The impacts of introduced plant pests and diseases have been substantial in recent times. With a changing climate and many known pests on the horizon, plant health impacts on biodiversity are expected to grow further in the years ahead. Thus, considering the nature of plant health threats to the natural environment and embedding mitigating actions into biodiversity strategies is of increasing importance.

Pathogens from the genus Phytophthora pose some of the greatest threats to tree health and are likely to become increasingly prevalent in the UK as the climate becomes warmer and wetter. This project added new data based on a DNA metabarcoding approach to determine the Phytophthora species diversity in soil samples and sampled material from timber harvesting operations alongside those of recreational activities.

This project has developed a systems approach, in the context of plant health biosecurity risks in the retail, infrastructure landscaping and planting in the natural environment, to facilitate further understanding of key organisations and identify general and specific leverage points at which interventions could have a significant effect on the system.

The Bronze Birch Borer (BBB, Agrilus anxius) is a major threat to birch trees. This project had co-funding from Scottish Forestry and NatureScot and undertook evidence gathering to assess the threat BBB poses to Scotland, inform risk assessment, surveillance and contingency planning, and identify key risks and knowledge gaps.

Insecticides are commonly used in Scottish agricultural, horticultural, forestry production, and for amenity and natural environment management purposes.  Over the last 10 years, approximately 50% of UK insecticide active substances have been withdrawn due to increasing concern over human health and environmental impacts.  Some of these losses will be mitigated by using alternatives but their practicality and cost under Scottish conditions is unknown.  This project analysed current crop production patterns and insecticide use in combination with how likely different insecticides are to be withdrawn and provided stakeholder views on the impacts of any such losses on their industry, including other control methods that may be adopted.

The Plant Health Centre works with Scottish Government, public bodies and stakeholders to provide scientific evidence to help them make important decisions about pests and pathogens that threaten Scotland the most.  Over the past 12 months we have delivered a consistent programme of stakeholder engagement and project commissioning, which are detailed in our annual report. 

This research investigated plant biosecurity risks from site visitors, tools & equipment, and large machinery. In addition to reviewing published guidance, UK businesses and organisations were engaged via questionnaires and interviews to explore how these aspects of biosecurity are understood and what procedures may be in place to address them.

This project was commissioned to implement a selection of the recommendations made in the PHC stakeholder engagement strategy and communication plan. The team developed strategies to manage time and resources of the Plant Health Centre more efficiently regarding communication of outputs, general information on activities, aims and current issues related to plant health.

If introduced to the UK, the insect-vectored, bacterial plant pathogen Xylella fastidiosa could be a serious threat to trees and other plants. There is a lack of knowledge about the ecology and distributions of Xylella vectors in Scotland and the potential effects of this on any outbreak of the disease, which this project aimed to address.

This report is the output of a call-down project that assesses the type of plant health problems in Scotland that GE could address, with potential benefits, barriers to deployment and dis-benefits noted.

PHC commissioned an assessment of large-scale biosecurity risks with a focus on three areas of concern:

1. non-specialist and online horticulture sales;
2. landscaping and infrastructure;
3. planting for environmental benefits.

An additional area was the potential for modelling to support decision making across these areas of concern.  This policy report summaries each report and highlights the key findings and suggested actions.  

This project focused on an initial exploration of tree and plant biosecurity risks to Scotland arising from large-scale movement of plants via non-specialist (those for which plants are not their primary product type, e.g., supermarkets, DIY and lifestyle stores) and online plant retailers. By better understanding the characteristics of these retailer types, the plant health behaviours they undertake, and the challenges they face, potential avenues were offered for greater engagement and collaboration on biosecurity with this important, but understudied and hard to reach sector.

Planting for large-scale landscaping and infrastructure can typically involve tens of thousands of individual plants, potentially threatening plant health in Scotland due to the biosecurity risks of imports and widespread planting of infested or diseased plants. This project aimed to understand the extent and means to mitigate against such plant biosecurity risks with a focus on mapping the pathways from plant specification through to planting and establishment and highlight different biosecurity awareness for actors, in decision-making and procurement processes.

This report features five case studies from across Scotland and examines risks associated with large scale tree planting schemes, levels of awareness around pests and diseases, and how the decisions and actions of those involved can serve to reduce or exacerbate pest and disease related threats and long-term tree health. Each case study was unique in respect to their combination of location, site conditions, ownership, management objectives, species choice, supply chains and management activities. By highlighting best practice and lessons learned, it was hoped to ensure that future planting schemes can be successful and, importantly, reduce the likelihood of pests and diseases being introduced and spread into the wider environment.

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.

Emerald Ash Borer (EAB) has become a significant threat to ash trees in several countries (including USA and Russia) but is not yet present in the UK. We quantified climate and ecological factors affecting EAB suitability using native range data and conclude that southern England is a highly suitable habitat for EAB. Although currently less favourable, we project that Scotland will become increasingly suitable for EAB under climate change. Thus, EAB could threaten Scotland via trade with areas where it is present or, through spread from populations if established in England or Western Europe. Rapid spread of EAB has been observed in its US invasion. We therefore recommend further study and vigilance against EAB introductions into the UK.

