This project investigates the biosecurity risks associated with firewood movement in Scotland, a potential pathway for the introduction and spread of plant pests and pathogens to new areas. There are international examples where destructive pests, including the emerald ash borer and Asian longhorn beetle, have been spread through firewood transport, posing a serious threat to native tree species, forestry, and historic tree collections. Despite existing plant health regulations, such as the Statutory Firewood Notification Scheme, there may be limited awareness among firewood distributors about emerging pest threats. Given the potential risks to Scotland’s commercial and native forests, including remaining uninfected elm populations, this research aims to map firewood trade networks, assess biosecurity vulnerabilities, and provide actionable recommendations for risk mitigation.
The study will begin by mapping stakeholders in the firewood sector, including government bodies, transport authorities, and firewood suppliers. An online survey and interviews with major firewood suppliers will help assess domestic firewood movement and identify gaps in awareness and risk assessment. The project will also explore international best practices in firewood biosecurity through literature reviews and expert consultations, as well as analyse data from firewood import records to quantify the scale of international trade. Additionally, the research will evaluate treatment interventions such as heat treatment and steam sterilization to mitigate biosecurity risks. A component of the project is the creation of resources for and recommendations around a potential future public awareness campaign designed to educate stakeholders on the risks associated with firewood movement, drawing on successful international models.
By providing evidence-based recommendations, this research aims to strengthen firewood biosecurity measures, helping safeguard Scotland’s forests from invasive pests.

Image credit: wood by günter from Pixabay

Those carrying out plant conservation work often do not have access to in-depth biosecurity advice and information to help them carry out their activities in a biosecure way. Plants for habitat creation and restoration or for reinforcement of rare plant populations are often produced in an ad-hoc fashion within small community led groups or within commercial nurseries both of which can be a source of pests. In addition, contractors and those carrying out conservation work on the ground are often unaware of the importance of biosecurity when moving machinery and equipment. This is a significant threat to the sensitive habitats in which this work is undertaken because the inadvertent introduction of a new pest would have permanent, far-reaching impacts.

Through literature review, case studies and stakeholder engagement, this project will create a resource which provides specific, clear biosecurity advice to conservation practitioners so that they can produce a biosecurity management plan before a project begins, that would have the potential to become a component of licenced activities in the natural environment.


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Moving to peat-free growing media is essential to allow peat bogs to recover from past exploitation. Peat has been a mainstay of horticulture for many decades and the move away from it will lead to other plant-based products being incorporated into growing media in the future. This may provide the conditions for the proliferation of pests such as sciarid flies, which often occur in decaying plant matter. There are approximately 600 species of sciarid fly in Europe and a total of c.1700 described species globally but the lifecycles of most of these species are currently unknown. In addition, there is conflicting evidence on whether sciarid fly cause physical damage to plants or whether they are just a nuisance. Understanding the extent of damage is very important. By conducting interviews with key stakeholders in the horticulture industry, this project will provide a better understanding of:

1. The specific conditions and contexts where sciarid flies could be a problem in Scotland;
2. Whether sciarid fly infestations are more prevalent in peat-free growing media;
3. The species present and their lifecycles;
4. Management options for sciarid fly.

Upcoming major changes to agricultural policies in Scotland could have significant impacts on crop health (and by extension, crop yields). There is an urgent need, before the agricultural policy reforms are finalised, to review options and identify those that maximise plant health benefits, and those where risks to plant health might be enhanced, in order to consider any mitigations or best practice recommendations that could be put in place.

This project will: (i) Review the evidence (including the scientific and grey literature and existing data) to identify the plant health impacts of the proposed measures within agricultural reform, with reference to Scotland’s key crops and the likely uptake of measures; (ii) Identify potential regulatory options (statutory, basic or enhanced) that could pose an emerging risk for plant health and biosecurity in the context of likely uptake of measures; (iii) Hold a stakeholder workshop to co-design best practices guidance to mitigate plant health risk whilst delivering biodiversity, climate and wider environmental goals and (iv) raise awareness of plant health risks associated with the proposed measures and disseminate best practice guidance to mitigate risk.

