Phytophthora ramorum (P. ramorum) is a fungus-like pathogen of plants that is causing extensive damage and mortality to trees and other plants in parts of the United Kingdom. It has also been found in a number of European countries, but mostly on plants and shrubs, especially rhododendron, viburnum and camellia, and has caused significant damage and mortality to many trees and other plants in parts of the USA.
However, few trees in the UK were affected until 2009, when P. ramorum was found infecting and killing large numbers of Japanese larch trees in South West England. Then in 2010 it was found on Japanese larches in Wales, Northern Ireland and the Republic of Ireland.
This sudden change in the pathogen’s behaviour was the first time in the world that P. ramorum had infected and sporulated (reproduced) on large numbers of a commercially important conifer tree species. It was also an unexpected setback to efforts to tackle ramorum disease.
We and our partners have moved quickly to respond to this development. Full details about the pathogen and what’s being done to research it, minimise its impact, and support affected woodland owners are available at the links on this page.
Latest
P. ramorum infection of larch trees has now been confirmed at sites in Lancashire and Cumbria in North-West England, the Peak District of Derbyshire in central England, and in Scotland on the island of Mull, the Craignish Peninsula and Galloway.
Update report
We have published a one-stop-shop 'update' report in accessible language summarising all aspects of the P. ramorum outbreak in larch. It summarises a range of topics including the current scientific knowledge, symptoms and treament, its impact on the timber market, and advice and assistance to woodland owners.
Reporting suspected cases
Suspected cases of ramorum disease on larch trees can be reported to us at the following contact points:
- Scotland - ddas.nrs@forestry.gsi.gov.uk; tel. 0131 445 2176;
- England - plant_health_england@forestry.gsi.gov.uk (please note the underscores, i.e. plant_health_england); tel. 0117 372 1070;
- Wales - bww.ts@forestry.gsi.gov.uk; tel. 0300 068 0300.
Key documents
Among the key documents and guidance available within these pages are:
Symptoms guide. Larch can suffer from a number of diseases, not all all of them serious, so before reporting a suspected case, check the symptoms of ramorum disease in our symptoms guide.
Replanting advice. We do not recommend restocking (replanting) affected sites with larch or other species that are susceptible to P. ramorum, so this guide sets out options for the woodland owner.
Biosecurity precautions. This guide provides advice on precautions to take when visiting or working in an infected woodland to limit the risk of accidentally spreading the disease on clothes, tools or vehicles etc.
P. ramorum found on Sitka spruce
The Forest Service of the Irish Department of Agriculture, Fisheries & Food has reported the first finding of a Sitka spruce (Picea sitchensis) in the wild infected with Phytophthora ramorum. Sitka spruce is the most widely grown timber-producing tree species in the United Kingdom. For further information see the section on P. ramorum on Sitka spruce in the update report.
Plant health inspections
Inspections of trees and woodland by Forestry Commission plant health inspectors play an important role in our efforts to manage outbreaks of ramorum disease. Our Guidance for Plant Health Inspectors can help you understand what to expect if an inspector needs to visit your premises.
Last updated 2 August 2011
