Reproduced below is the Forestry Commission Scotland’s lastest update on P. ramorum on Larch.
22 MAY 2012 NEWS RELEASE No: 15472
Landowners urged to help in fight against tree killer
Landowners and woodland managers in the west of Scotland are being urged to keep their eyes open over the next few weeks for early signs of infection in larch.
Forestry Commission Scotland is enlisting the help of landowners in the latest move in the effort to contain the spread of Phytophthora ramorum (P. ramorum), and limit the damage to valuable woodlands.
Hugh Clayden, the Commission’s Tree Health Policy Adviser, said;
“Until 2009 this fungus-like disease affected shrubs like Rhododendron ponticum, viburnum and camellias, but in that year it was seen to have ‘jumped’ to Japanese larch in south west England. Infected larch crops have since been found in all four UK countries as well as the Republic of Ireland.
“As the disease has the capacity to spread very quickly, infecting (and killing) trees, affected crops need to be felled or killed as soon as possible to prevent wider spread. It has the potential to devastate larch woodland and cause substantial landscape, biodiversity and economic damage.
“With last autumn’s persistent wet weather and high winds, followed by a mild winter, very significant spread of the disease is possible and this has been confirmed in Galloway where well in excess of 100 hectares of new infection have already been detected.
“Containing this disease is all about early detection and rapid, subsequent action – and for that to be effective we need people to let us know as soon as they suspect they might have an infection.”
Early identification relies on constant vigilance. The sooner infected stands are identified, the quicker they can be felled to reduce the chance of further spore production and subsequent spread to other woodlands and host plants.
Symptoms when externally viewing stands of larch include
• Dead and partially flushed trees present in groups, patches or distributed throughout stand.
• Crown and branch dieback likely to be present with distinctive yellowing or ginger colour when branches are girdled.
Additional symptoms within stands of mature larch include
• Individual or many branches with partial or complete dieback in crown.
• Epicormic growth protruding through dead branches (sometimes extending down stem below dead crown).
• Profuse resin bleeds on main stem (at crown level) and branches (may only be visible with binoculars).
The Commission will be carrying out helicopter surveys along the west coast in June but are advising woodland managers not to rely on these to provide notification of the presence of infection. All woodland owners and managers have a role to play in trying to contain the rapid spread of this highly damaging disease.
If you suspect that you have located a stand of larch infected with P. ramorum, please report it without delay to firstname.lastname@example.org .
Owners or managers of individual garden, parkland, street or amenity trees who think their trees might be infected should contact the Forest Research Tree Health Diagnostic Advisory Service at www.forestry.gov.uk/fr/ddas
For the latest information on larch dieback caused by Phytophthora ramorum please see www.forestry.gov.uk/pramorum
Notes for Editors:
1) Forestry Commission Scotland serves as part of the Scottish Government’s Environment & Forestry Directorate.
2) P. ramorum was first found infecting and killing Japanese larch trees in south west England in 2009. In 2010 it was found on Japanese larches in Wales, Northern Ireland and the Republic of Ireland, and since late 2010 onwards it has been confirmed at locations on the Craignish peninsula, the island of Mull, Islay and Galloway.
3) The most recent confirmed outbreaks of P. ramorum have been at the National Trust for Scotland’s Arduaine Garden and at Carradale in West Argyll.
4) Media enquiries to Paul Munro, Forestry Commission Scotland press office, 0131 314 6507