Oak processionary moth outbreak

Bromley residents are being advised to be vigilant after the discovery of oak processionary moth caterpillars near West Wickham. As well as causing damage to oak trees, the caterpillars of this moth can pose a risk to human and animal health. Residents in the local area are therefore being reassured that action is already being taken to remove the nests and are being asked to report any sightings. Bromley Council’s tree team are working closely with the Forestry Commission following confirmation of the outbreak and a 500-metre exclusion zone has been set up around the main affected woodland in those parts of Bethlem Royal Hospital’s grounds which are accessible to the public.

Residents are strongly advised not to touch the caterpillars or interfere with the nests as the microscopic hairs from the caterpillars contain a toxin that are known to cause itchy skin rashes, itchy eyes and a sore throat. If individuals suspect that they have been exposed to the caterpillar’s hairs and have these symptoms they should contact their GP or NHS Direct, advising them of the potential contact they have had. Animals such as dogs can also be affected by the caterpillar’s hairs and dog walkers are advised to be vigilant when exercising their dog in woodland settings and not to let curious dogs investigate the caterpillars or their nests, which can sometimes fall to the ground.

Councillor Colin Smith, Executive Councillor for the Environment said, “It is important that dog walkers in particular, through to youngsters messing around having fun in general, remain vigilant as this pest represents a potentially extremely serious health issue for anybody who comes into contact with it. It is not only a health hazard to humans but also threatens loved pets as the hairs of the caterpillars are toxic and so should not be touched under any circumstances. It is also a threat to our trees themselves, so I would please urge everyone from residents in side-roads, through to Country hikers to please be aware and report without hesitation, any possible sittings of this outbreak across the Borough.”

Alison Field, South East England Director for the Forestry Commission, endorsed the Council's advice. She explained, "Large populations can defoliate whole oak trees by eating the leaves, leaving them weakened and less able to withstand other threats, so we need to control this pest to protect our beautiful oak trees as well as human and animal health." 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 toxic hairs. To be as effective and safe as possible this job needs to be done by people with the right training and equipment, and the nests must be disposed of properly.”


As the name suggests, the oak processionary moths are predominantly found on oak trees though they are not known to be fatal to fauna. Where the Forestry Commission confirms cases a plant health notice is issued and then specialist contractors are required to remove the caterpillars. Residents are strongly advised not touch or try to dispose of the insects themselves. Specialist contractors must be used in every case.

If caterpillars or their nests are seen, individuals should contact Forest Research (Forestry Commission) on 01420 22255 or email christine.tilbury@forestry.gsi.gov.uk. If caterpillars are spotted on street trees in Bromley borough, or on Bromley Council owned woodland or green spaces, this should be reported to Bromley Council’s tree team 0208 313 4471.

People who are having oak trees pruned or felled in affected areas must contact the Forestry Commission’s Plant Health Service beforehand on plant.health@forestry.gsi.gov.uk or 0131 314 6414 for advice about safe removal of the material. The Plant Health Service can also supply details of suitably qualified pest control operators who can remove infestations.
The NHS Direct number is 0845 4647

More information can be found at the following websites:-

• Wikipedia Oak Processionary
• Forestry Commision
• PDF file from Forestry commision