Sarah Green
Sarah obtained her PhD in plant pathology in 1995 from Lincoln University, New Zealand and subsequently worked as a plant pathologist in Canada. Since 2001 Sarah has been the senior forest pathologist leading the pathology group at Forest Research’s Northern Research Station, conducting research into a range of tree diseases and disorders including birch dieback, horse chestnut bleeding canker and drought stress. Currently she manages Forest Research’s Programme on Understanding Biotic Threats to Resilience and is the Principal Investigator on the interdisciplinary PHYTO-THREATS LWEC Phase 3 project which addresses global threats from Phytophthora species. Her main research interests are distribution, detection methods, biology and evolutionary genetics of forest pathogens, with a particular recent focus on emerging Phytophthora diseases.
Projects
This project will carry out a targeted survey of Caledonian pine in Scotland to assess extent and incidence of symptoms and to collect samples; compare and identify to species level isolates of potential causal agents collected from native Scots pine and determine their phylogenetic placement and genetic diversity; develop an effective inoculation method through studies of the infection process on needles and woody tissues of Scots pine, and; determine the pathogenicity of the causal agent(s) on Scottish provenances of Scots pine.
This project was selected for funding from the Project Call: “Enhancing preparedness against pests and diseases: plugging evidence gaps for Scotland”.
PHC2021/08 will implement an Action Research approach, delivered through workshops co-designed with network organisations, to better understand current plant biosecurity risks in several sectors, to identify their plant health knowledge needs, and to begin to embed biosecurity training within existing organisations, programmes and processes.
The outcomes of the project will be:
• An enhanced understanding of the knowledge and training needs of different sectors and the identification of biosecurity actions that will fill some of the gaps identified by PHC2019/04/05/06
• The identification of further training needs and potential approaches to address the problems identified
• A legacy of close working relationships between the PHC and several network organisations, key to future plant biosecurity research or training delivery activities
Drawing upon and summarise existing literature, in addition to engagement with experts and practitioners with knowledge of existing sectoral practices in Scotland, UK and internationally, as well as gap analysis, the project will generate a better understanding of the rationale for taking precautions and an improved evidence base with which to justify taking action, answering four main questions:
• What are the current barriers to adopting precautionary measures?
• How can barriers be reduced?
• What are the limitations of the current risk assessment process?, and
• What are the priority areas for action and further research?
This work will examine and define the extent to which current UK and Scottish regulations and voluntary schemes control the way growing medium constituents must be treated prior to their inclusion in growing media, to generate an understanding around mitigating risks of spread of plant pathogens. Workshops with stakeholders will improve understanding of current practices and perceptions of alternative ‘best practice’ options for nurseries managing waste materials and for biosecurity risks of using reduced peat and peat-free growing media. A concurrent diagnostic study will identify Phytophthora species present in waste heaps from nurseries located in Scotland and the potential for these pathogens to spread into healthy plant stock either aerially or via water run-off and soil transfer.
Findings will be combined with a comprehensive desk-based study and feed into follow-up workshops on the development and introduction of ‘best practice’ guidance on the most appropriate and safest ways to manage waste growing media and plant material, to be built into the Plant Health Management Standard.
Impact: Determine the main barriers to ensuring that future planting for environmental restoration and conservation will minimise plant health risks.
Impact: Provide Scottish Government policy with an assessment of the major biosecurity pitfalls and opportunities arising from large-scale landscaping plantings.
Impact: This project will enable policy to identify and prioritise plant biosecurity vulnerabilities from non-specialist and online horticultural sales.
Impact: Timely management and prioritisation of policy to manage P. ramorum and facilitate early forecasting of other Phytophthora outbreaks.
Impact: Add to the evidence base underpinning public and sector-facing biosecurity campaigns and improve disease management and restrict spread of the disease.
Publications
Understanding a new health threat to Caledonian Scots pine (Pinus sylvestris)
This project was initiated in response to a new health threat to Scots pine manifesting itself in the form of multiple blackened cankers and dieback of shoots and branches, particularly in the lower crown. Scots pine is regarded as iconic in Scotland for a range of ecological, cultural and economic reasons. Therefore, it is a research priority to gain an understanding of the extent and causes of the canker disease for better protection of this species in the future.
Identifying the plant health risks associated with plant waste disposal and peat-free growing media and developing best practice guidance for waste disposal and composting across sectors
This research focussed on two areas of biosecurity that provide significant risk to plant businesses and the wider environment in Scotland, i) plant waste management, and ii) the constituents of reduced-peat and peat-free growing media.
The potential of ecological and epidemiological models to inform assessment and mitigation of biosecurity risks arising from large scale planting
Large scale planting projects linked to infra-structure such as transport networks and major housing projects or to planting for environmental benefits (e.g., urban greening, woodland restoration) pose high biosecurity risks due to the high number and types of plants involved. This report focusses on whether and how ecological and epidemiological model frameworks can inform assessment and mitigation of biosecurity risks from large scale planting using a combination of literature review and stakeholder engagement. The project aimed to identify priority steps to develop more useful models and tools for assessing biosecurity risks from planting in the future.
Metabarcoding analysis of Phytophthora diversity in spore traps and implications for disease forecasting in the P. ramorum management zone
Surveillance and monitoring of airborne pathogens is a key tool in the management of healthy forests and controlling disease outbreaks. A Scottish Forestry-funded project was carried out in autumn 2019 to validate different spore-trapping techniques for monitoring airborne P. ramorum inoculum using a species-specific qPCR assay. This project aimed to add further value to the Scottish Forestry project by investigating the suitability of DNA metabarcoding for screening spore trap samples for P. ramorum and other Phytophthora species, seeking early data for aerially dispersed Phytophthora species that may become problematic in UK forests. The study highlighted the value of both monitoring P. ramorum dispersal and detecting other Phytophthora species, to predict and understand changes in disease severity in UK tree host species. Recommendations included that the use of both rain and wind-borne inoculum capture methods might be advantageous due to the variety of weather conditions under which inoculum can disperse. Lineage testing in Southwest Scotland should be carried out to look at the prevalence of lineage EU1 in the EU2 area and to monitor for presence of North American lineages. Development of a new DNA barcode more specific to Phytophthora would be beneficial.