The Forestry Commission is investigating a recent outbreak of a disease affecting a number of trees on sites in Devon, Cornwall and Somerset.
The disease, caused by the pathogen Phytophthora ramorum, has been present in the UK for a number of years but, to date, has been largely associated with Rhododendron ponticum. These new finds are in Japanese larch. Many of the infected trees are not growing in close proximity to rhododendron, which raises the question of how they have become infected.
Scientists from the Forestry Commission’s Forest Research agency have isolated P. ramorum on these sites and are investigating further. As a priority they are now carrying out more extensive tests and research to determine whether P. ramorum is the main cause of the outbreak. Apart from a number of Japanese larch and Western hemlock trees, some broadleaf species (beech, birch and some oaks) growing in the same area are also infected.
Roddie Burgess, head of the Forestry Commission’s Plant Health Service, said:
“This new find could represent a significant step change in the susceptibility of our trees to this pathogen, so we are very concerned about this development. With our partners in the Food & Environment Research Agency (Fera), as well as scientists in our Forest Research agency, we are working extremely hard to learn as much as we can, as quickly as we can, about what’s happening. We can then consider what we need to do to manage the situation, building on the current programme of work to manage risks from this pathogen.
“It is important to stress at this time that much more research is needed to give us a full picture and allow us to assess what the potential implications are. Once we have done that we will share our findings with local woodland owners and managers.”
Defra announced it would provide £25 million to fund a five-year programme, which started on 1 April this year, for research, development and further disease control measures. Lord Davies, Defra Plant Health Minister, said:
“This latest find reinforces the need to press ahead with the £25 million of work we’re doing to reduce the pathogen's spread through the removal and destruction of rhododendrons from the most at-risk areas across England.
“It’s important that we continue to manage the spread of this pathogen to ensure our woodlands stay pristine and healthy so that they can be enjoyed by generations to come.”
Affected woodland sites include woodlands managed by the Forestry Commission as well as forests in private ownership.
Local forest and woodland managers who wish to be kept informed should contact the Forestry Commission’s South West England regional office at Mamhead Castle, Mamhead, Nr Exeter, Devon EX6 8HD; tel: 01626 890666; fax: 01626 891118; e-mail: fc.sweng.cons@forestry.gsi.gov.uk.
Further information about P. ramorum can be found at www.forestry.gov.uk/pramorum.
NOTES TO EDITORS:
P. ramorum was first identified in Germany in the early 1990s, and has been responsible for the deaths of millions of trees, including native American tanoaks, in western USA in recent years. The pathogen has been identified at a number of sites in Great Britain, but mostly in shrubs such as rhododendron and, more recently, the heathland plant bilberry (Vaccinium myrtillis). Despite its popular name of "sudden oak death" in the USA, Britain’s native oak species have proved to be less susceptible to it, although small numbers of other tree species, such as beech, have been infected. It is also present in 20 other European countries, although it has only been reported on trees in The Netherlands.
Fera is managing the programme of work to reduce risks from P. ramorum through the removal of infected Rhododendron ponticum from woodland, heathland and gardens. Anyone who suspects that the pathogen might be present in rhododendron on their land should contact Fera’s Plant Health Inspectorate on 01904 465625.
This press release was amended on 1 December 2009 to include the information that P. ramorum was first identified in Germany in the early 1990s.
MEDIA CONTACTS:
- Forestry Commission – Charlton Clark: 0131 314 6500
- FERA – Alison Wilson: 01904 462380 (More information about Fera can also be found at www.fera.defra.gov.uk)