Oak processionary moth

 

Oak Processionary Moth (Thaumetopoea processionea) a native of southern and central Europe has been found in trees in the west and south west of London. The moth first appeared in Great Britain in summer 2006 and has begun to breed in oak trees in several locations.

In June 2007 in response to reports of tree damage the Forestry Commission launched a Contingency Plan and produced a Pest Alert Poster (updated and re-issued in May 2008).

The caterpillars - the larval stage of the moth's life cycle, pose two problems.  They severely defoliate oak trees by feeding on the leaves and, from the 3rd instar, have tiny hairs which are sharp, barbed and contain a toxin that can cause irritation and allergic reactions.  Further information including Q&A's can be found on the Forest Research website.

The Forestry Commission, working with Defra, Royal Botanic Gardens Kew, the Health Protection Agency London and Ealing and Richmond Borough Councils has formed an Outbreak Management Team and agreed an Action Plan which was put in place in June 2007.   The aim of the action plan was to determine the extent of the infestation with a view to developing a strategy to reduce or eliminate the caterpillars soon after the eggs hatch in spring 2008 before the moth spreads out of London and becomes permanently established in Britain.

To view the Minutes of the first meeting of the Outbreak Management Team held on 13th June 2007.

Over the summer of 2007, as a result of surveys carried out in the London Boroughs of Brent, Ealing and Richmond, around 700 nests were found and destroyed.  Details of the action taken is contained in a Survey Report.

As a result of these findings a formal request has been made to the European Commission to consider designating Great Britain as an EU 'protected zone' with measures to prevent further accidental introductions which we consider necessary if our eradication attempts are to succeed.  Pending a final Decision, the Forestry Commission has put in place temporary emergency measures by amending the Plant Health (Forestry) Order 2005 (SI2008/644).  This came into force on 31 March and requires that all Oak trees coming from another Member State must have a plant passport confirming that the plants have been grown in a nursery where the Moth is not present and which has been free of symptoms for the last complete growing season.

To view the Minutes of the second meeting of the Outbreak Management Team held on 7 February 2008.

We have now begun surveying the affected parts of London for nests again (April 2008) and will require any emerging larvae to be treated with insecticide. Guidance on surveying and treatment of larvae has been published by the Tree Health Division of Forest Research.  Pheromone traps will be sited across London in the summer when any adults will be active.  (Updated 12 May 2008)