the Forestry Commission in order to support their long standing work to control the spread of this moth and minimise the risk to the public as they continue to enjoy our parks, gardens and woodland."

Further information about the Oak Processionary Moth is available on the Forestry Commission’s website.

Image: crown copyright, Forestry Commission.