New OPM Outbreak Confirmed

OPM Caterpillars

Oak Processionary Moth caterpillars found in south east London.

The Forestry Commission has confirmed that Oak Processionary Moth caterpillars (OPM) have been found in the West Wickham area of Bromley in south-east London.

The locationOPM Caterpillars is about 9 miles (15km) from the nearest known infestations in the established west London OPM outbreak, prompting the Forestry Commission to believe that it is a separate outbreak rather than an extension of the known outbreak in west London.

A group of infested oak trees in an area with public access were reported to the Forestry Commission on Wednesday 4 July by Bromley Borough Council. The area was immediately cordoned off to protect the public and pet animals from the caterpillars’ toxic hairs, and the Council called in pest control operators to remove the caterpillars and their silken webbing nests. Other oak trees in the area are being surveyed.

OPM caterpillars – the larval stage of the moths’ lifecycle – are a threat to oak trees because they eat oak leaves, and in severe cases can defoliate whole trees, leaving them vulnerable to other threats. Alison Field, South East England regional director of the Forestry Commission, said,

“It’s extremely disappointing that OPM has been found in this part of London so far from the existing outbreak in west London, where they have become established since being accidentally introduced from Continental Europe about 2005.

“The distance away from the west London outbreak suggests this is a separate outbreak, although we will be investigating the pathway by which it got to Bromley.

“We are working with Bromley Council and others involved to eradicate the outbreak as quickly as possible. The location is close to the boundary with Croydon Borough, and we have alerted Croydon Borough Council.”

Ms Field urged local people not to touch the nests or caterpillars or try to remove them, explaining:

“At this time of year the caterpillars build white, silken webbing nests in oak trees in preparation for pupating into adult moths. Tree owners should not try to remove nests themselves, because they can be full of the caterpillars’ toxic hairs. To be as effective and safe as possible this job needs to be done by specially trained and equipped operators, and the nests must be disposed of properly.”

Sightings of caterpillars or nests can be reported to the Forestry Commission’s Forest Research agency on 01420 22255; email:; or to Bromley Council’s tree team on 0208 313 4471, or to the local Council.

People who are having oak trees pruned or felled in affected areas must contact the Forestry Commission’s Plant Health Service beforehand on or 0131 314 6414 for advice about safe removal of the material. The Plant Health Service and local councils in outbreak areas can also supply details of suitably qualified pest control operators who can remove infestations.

Contact with the hairs can cause itchy skin rashes, itchy eyes and a sore throat. Anyone suspecting they have been exposed to the caterpillars and have these symptoms should contact their GP, or NHS Direct on 0845 4647, advising them of the possible contact with OPM hairs. Health information is available from the HPA website,

Get further information about OPM.

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