Phytophthora austrocedrae organism found in rare U.K. junipers; disease almost unknown in Britain until recently, and scientists expect it to spread, affect other species

Wendy Lisney

EDINBURGH, U.K. , February 9, 2012 (press release) – A damaging plant disease that was until recently almost unknown in Britain has been confirmed in rare native juniper bushes at the Moor House-Upper Teesdale National Nature Reserve in the North Pennines of England.

The disease is caused by Phytophthora austrocedrae, a fungus-like organism that infects the plant through the root system and causes the foliage to decline and eventually die.

Juniper is a native conifer and a member of the Cypress (Cupressaceae) family of plants. P. austrocedrae infection was only confirmed in the UK last year on other trees from this family, at two sites in Scotland.

The source of the infection is unknown: P. austrocedrae is difficult to identify because it is rare, and there is only limited information available about it. However, the Forestry Commission scientists who identified it believe it can be transmitted in ground water, infected plant material and contaminated soil, making further spread very difficult to prevent.

It is especially serious because juniper is quite rare in the UK. The Teesdale juniper population is the second largest in the UK and is protected as part of a Special Area of Conservation (SAC).

Scientists from the Forestry Commission’s Forest Research agency are undertaking further studies to confirm how damaging it might be on juniper, Lawson cypress and other potential tree hosts.

Natural England, which manages the site, is working with the Forestry Commission and the Food & Environment Research Agency (Fera) to survey the extent of the infection and consider how it might best be contained, as well as putting biosecurity measures in place for anyone working on the site

A survey of other areas where juniper is widely distributed will be co-ordinated by Fera to determine whether the disease is present elsewhere. The results, along with the outcome from an imminent consultation by Fera, will help to determine a longer-term strategy. Partner organisations across the UK have been alerted and information will continue to be shared.

Control plans will be developed in discussion with local landowners, farmers and other stakeholders in the area, and a meeting organised as soon as the three organisations have more information and draft proposals to discuss.

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

“Juniper habitat is rare, and a number of people and organisations are working hard to protect and restore it. It is therefore especially disappointing to learn that this very damaging disease has affected such an important site in England.

“We join our partners in Natural England and Fera in urging everyone who works at or visits this site to co-operate with the measures we are developing to prevent accidental spread of the disease. By taking these precautions we stand our best chance of preventing the disease spreading to other places.”

Chris McCarty, senior reserve manager from Natural England, added,

“This is a serious outbreak for juniper trees in Upper Teesdale. Now the disease has been identified, we are working with the landowner, Fera and the Forestry Commission to put plans in place to contain what we hope is a single outbreak on juniper. We will need the help of neighbouring landowners, farmers and organisations in drawing up our plans and assisting with the measures to tackle it.”

Martin Ward, Head of Policy at Fera, said,

“This is a significant finding, the first of its type in Europe, and we are working closely with our partners to tackle the situation in Upper Teesdale. We also need to see whether the pathogen is present elsewhere, because this will influence our longer-term strategy. This additional survey work, together with the consultation that we plan to carry out, will be important in moving forward.”

Further information is available from www.forestry.gov.uk/paustrocedrae.

•The Government recently launched the Tree Health & Plant Biosecurity Action Plan to ensure that the UK's defences against tree pests and diseases are as robust as possible.

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1. P. austrocedrae has mostly been associated with the decline of Chilean cedars (Austrocedrus chilensis) in Patagonia, South America, and gets its name from this association.

2. Juniper (Juniperus communis) is one of only three conifer species native to Britain, the others being Scots pine and common yew. It is very rare, its area having declined to only about 400 hectares (1000 acres) in Britain in woodlands greater than 2ha. 75 per cent of juniper woodland is in Scotland. Juniper is a key food plant for a wide range of invertebrates and birds, and it has a unique and specialised group of associated insects, fungi and lichens.

3. Phytophthora, from the Greek for “plant destroyer”, is the name of a large group of more than 100 destructive pathogens of plants. A number of Phytophthora species that attack trees have been discovered in Britain for the first time in recent years. Their increased presence in the UK is often associated with the growing international trade in live plants. For further information visit www.forestry.gov.uk/phytophthora.

4. Special Areas of Conservation are areas which have been given special protection under the European Union’s Habitats Directive. They provide increased protection to a variety of wild animals, plants and habitats and are a vital part of global efforts to conserve the world’s biodiversity.

5. Natural England is the Government’s independent adviser on the natural environment. Its work focuses on enhancing England’s wildlife and landscapes and maximising the benefits they bring to the public to:

• establish and care for England’s main wildlife and geological sites, ensuring that more than 4000 National Nature Reserves and Sites of Special Scientific Interest (SSSIs) are looked after and improved;
• ensure that England’s landscapes are effectively protected, designating England’s National Parks and Areas of Outstanding Natural Beauty (AONBs), and advising widely on their conservation;
• run Environmental Stewardship and other 'green' farming schemes that deliver more than £400 million a year to farmers and landowners, enabling them to enhance the natural environment across two thirds of England’s farmland;
• fund, manage and provide scientific expertise for hundreds of conservation projects each year, improving the prospects for thousands of England’s species and habitats; and
• promote access to the wider countryside, helping to establish National Trails and coastal trails and ensuring that the public can enjoy and benefit from them. Visit www.naturalengland.org.uk for further information

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