The aim of this project was to develop an operational communication plan from existing stakeholder engagement principles, communication theories and knowledge banks, identifying and summarising actions for the PHC.

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.

Chemical forms of plant protection are widely used in Scottish agricultural, horticultural and forestry production plus for amenity and natural environment management purposes.  The availability and use of active substances in pesticides are closely regulated and increasing concern over human health and environmental impacts has led to a greater likelihood that some existing approvals will be withdrawn and/or that approvals for new products will not be granted.  Potential impacts from withdrawal of these pesticides are of policy interest and this summary report builds on the data and results from project PHC2018/15 (Potential impacts arising from pesticide withdrawals to Scotland’s plant health) and uses case studies to understand the likely magnitude and distribution of potential impacts and how they may be mitigated. 

The use of pesticides to manage plant pests and diseases is a key management intervention across plant health sectors, particularly in agriculture, horticulture and commercial forestry production. Pesticide withdrawals through legislation, coupled with resistance development and their impact on plant health, have emerged as key concerns for Scottish plant health stakeholders.  This project quantifies the impacts on Scottish plant health that will arise from pesticide withdrawal scenarios and sets this in the context and time frame of alternative management tools. 

This project constructed a modelling framework which combined epidemiological and economic modelling.  The modelling framework was used to study predictions of spread and economic impact of pests which are not currently in the UK, including Xylella fastidiosa, Candidatus Liberibacter solanacearum (Zebra chip) and Ips typographus (Eight toothed Spruce Bark Beetle). 

Impact:  A web/desktop application is available to the PHC and Scottish Government to analyse the effects of climate change on the spread and economic impact of new threats. 

This project investigated whether modelling could aid preparation for a potential bark beetle and wood borer invasion of Scotland. This was achieved by: (i) reviewing suitability of modelling results and frameworks in literature; (ii) recommendations on how these could be rapidly adapted for Scottish and UK plant health context and (iii) case study on Emerald ash borer to exemplify approach.

This project has expanded the PHC online Resource Bank for plant health threats to the Natural Environment sector in Scotland to include information sources for the remaining three sectors (Forestry, Agriculture and Horticulture). Information sources for Forestry, Agriculture and Horticulture were compiled and evaluated, and a Knowledge Bank relevant to each sector is now online at the PHC website, creating a comprehensive and unique signposting resource for plant health information with relevance to Scotland.

Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from Oak Processionary Moth to Scotland.

Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from the Eastern spruce budworm (Choristoneura fumiferana), Western spruce budworm (C. freeman) and  Black headed budworm (Acleris gloverana and A. variana) to Scotland

Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from Emerald ash borer and Bronze birch borer to Scotland  

Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from the larger eight toothed spruce bark beetle (Ips typographus) to Scotland

Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from longhorn beetles to Scotland

Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from Phytophthora ramorum to Scotland

Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from Xylella fastidiosa to Scotland  

The aim of the project PHC2018/11 was to compile a resource to be embedded within the Scottish Plant Health Centre (PHC) website, with the following three main purposes: 1) To direct users to existing, comprehensive and reliable plant health information resources; 2) To provide information on selected plant health threats to the natural environment, particularly invasive non-native species; and 3) To direct users to appropriate government agencies and resources and advise users on steps to take should a suspected statutory pest or disease be encountered.

Webpages have been developed which provide the following:

1) a listing of the first most pressing plant health threats to the natural environment in Scotland;

2) a user-friendly web template, populated with links to information about these major threats and other topics relevant to plant health in the Scottish natural environment; and

3) summary pages providing guidance on biosecurity and control of diseases in this sector, for which other resources were not easily available.

The aim of the project was to review existing websites and smartphone apps currently available and applied in the plant health sector and to assemble a detailed overview covering the following points:

• What options are available in terms of mobile software applications for plant health?
• What is their primary purpose?
• Who is the target audience (growers, plant health professionals, citizen science, …)?
• Which plant health sectors do they cover?
• Are they reliable and accurate?
• Is information submitted to a central database? If so, how is this information used?
• Could they be used globally, or are they limited to certain geographic regions?

Heritage gardens play an important role in plant conservation. They house collections gathered over decades or even hundreds of years, including varieties of plants that may be overlooked elsewhere, fostering heirloom varieties and preserving biological diversity that is the raw material of adaptation. As well as being beautiful and tranquil sites of cultural heritage, these ex-situ resources are treasure troves of biological diversity. Arduaine Gardens shows us that tough choices can be necessary and important to preserve these collections and the surrounding environment.

This project conducted a proof of principle study to assess whether developed computational tools could add value to the field data in annual surveys by Scottish Forestry to parameterise models of the spread of Dendroctonus Micans in space and time. The fitted model was also used to project scenarios of future spread.