Agriculture

With plentiful rain and long summer day lengths, Scotland producing some of the highest yielding and best quality crops in the world. But conditions that promote good crop growth are often good for pests and pathogens too and in Scotland 15-20% of our crops are lost to pests and diseases annually. 

These losses to pests and diseases   amount  to almost a million lost tonnes per year with a value close to £200 million. Dealing with the endemic disease burden  inevitably means higher prices in supermarkets, hard times for growers  and a knock to the economy but, in addition to this current burden  many more pests and pathogens are arriving or threatening our borders.  Priority concerns for the sector are sustainable methods of reducing and managing pest and disease risks that lessen reliance on pesticides. Current acute issues which have been highlighted by stakeholders  are pesticide resistance developments in some of our endemic pests and diseases, and also concerns over product withdrawals through the regulatory processes. Concerns over resistance development in endemic diseases are a major plant health concern in many crops in the agriculture sector. Potato blight and ramularia in barley being two current example where new issues emerged in 2017.

 

Projects

Project Lead: Mariella Marzano
The UK and Scotland have ambitious tree planting targets, with a major driver being carbon sequestration. Scotland’s Forest Strategy outlines a target of 15,000 ha per year. In addition to carbon management, other major drivers for tree planting are commercial forestry, habitat restoration and the establishment of new woodlands for biodiversity and amenity value. Scotland’s Forest Strategy outlines a target of 3,000-5,000 ha of new native woodland per year, and restoration of an additional 10,000 ha of native woodland. This involves planting a large volume of trees. There is considerable uncertainty as to where and how this volume of trees will be sourced, and associated uncertainty as to the biosecurity threats posed. The aim of this project is to improve our understanding of current biosecurity awareness and practices within the arenas of woodland creation/ expansion and habitat restoration in Scotland.

Impact: Determine the main barriers to ensuring that future planting for environmental restoration and conservation will minimise plant health risks.
Project Lead: Mariella Marzano
Large scale infra-structure projects such as transport networks and major housing projects typically include extensive landscaping and planting programmes. These operate at a large scale, often require instant visual impacts (semi-mature shrubs and trees) and face significant cost pressures. The modest scale of domestic production creates challenges in obtaining material from local sources, which can favour low-cost large-scale plant imports with associated risks of pest and disease entry. This project will fill in key knowledge gaps with those responsible for selecting, procuring and planting plants and trees on a large-scale to provide an understanding of how/whether biosecurity features in their decision-making and make recommendations for any changes required to improve bio-secure practices.

Impact: Provide Scottish Government policy with an assessment of the major biosecurity pitfalls and opportunities arising from large-scale landscaping plantings.
Project Lead: Mariella Marzano
Retail horticulture is a large-scale industry in the UK, with ornamental horticulture and landscaping worth an estimated £24.2 billion national GDP in 2017. The industry is characterised by a large volume of individual transactions and the transport of a diverse range of plant materials (with accompanying soil and packaging) to a highly distributed set of final destinations (households). These horticultural sales represent a complex and pervasive vector network, which carries the risk of transportation of pests and pathogens to surrounding parks and gardens, agricultural systems, woodlands, forests and the wider environment. The diversity of the plant material in trade and the multitude of suppliers and recipients creates a major challenge for managing biosecurity. This project will identify decision-makers, their knowledge, attitudes, and behaviours relating to plant health, and assess opportunities and barriers to better plant biosecurity and the potential role of a Plant Health Assurance Scheme.

Impact: This project will enable policy to identify and prioritise plant biosecurity vulnerabilities from non-specialist and online horticultural sales.
Project Lead: Katy Hayden
A previous PHC project (PHC2018/11) created an online Resource Bank for plant health threats to the Natural Environment sector in Scotland, which includes an assembly of, or signposting to, available existing resources. The PHC recognised that for the remaining three sectors (Forestry, Agriculture and Horticulture) information on plant health is more available but the quality and relevance to Scotland is often not clear. This project has expanded the PHC’s online resource to signpost users and practitioners to relevant and reliable information and to address a broad spectrum of plant health topics, from diagnostics and control to outreach and education.

Impact: 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.
Project Lead: Alison Dolan
The brown marmorated stink bug (BMSB) Halyomorpha halys is an invasive species of the shield bug family. It has been intercepted in the UK on several occasions, likely posing a ‘when’ not ‘if’ risk to crops. The BMSB attacks a wide range of hosts including raspberry and sweet cherry, two main soft and stone fruit crops grown in Scotland. The conditions in Scotland appear to be suitable for the establishment of this pest and the Scottish soft fruit industry are concerned about the threat. The soft fruit industry trades with countries with strict biosecurity measures for this pest, and assurances are being sought to verify that every measure is being taken to assess whether the pest is present in Scotland. A failure to do this could have economic consequences for both local markets and on Scottish export markets. This project will survey for BMSB presence and model the potential spread of BMSB in Scotland, including the likely effects of climate change.

