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Ramorum disease

Regulations are in place to prevent spread of Phytophthora ramorum in Scotland to protect larch. Our tree health team conduct national scale aerial surveillance to monitor larch trees for new symptoms every year. 

Published: 22 Feb 2025

Topic: Manage forests

Is ramorum disease found in Scotland?

Ramorum disease is caused by a pathogenic fungal-like water mould called Phytophthora ramorum. 

It was first found in Scottish plant nurseries in 2002 and in gardens and parks in 2007. The first infection on Scottish larch trees was confirmed in 2010. 

Did you know?

Ramorum disease can be spread in mud and needles stuck to footwear and machines, vehicles, bicycle or buggy tyres. 

Follow ‘Keep it Clean’ checks to help stop the spread of ramorum disease when you visit forests and woodlands.

How does ramorum disease affect trees?

The signs and symptoms of ramorum disease vary with host species. 

The Observatree field guide to identifying Phytophthora ramorum describes symptoms on several different hosts. 

Field Identification Guide - Phytophthora ramorum (Observatree website)

If you own or manage a woodland with larch or rhododendron, you should check these plants for symptoms of ramorum disease.

Important: Help stop the spread

Woodland owners and managers! Follow our biosecurity guidance to help stop the introduction and spread of Phytophthora ramorum.

Consider our guidance on preventative actions you can take to help stop the introduction and spread of tree pests and diseases.

Report suspected sightings of ramorum disease

Report suspicious symptoms on any tree in Scotland to TreeAlert using the general enquiry webform.

Use TreeAlert (Forest Research website)

The web form asks for:

  • your contact details
  • the location of the sighting
  • clear photographs of the affected tree(s) in context and the symptoms

For more information on what to include in your report, visit the ‘TreeAlert - what to do page’.

What do you need to make your report (Forest Research website)

Once you submit your report, diagnosticians at Forest Research will review it. They may contact you to request additional details.

Any suspected findings of regulated pests or pathogens, such as Phytophthora ramorum, will be sent to our Tree Health Officers for follow-up.

Phytophthora manual with sections about symptoms and biosecurity (Forest Research website)
 

Action to limit risks posed by ramorum disease

We conduct aerial surveillance every year to identify new symptoms of ramorum disease across Scotland. 

Any newly suspected locations are followed up with ground surveys to collect samples for molecular diagnosis performed by Forest Research. 

A large proportion of larch in Scotland remains uninfected. Control actions remain necessary to slow down the rate, extent, and severity of disease spread to protect these trees.

Our action plan

In the winter of 2020/21, stakeholders from the forestry sector were invited to take part in a formal review of the 'Phytophthora ramorum on larch Action Plan'. 

We published the revised action plan in June 2021. Management for ramorum disease is conducted in three different Zones. 

Scottish Forestry Phytophthora ramorum Action Plan

Further information about the rationale and implementation of measures outlined in the Action Plan are detailed in our Question and Answer document. 

Frequently asked questions: Phytophthora ramorum management policy

Priority Action Zone (PAZ)

The PAZ is the area where actions will have the greatest impact on controlling spread of ramorum disease. To date, outbreaks in the PAZ have been limited. 

Control efforts here have:

  • successfully eradicated infections on larch
  • safeguarded surrounding areas 
  • slowed disease spread

We are committed to prioritising surveys and the issue of Statutory Plant Health Notices (SPHNs) in the PAZ. 

Important: Felling of infected trees

Felling of infected trees under SPHN is usually required by the end of February in the year following detection. 

Risk Reduction Zone (RRZ)

The RRZ is the area where the spread and scale of infection are beyond what can be controlled locally. The main aim is to reduce the risk of ramorum disease to the sector.

To achieve this, SPHNs continue to be issued in the RRZ but with longer deadlines for compliance compared to the PAZ. 

This ensures consistency of control efforts between land owners to reduce build up of the disease in the environment.

Management Zone (MZ)

An area in south-west Scotland was at the heart of a major surge of ramorum disease on larch in 2013. 

The Plant Health (Forestry) (Phytophthora ramorum Management Zone) Order 2014 designated this area as a Management Zone.

Plant Health (Forestry) (Phytophthora ramorum Management Zone) Order 2014 (legislation.gov.uk website)

Within this Zone, the disease was too advanced to stop its spread within the area. Larch is being removed according to timelines given in existing Management Plans.

SPHNs for P. ramorum are generally not issued inside the Management Zone. This allows the phased removal of larch, as timber is harvested and processed.

Statutory Plant Health Notices (SPHNs)

Restrictions apply in Scotland to manage ramorum disease.

To prevent introduction and slow the spread of Phytophthora ramorum, SPHNs require felling of infected larch and all larch within a buffer zone (usually 250 m).  

The disease can also infect rhododendron species which then act as a source for further infection. 

Where ramorum disease is confirmed in rhododendrons, SPHNs will be issued requiring removal of all infected rhododendron and all rhododendron plants within a 2 metre buffer zone.

Specific biosecurity measures are required by SPHNs to prevent the transport, introduction and spread of ramorum disease from infected sites. 

Biosecurity requirements remain active for three years following the date of host removal under SPHN. 

This includes:

  • cleaning machinery, tools and footwear
  • limiting vehicular access
  • providing signage


SPHN biosecurity requirements

Details of SPHN biosecurity requirements are provided in this guide: 

Biosecurity on sites served with a Statutory Plant Health Notice for Phytophthora ramorum on larch

You can also read research funded by the Plant Health Centre (Scotland’s Centre of Expertise).

Assessing spread of Phytophthoras in Scottish forests by recreational and harvesting activities using comparative qPCR and metabarcoding techniques (Plant Health Centre website)

Posters showing actions forestry workers and the public can take to help stop the spread of ramorum disease are available for download in two different sizes:

Forest workers

Phytophthora ramorum disease biosecurity poster for forestry workers - A3 size

Phytophthora ramorum disease biosecurity poster for forestry workers - A4 size
 

Public

Phytophthora ramorum disease biosecurity poster for the public - A3 size

Phytophthora ramorum disease biosecurity poster for the public - A4 size

Recommendations for restocking sites affected by ramorum disease with both conifer and broadleaf species are provided in this guidance document.

Advice on replanting sites affected by Phytophthora ramorum

Conditional financial support for landowners

We offer conditional financial support to landowners issued with an SPHN for ramorum disease.

Eligibility criteria for the Tree Health grant are available on the Rural Payments and Services website.

Visit our Forestry Grant Scheme pages to find out more.

Wood movement and processing licences

Movement and processing licences in Scotland are issued by the Forestry Commission on behalf of Scottish Forestry.

Application forms are available on the Forest Research website.

Licences to move and process wood from trees with ramorum disease (Forest Research site)

Please contact the Forestry Commission plant health team with any enquiries or support needs relating to movement or processing licences.

Contact Forestry Commission plant health team (email)

You must apply for a movement licence to:

  • remove wood from a site issued with an SPHN
  • to move larch material from within the Management Zone to any site outside it

Wood can only go to a facility that holds a processing licence to handle it, both for:

  • wood from SPHN sites
  • wood moving from within the Management Zone to a site outside it

Report suspected ramorum disease

To report suspected ramorum disease, use the TreeAlert service at Forest Research.

This online platform allows you to submit detailed observations, including photos and location, helping quicker diagnosis and action.

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