The sector represents a major component of Scotland’s rural economy – providing significant employment and raw materials for wood processing industries. Sustainable forest management seeks to deliver these economic benefits alongside important ecosystem services such as carbon sequestration and flood mitigation, provision of wildlife habitat and opportunities for recreation and a range of leisure activities. Pests and diseases threaten the continued long-term delivery of these benefits.
The forest area of Scotland expanded during the twentieth century through the efforts of the Forestry Commission and private owners to develop a domestic wood supply and provide rural employment. A number of introduced species, such as Sitka spruce, were key to afforestation of marginal agricultural sites and now are central to the wood processing industry. Woodland now occupies approximately 17% of the land area of Scotland and provides 44% of the GB softwood harvest, producing about 1.5 million m3 of sawn softwood. Plant health threats to the forestry sector include a number of recently introduced pests and diseases (e.g. Phytophthora ramorum, pine tree lappet moth, ash die-back), on-going management of endemic ones (e.g. large pine weevil and Heterobasidium annosum) and risks of those yet to arrive (emerald ash borer, Ips typographus and many other organisms potentially introduced through trade in plants, wood and packaging).
Impact: Improved understanding of costs and benefits of pesticide use across Scottish sectors and an impact analysis for the most likely withdrawal scenarios such that key gaps can be identified and their impact quantified in order to inform pesticide policy.
Impact: Easily accessible tool for PHC and government plant health officials to assess possible impacts of climate on pests and pathogens in Scotland.
Compared to threats such as climate change and habitat fragmentation, plant health issues are poorly represented in international and national biodiversity strategies such as the Aichi Targets of the Convention on Biological Diversity, the Global Strategy for Plant Conservation, and the Scottish Biodiversity Strategy. Work is thus required to provide strategic guidance on the inclusion of plant health threats into the next iteration of the biodiversity strategies.
Impact: Direct guidance and input for plant health issues into the new Scottish Biodiversity Strategy; best-practice example of plant health integration into national biodiversity planning (model for other countries).
The aim of this commission is to establish the template and initial population of a curated online resource bank for plant health threats to the natural environment in Scotland. This will include assembly of, or signposting to, available existing resources. Where applicable, it will also include authoritative distillations of the key issues targeted at non-specialists. Where there are conflicting sources of advice/recommendations, the scope is not to achieve reconciliation of these issues, but rather to simply note that different perspectives exist. The content will be housed on the Plant Health Centre website (https://www.planthealthcentre.scot/).
Impact: Increasing the accessibility of information for land managers with responsibility for the natural environment, but a lack of specialist expertise in plant health
Impact: Improved understanding of concepts and options amongst the Scottish stakeholder community; a basis for gap analysis by the PHC.
Impact: Improved risk assessment; better equipped stakeholders and government plant health officials; improved coordination of plant health activities in Scotland.
Although Xylella has so far not been detected in Scotland, an outbreak would have serious impacts on any host plant-related activities/businesses and the wider environment. An essential aspect of ensuring Scotland’s preparedness for the possible arrival of Xylella is to prepare a risk map for the likelihood of the arrival of Xylella together with the consequences for key elements of the Scottish economy (directly and indirectly impacted) in the event of an outbreak. Data relevant to the risk mapping for Scotland would include location of sites involved in plant imports, volume of plants imported, impact on business trading in plants if an outbreak is detected and the wider environmental impact.
Impact: This project will contribute to Scottish Government’s contingency and preparedness measures for the possible arrival of Xylella fastidiosa by mapping the risk of likelihood and impact of an outbreak.
There are several species of insects that could vector Xylella fastidiosa in the UK including the meadow spittlebug (Philaenus spumarius), which is very common in Scotland. An outbreak of Xylella in Scotland would have serious impacts on the affected grower/nursery and any other host plant-related activities/business within a 5km buffer zone. Therefore, in order to establish the potential for these bacteria to spread, should they be introduced, it is important to identify and get an understanding of the abundance of potential Xylella vectors in Scotland. The WrEN project (http://www.wrenproject.com/), presents a unique opportunity to make use of existing insect collections to map the occurrence of potential Xylella vectors within agricultural woodlands across Scotland. Since 2013, partners on the WrEN project have surveyed over 130 secondary and ancient woodland sites for habitat and wildlife in two regions of mainland Britain. To date, over 1100 species have been recorded from a wide range of taxa. Vegetation structure has been characterised at all sites including information on tree species richness, tree density and size, understorey and canopy cover. In addition, the surrounding landscape has been mapped at a range of spatial scales up to 3 km from each site.
Impact: This project will contribute to Scottish Government’s preparedness measures for the possible
arrival of Xylella fastidiosa by identifying and mapping the distribution of potential vectors of Xylella
Biosecurity practices to support plant health: a review of knowledge and practice
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.
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.
Improving knowledge of Xylella fastidiosa vector ecology: modelling vector occurrence and abundance in the wider landscape in Scotland
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.
A review of gene editing for the benefit of plant health
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.
Assessment of large-scale biosecurity risks to Scotland
PHC commissioned an assessment of large-scale biosecurity risks with a focus on three areas of concern:
- non-specialist and online horticulture sales;
- landscaping and infrastructure;
- 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.
Assessment of large-scale plant biosecurity risks to Scotland from non-specialist and online horticultural sales
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.
Assessment of plant biosecurity risks to Scotland from large scale plantings for landscaping and infra-structure projects
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.
Assessment of plant biosecurity risks to Scotland from large scale tree plantings for environmental benefits
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.
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.
Assessment of suitability for EAB invasion for Scotland and the UK
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.
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.
PHC2020/09: Economic Impact of Pesticide Withdrawals to Scotland, with Case Studies
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.
PHC2018/15: Potential Impacts Arising from Pesticide Withdrawals to Scotland’s Plant Health
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.
Impact of climate change on the spread of pests and diseases in Scotland
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.
Modelling Framework for invasive pests: Emerald ash borer as a case study
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.
Expansion of PHC Online Plant Health Resources
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.
18-Month Review Summary Leaflet
The Plant Health Centre completed an in-depth review of its first 18-months of activity for our funder (the Scottish Government through RESAS) in September 2019. While the full report is not yet available to the public, we have created a summary leaflet that outlines out achievements over this period.
Threat: Oak Processionary Moth
Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from Oak Processionary Moth to Scotland.
Threat: Bud worm
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
Threat: Emerald ash borer and Bronze birch borer
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
Threat: Larger Eight toothed spruce bark beetle (Ips typographus)
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
Threat: Longhorn beetles
Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from longhorn beetles to Scotland
Threat: Phytophthora ramorum
Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from Phytophthora ramorum to Scotland
Threat: Xylella fastidiosa
Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from Xylella fastidiosa to Scotland
Development of an online, user friendly plant health resource bank for the Scottish Natural Environment
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 use of mobile technology to enhance plant health monitoring and awareness in Scotland
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?
Difficult choices to protect gardens and the environment
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.
Spatio-temporal modelling of great spruce bark beetle (Dendroctonus Micans) in Scotland
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.