Impact: Investigate the suitability of the Scottish climate for establishment and spread of the pest should it be introduced to provide data for a Scottish-specific BMSB risk assessment.
Project Lead: Vivian Blok
Potato cyst nematode (PCN) remains an important threat to potato production in the UK as elsewhere and is a particular concern to the Scottish seed industry, since land found to be infested with the pest cannot be used to grow seed. However, ware crops can still be grown which may exacerbate issues for the seed potato industry. While there is good cultivar resistance (ca 50% of potatoes in Scotland) to species Globodera rostochiensis, helping to halt its spread, there is little resistance to a second species (G. pallida), which has a greater potential to increase and spread. This is likely to have a detrimental effect on the seed industry in Scotland in the future but how much of an effect is not clear. This project is divided into four parts to help better understand the threat from PCN in the future:
• A review of possible interventions to include a review of PCN management in other countries to inform the work packages below:-
• Modelling future risks of both G. rostochiensis and G. palida using interventions identified in the review and climate scenarios.
• Grower behaviours and attitudes to interventions, to include input from industry stakeholders.
• An economic analysis of likely impact in Scotland based on a range of possible interventions.

Impact: A clearer understanding of possible control options, economic impacts of available interventions and the likelihood of growers and buyers adopting new resistant varieties, altering rotation practices or any other interventions such that recommendations on best strategies (including statutory controls) can be made.
Project Lead: Daniel Chapman
Xylella fastidiosa is a bacterial plant pathogen that can cause disease in a broad range of hosts. Disease symptoms include leaf scorch, wilting of foliage, dieback and plant death. Xylella fastidiosa was first detected in Europe in 2013 in Puglia in Italy and was identified as subspecies pauca which has gone on to devastate olive plantations in this region. There are currently major Xylella outbreaks in Southern France, including Corsica, Italy, mainland Spain and the Balearic Islands. Although Xylella has so far not been detected in Scotland, an outbreak would have serious impacts on any businesses where Xylella is detected and the wider environment. An essential aspect of ensuring that Xylella is not introduced to Scotland is to establish, through modelling, that national surveillance monitoring aimed at detecting a Xylella outbreak is effective. In addition, it is important to identify which epidemiological parameters most strongly influence the effectiveness of surveillance, to guide where future empirical research should be targeted to reduce any uncertainty.

Impact: This project will contribute to Scottish Government’s preparedness measures for the possible arrival of Xylella fastidiosa by ensuring surveillance monitoring is effective and by identifying the key knowledge gaps for effective surveillance.
Project Lead: Andy Evans
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. There is an urgent need to quantify the impact on Scottish plant health that will arise from pesticide withdrawal scenarios and to set this in the context and time frame of alternative management tools. This will be used to inform recommendations on pesticide strategy at the Scottish, UK and EU levels going forward. A synthesis report of available information is required to identify products at risk and work through scenarios for the plant types, pests and diseases of importance in Scotland. This will be a project where cross-sectoral dialogue between the plant health sectors of agriculture / crop production, horticulture, forestry and the environment will be necessary. The project will review existing information and a key output will be summary recommendations appropriate for use by policy makes. The bid must include time to engage with in cross-sectoral dialogue and with Scottish Government staff to discuss and progress early drafts.

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.
Project Lead: Adam Kleczkowski
The movement of plant pests and pathogens into Scotland in likely to increase in the coming years, e.g. due to changes in trade, potentially increasing from outside Europe following Brexit, while their spread and severity could be affected by climate change (both positively and negatively). It is therefore vital that we understand the role of climate on the impacts of such pests and diseases across the whole of Scotland, in relation to the distribution of plant hosts, allowing us to target potential control options on the main threats. To allow plant health professionals and others to assess such impacts in as straight forward a way as possible, web- / desktop-based tools are needed that offer quick and easy access to complex computer models. These models should be as comprehensive as possible, allowing new information on pests, pathogens and their hosts to be added as it becomes available.

Impact: Easily accessible tool for stakeholders and government plant health officials to assess possible impacts of climate on pests and pathogens in Scotland.
Early scoping of plant health priorities with key Scottish stakeholders and discussions at the PHC launch event indicate a complex landscape of plant health information sources, confusion amongst stakeholders and a perception of information overload. To inform future KE methods and priorities, a network analysis is required to identify the sources of information and the strength of their effect on Scottish stakeholder communities.

Impact: Improved understanding of concepts and options amongst the Scottish stakeholder community; a basis for gap analysis by the PHC.

Publications

Forestry, Horticulture, Agriculture, Environment | Final Report and Policy Document

The use of mobile technology to enhance plant health monitoring and awareness in Scotland

August 2019

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?
Agriculture | Final Report and Policy Document

Assessing the potential of the psyllid Trioza anthrisci to vector Liberibacter solanacearum (Lso) in Scotland

June 2019

The aim of the project was to assess the distribution and population numbers of the psyllid Trioza anthrisci and it’s potential as a vector of ‘Candidatus Liberibacter solanacearum’ (Lso).  The project has allowed the PHC to better understand the distribution and number of T. anthrisci populations in carrot growing areas to better inform assessment of the risk of disease transmission to crops in Scotland. 

Horticulture, Agriculture | Policy Document

Impact on Scottish crops if the molluscicide metaldehyde is withdrawn

December 2018

This report sets out estimates for the crop loss and value to Scottish crop production should the molluscicide metaldehyde be withdrawn. This would leave ferric phosphate as the only available chemical control option. Short term losses are negligible as the substitution of ferric phosphate carries no additional treatment costs and has equivalent efficacy. Longer term there is some risk should resistance arise to this single site mode of action active, and ferric phosphate (although of lower mammalian toxicity to metaldehyde) has some environmental impacts of its own.