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NEWS RELEASE No: 145565 APRIL 2011

Phytophthora lateralis confirmed in trees at second Scottish site

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Mature Lawson’s cypress (Chamaecyparis lawsoniana) killed by Phytophthora lateralis

The Forestry Commission is reminding owners of Lawson cypress trees to inspect them regularly following the discovery of a second site in Scotland with Phytophthora lateralis infection of the species.

The new site is Greenock Cemetery in Inverclyde, west of Glasgow. It follows the first confirmation of P. lateralis in Britain in Lawson cypress trees at Balloch Castle Country Park on Loch Lomondside in West Dunbartonshire, Scotland, in November 2010

P. lateralis, a fungus-like pathogen, had never previously been identified in Britain, and the Commission is asking owners of Lawson cypress trees to inspect them regularly and report any unexplained symptoms of dieback to its Tree Health Diagnostic & Advisory Service.

The symptomatic trees at Greenock cemetery are being felled and burned on site to limit the spread of the disease. Biosecurity measures are being put in place to minimise the risk of the pathogen being spread from the site by staff or visitors, and a spokesman for Inverclyde Council, which manages Greenock Cemetery, said,

“We’ve been working closely with the Forestry Commission to tackle this outbreak, and we would ask people to play their part in this process. We also stress that the pathogen poses no threat to the public or their pets."

John Morgan, Head of the Forestry Commission’s Plant Health Service, said,

“We’ve been on high alert for P. lateralis since it was first discovered at Balloch last year, and we feared it might turn up elsewhere. Sadly, that has proved to be the case.

“The key to containing and controlling it is constant vigilance by tree and woodland owners and managers, and reporting any unexplained dieback of Lawson cypress to us so that we can take quick action to limit the possibility of its spreading.

“Lawson cypress, especially its colourful cultivated varieties, is much enjoyed in British gardens and parks, and this disease could have serious implications for the ornamental plant industry if it becomes established here.”

Symptoms of P. lateralis infection on Lawson cypress include the foliage initially appearing a slightly lighter colour than that of healthy trees, then withering and turning reddish-brown. Also, as the infection extends from the roots and root collar up the trunk, tongues of killed inner bark become visible by their darker colour, and the entire trunk can be girdled.

Anyone concerned that their Lawson cypress trees might have the infection should contact the Forestry Commission’s Tree Health Diagnostic & Advisory Service by:
• e-mail to;
• telephone on 0131 445 2176; or
• post to Forest Research, Northern Research Station, Roslin, Midlothian EH25 9SY.

Notifications should include as precise a description of the location as possible – an Ordnance Survey or GIS reference is ideal, otherwise a full postcode is helpful. Photographs clearly showing the symptoms are also welcome to aid diagnosis.

Further information about P. lateralis, including frequently asked questions, is available from the Forestry Commission website at


  1. Staff at Greenock Cemetery, owned by Inverclyde Council, noticed unusual dieback in Lawson cypress there and notified the Forestry Commission early in March 2011. The site has more than 100 of the trees, of which 23 are showing clear signs of infection, and several more are showing early signs.
  2. P. lateralis is thought to have originated in Asia before being introduced to North America. It is the main cause of mortality in Lawson cypress (Chamaecyparis lawsoniana) in its native Oregon and California, and has caused the collapse of the Lawson cypress nursery industry in western states of the USA. It kills most Lawson cypress trees that it infects, and it can also infect other Chamaecyparis species and Pacific yew (Taxus brevifolia), a close relative of Britain’s native yew (Taxus baccata).
  3. The UK is adopting a precautionary approach to the presence of P. lateralis and is taking action under the Plant Health (Forestry) Order 2005 to eradicate or contain it by felling and destroying infected trees.

Media contacts:

  • Forestry Commission: Charlton Clark, 0131 314 6500, or Paul Munro, 0131 314 6507;
  • Inverclyde Council (for Greenock Cemetery): Matt Bingham, 01475 712920.