Residents of north-west and south-west London are once again being asked for help in the effort to get rid of the pest oak processionary moth from the area.
Their caterpillars have begun building their distinctive white, silken nests in oak trees in the Ealing, Brent, Hounslow and Richmond Upon Thames area. They will retreat into the nests over the next few weeks to pupate and re-emerge as adult moths, which would then lay eggs that would hatch next year.
This is the last good opportunity this year for authorities led by the Forestry Commission to reduce the population of the pest. It is a forestry pest because it strips oak trees' of their leaves, and it is a health hazard because the caterpillars shed toxic hairs which can cause unpleasant rashes and skin or eye irritations, and sometimes breathing difficulties if inhaled, in people and animals.
The Commission and its partners working to eradicate the species are therefore appealing to the public and people who are out and about among trees to report any sightings of the nests. They will follow up reports by arranging to have the nests removed and destroyed by specially trained and equipped operators, preferably while the larvae are pupating inside the nests.
Roddie Burgess, head of the Forestry Commission's Plant Health Service, said,
"Since this species first appeared in north-west and south-west London in 2006, we've had good results in reducing its population and containing it within the same general area. This has been partly due to the help we've received from the public in reporting sightings, for which we are very grateful. We need to keep up the effort if we are to eventually eradicate it, so we're once again asking local people to help us in this way.
"We urge people not to try to remove the nests themselves. They are full of toxic hairs shed by the caterpillars, which are a real health hazard, and to be most effective the work should be done by specially trained and equipped people at just the right time. Nests also need to be properly disposed of by incineration."
Suspected sightings can be reported to one of the authorities below, with as precise details as possible about the location. An Ordnance Survey grid reference is ideal; otherwise an accurate postal address with the full postcode, and/or a clear description of the tree's exact position, is helpful. Some street trees are individually labelled, but if not the code on the nearest street lamp will be useful. Digital photos sent with emailed reports can help experts to confirm the sighting.
Sightings anywhere can be reported to the Forestry Commission's Forest Research agency by telephoning 01420 22255 or by e-mail to christine.tilbury@forestry.gsi.gov.uk. Otherwise, they can be reported to the relevant Council as follows:
Sightings in Richmond Park can also be reported to the park office, 020 8948 3209; richmond@royalparks.gsi.gov.uk.
People vary in their responses to contact with the caterpillar hairs, and not everyone reacts to them. The most common problem is an itchy rash, which is unpleasant, but not dangerous.
However, occasionally people can develop breathing problems from inhaling the toxin, and people with breathing problems should seek immediate medical attention by calling an ambulance or being taken to an Accident and Emergency Department.
Otherwise, anyone concerned about their symptoms should contact NHS Direct (0845 4647; www.nhsdirect.nhs.uk) or their local family doctor for further advice.
Further information, including pictures and a tree pest advisory note, is available from www.forestresearch.gov.uk/oakprocessionarymoth and www.forestry.gov.uk/planthealth. Further public health information and frequently asked questions are available from the Health Protection Agency website www.hpa.org.uk (follow the "Topics A-Z" link) and from NHS Direct, 0845 4647, www.nhsdirect.nhs.uk.
NOTES TO EDITOR:
- Oak processionary moth (Thaumetopoea processionea) gets its name from the caterpillars' habit of moving about in long, nose-to-tail processions. It is a native of central southern Europe, but over the past 15 to 20 years breeding populations have become established as far north as The Netherlands, and individuals have been seen in southern Sweden. It is thought possible that it is surviving further north as a result of climate change leading to milder winters and fewer and less-severe late spring frosts which would kill the emerging caterpillars. The west London outbreak is almost certainly the result of trees infested with eggs being imported from the Continent for landscaping purposes.
- Nests are usually dealt with by being carefully removed from the trees into sealed bags, which are then incinerated. Residual hairs on the tree trunks are burned off with a blow-lamp to reduce the on-going risk of exposure. More than 700 nests were found and destroyed in 2007, and more than 500 last year.
- Oak processionary moth will attack a wide range of species of oak trees and oak hybrids. It will also attack other broadleaved trees, such as hornbeam, hazel, beech, sweet chestnut, birch and woody plants, although usually only where these are standing close to severely defoliated oak trees. It does not necessarily kill trees, but it would add another stress to Britain's oaks, which in some areas are already under stress from other conditions, so from woodland owners' point of view it makes sense to try to prevent its spread while this is still possible.
- The Forestry Commission has formed an Outbreak Management Team to deal with the outbreak. The team comprises representatives of Defra, the Royal Botanic Gardens, Kew, the Health Protection Agency, and Ealing, Brent, Hounslow and Richmond Upon Thames Councils.
- An amendment to the Plant Health (Forestry) Order 2005 took effect in 2009 requiring that all oak trees taller than two metres imported from EU Member States be accompanied by a plant passport confirming that the trees have been nursery grown and that they come from an area where the place of production and its immediate vicinity are free from oak processionary moth. Trees smaller than two metres may continue to be imported from affected areas because the species does not infest small trees, although a plant passport confirming that they have been inspected is still required. Meanwhile, the Forestry Commission has also asked the European Commission to draft measures to protect against further introductions by designating Great Britain, at least, as a "protected zone".
NEWS MEDIA CONTACTS:
- Forestry Commission / Forest Research - Charlton Clark, 0131 314 6500 or 07810 181067;
- Ealing Council - Helen Mathers, 020 8825 9294;
- Richmond upon Thames Council - Pete Leriche, 020 8891 7136;
- Brent Council - Peter Kendall, 020 8937 5321 / 3054;
- Hounslow Council - Jini Amarasekara, 020 8583 2186;
- Health Protection Agency in London - Tycie West or Georgina Kenyon, 020 7759 2834 / 24;
- Royal Botanic Gardens, Kew - Anna Quenby, Bronwyn Friedlander or Bryony Phillips, 020 8332 5607, pr@kew.org.