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The plant related biosecurity risks posed by bulk aggregates (e.g., sand, stone, decorative wood chips, and soil) to Scotland is currently unclear. It is theoretically possible for plant pests and pathogens to travel within such products but the evidence for this is patchy. The UK Plant Health Risk Register does not mention a specific pathway in relation to bulk aggregates which suggests that these materials are not routinely considered during pest risk analyses (beyond soil/growing media).

This scoping exercise will provide clarity on the biosecurity risks posed by bulk aggregates by a) engaging with the sector to understand where materials originate from, b) quantify how much bulk aggregate material is coming into GB, and c) investigate international approaches to managing the plant health risks regarding bulk aggregates.

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A best practice waste management guidance document was produced during PHC2021/02 (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) to help organisations and businesses manage their plant waste effectively and reduce both the individual business risks, and the wider risks to Scotland’s plant health. However, Project PHC2021/02 identified that there were significant barriers to the uptake of better waste management practices, so an additional programme of knowledge exchange was funded by the Plant Health Centre with the aim of:

1. Sharing the best practice for waste management with those managing waste in plant nurseries, gardens, parks and other plant handling businesses.
2. Ensuring the best practice guidance is available for those applying to become Plant Healthy certified.
3. Producing a peer-reviewed publication on plant waste management to ensure the broadest reach with plant health experts.

There is a clear need to present consistent and focused notifiable pest management information to Professional Operators. There is good information available, however it is in a variety of formats and the quality and type of information is variable. The purpose of this project is to explore if pest information can be set out in a consistent format to support Professional Operators by presenting bespoke plant biosecurity information for their site and associated operations. This information aims to enable Professional Operators to focus their attention on the critical analysis processes required to establish effective plant biosecurity systems.

PHC2022/08 will create summary overview documents that cross references the 39 notifiable pests (from the PHRR) with management measures and the requirements of the Plant Health Management Standard. Therefore, plant pest information will be presented in manner to support businesses and organisations conduct a Site and Operations Pest Risk Analysis.

PHC2022/08 is 50% match-funded from Defra

Previous PHC projects found that biocontrol is one of the elements of Integrated Pest Management (IPM) with a role to play in mitigating pesticide withdrawals. However, it is currently unclear how practical biocontrol is as a suitable alternative to pesticides in Scotland, what the opportunities are for deployment across different sectors and what barriers exist to uptake (include regulatory).

Research on biocontrol agents is required to understand a) what relevant previous work has taken place, b) the potential benefits for agricultural, horticultural and forestry applications in Scotland, and c) is the current risk assessment framework and regulatory system fit for purpose?

This project will improve our understanding of the potential of biocontrol agents in Scottish production systems and gardens; synthesising findings from workshops with stakeholders and literature review.

The Plant Health Centre was commissioned by the Scottish Government to review evidence relating to the potential of new gene editing technologies to address plant health issues in Scotland, with potential benefits, barriers to deployment and dis-benefits noted

Originally raised as a plant health issue of potential concern, the health of Alder trees in Scotland was initially investigated in project PHC2019/09: Health status of Alder in Scotland. This preliminary study found that there could be a legitimate concern over Alder that may have complex causes (several biotic and abiotic stresses were noted), and the timeline of these health issues (gradual or rapid) was unclear. Further scoping and examination of the problem by established experts was recommended, leading to this project. The project will conduct:
• Expert visitation of sites to seek evidence of problems with alder health, gain some understanding as to possible causes, and identify key dimensions of a thorough study should this prove warranted. Lab work to confirm field diagnoses.
• Preliminary citizen science request inviting site-specific records of concern over alder health (potentially via the trained Observatree volunteer network to gather data), with analysis to identify any geographic clustering.
• Produce recommendations for further work including; refined survey methodologies for widespread application by interested organisations; identification of potential candidate sites for detailed study over time, and; a discussion document on risks to existing alder of expansion of riparian woodland.