Oak processionary moth caterpillars

Warnings have been issued to residents after an infestation of a toxic moth harmful to humans and animals was discovered in the grounds of Bethlem Royal Hospital in West Wickham.

The oak processionary moth causes itchy skin and sore throats in people and can destroy whole trees.

The Forestry Commission is working with Bromley Council to eradicate the outbreak.

Confirmation of the infestation was received from the Commission last Wednesday (4) when a 500-metre monitoring zone was 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 dogs 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, portfolio holder for the environment said: “It is important that dog walkers in particular, through to youngsters messing around having fun in general, remain hyper 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.” South East England director for the Forestry Commission, Alison Field said: “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.”

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.

What to do if you are affected

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 020 8313 4471.

If the affected tree is within the Croydon Borough, individuals can call Croydon Council’s contact centre on 020 8727 6000 to report suspected sightings.

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.

The NHS Direct number is 0845 4647, and health information is available from the HPA website, http://www.hpa.org.uk.