Forestry, health and local authorities today launched a joint plan to try to eradicate from London a recently arrived moth that threatens Britain's oak trees and human health.
And they want the public to help by reporting sightings of the caterpillars (the moth's larval stage) or its nests. Oak processionary moth (Thaumetopoea processionea) - a native of southern and central Europe - turned up on trees in west and south-west London last summer, and has begun breeding in oak trees in a number of locations there, including Kew Gardens.
The caterpillars - the larval stage of the moth's life cycle - pose twin problems. They severely defoliate oak trees by feeding on the leaves, and their tiny hairs are not only sharp and barbed, but also contain a toxin that can cause irritation and allergic reactions in people, even after the hairs have been shed by the caterpillars.
Contact with the toxin most commonly causes intensely itchy skin rashes, but can also cause sore throats, eye problems and breathing difficulties. These can happen because people touch the caterpillars, and it is also possible for the wind to blow the shed hairs so that they come into contact with people’s skin or eyes, or are inhaled.
Now the Forestry Commission, working with Defra  the Health Protection Agency London, and Ealing and Richmond Councils, has drawn up an action plan. This will aim to determine the geographical extent of the infestation with a view to developing a strategy to reduce or eliminate young larvae (caterpillars) soon after the eggs hatch next spring, before the moth spreads out of London and becomes permanently established in Britain.
Teams with special training and equipment - including protective suits - will spend the next few months finding the moths' nests, using pheromones (an artificial lure that attracts male moths) to monitor flying moths, and surveying for eggs laid on branches.
Roddie Burgess, the Forestry Commission's head of plant health, said,
"We believe we still have a good chance to get rid of the oak processionary moth while it is confined to this part of London and before it spreads any further.
"If it is allowed to get established it will cause problems not only to Britain's much-loved oak trees - and possibly to other tree species that it can also attack - but also to human health.