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Non-tree host range and diagnosis of Phytophthora ramorum (sudden oak death) in support of pest risk assessment, management and policy. - PH0193S

Host range studies: To investigate the ornamental host range (pathogenicity) of European isolates of Phytophthora ramorum from Rhododendron and Viburnum, compared to American isolates from tree and shrub species. The work will compliment work being done in parallel by the Forest Commission Research Agency (FRA) on UK forest tree and shrub hosts, including conifers. Also, to investigate the potential susceptibility of selected heathland/moorland plants to European and American isolates, e.g. native Vaccinium species (bilberry, cowberry), Arctostaphylos (bearberry), heaths and heathers.Diagnostic methods: To characterise European and American isolates to facilitate their differentiation and help determine relatedness, e.g. by using AFLP or other typing techniques. The project will also investigate PCR methods for detection and identification, including primer evaluation and detection in planta and in environmental samples such as soil and water.P. ramorum is currently the subject of UK and draft EU Emergency Legislation to prevent its introduction and spread; it is likely that the pathogen will become quarantine listed. In the USA, the pathogen is causing serious mortality of oaks and foliar and shoot diseases of other tree species and under-storey shrub genera (e.g. Arbutus, Rhododendron, Vaccinium). In Europe, isolates are only recorded on Rhododendron and Viburnum. It is not yet known whether European and American populations constitute a single cohesive species, or are varieties or subspecies that represent different environmental and plant health risks. The EU emergency legislation specifically bans the introduction and spread of non-European isolates on all known hosts, and aims to prevent movement within the community of European isolates on Rhododendron and Viburnum.Results will support the development of plant health policy, including risk management and decisions on action. The host range studies and characterisation of isolates will support pest risk analysis by determining whether European and American isolates represent different risks to UK trees due to differences in behaviour (host range) and genetic origin. The results will compliment the work being done on comparative behaviour, mating types and host susceptibility at FRA. Diagnostic methods will be used by CSL on material submitted by the PHSI, and in potential surveys around infected premises; they will also be made available to the FRA for use in their research studies and potential tree diagnoses .
1. Host range studies (ornamental and under-story shrubs)1.1. Obtain American and European isolates of P. ramorum from various hosts and select isolates for pathogenicity studies (3 EU and 3 American) from a variety of geographic & host origins.1.2. Establish standard pathogenicity tests using Rhododendron plants and European isolates of P. ramorum as a model system. 1.3. Determine the susceptibility of a wide range of potential ornamental, selected woodland shrub hosts and selected heathland plant species to European (3) and American isolates (3) using standard pathogenicity tests.1.4. Determine methods for investigating sporulation potential of susceptible heathland species1.5. Determine sporulation potential of susceptible heathland plant species2. Diagnostics2.1. Determine the specificity of CSL P. ramorum primers using a range of Phytophthora species (closely related and those occurring on P. ramorum hosts); the primers will also be screened against a representative range of American (at least 30) and European (at least 30) P. ramorum isolates.2.2. Characterise European (at least 30) and American isolates (at least 30) using molecular methods (e.g. AFLP). Isolates will be selected from a diverse range of geographical and host origins.2.3. Evaluate methods for detecting P. ramorum in plant material (leaves; green stems; bark; roots).2.4. Evaluate methods for detecting P. ramorum in environmental samples (soil/growing media; water)
Project Documents
• Final Report : Non-tree host range and diagnosis of Phytophthora ramorum (sudden oak death) in support of pest risk assessment, management and policy.   (280k)
• Annual Report : Annual report 2003/04   (49k)
Time-Scale and Cost
From: 2002

To: 2004

Cost: £76,130
Contractor / Funded Organisations
Central Science Laboratory
Alien Species              
Disease Control              
Fields of Study
Plant Health