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: Kirsty Park
Xylella fastidiosa is a bacterial plant pathogen that can cause disease in a broad range of hosts, including Polygala myrtifolia, Olea europaea, Rosmarinus Officinalis, Lavandula sp., Prunus sp. and Nerium oleander. 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. The bacteria are transmitted by xylem feeding insects from the Cercopidae family, which include froghoppers and spittlebugs.

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
in Scotland.
Project Lead: Fiona Highet
The unexpected finding of the presence of Lso and a potential vector species in Scotland raised significant concerns (Sjolund et al. 2017). However, without further information this cannot be put into context. The likelihood is that the disease and possible vector have been present in Scotland for a long time, and yet our crops remain symptomless. Therefore, without the introduction of another vector risk may remain low. In order to confirm this and establish the current risk of transmission to crops, the following information is urgently required: the distribution of potential pyllid vectors including T. anthrisci in regions of Scotland, the presence of Haplotype C Lso within these vectors, a genomic comparison of the Scottish Haplotype C Lso with disease-causing Haplotype C Lso from Finland and Spain, and establishment of T. anthrisci’s vector potential through the development of a breeding colony.

The knowledge required to identify different psyllid species is highly specialised but is essential in order to gain a wider understanding of the disease threat that such insects cause. As few in Scotland have this specialisation (including SASA), it is deemed important to up-skill others by running a training course on psyllid identification for entomologists within Scottish organisations to better enable Scotland to deal with possible Lso threats both now and in the future.

Impact:
This project will contribute to Scottish Government’s ability to control pests / diseases by increased knowledge on the presence and distribution of Liberibacter solonacearum and its host psyllids in Scotland and the potential of these organisms to cause and spread disease.
Project Lead: Fiona Burnett
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.

Publications

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

A targeted analysis of the impact of insecticide withdrawals in Scotland, in the context of alternative control options

July 2023

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.

PHC Annual Report 2022-2023

July 2023

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. 

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

Biosecurity practices to support plant health: a review of knowledge and practice

March 2023

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.

Agriculture | Final Report and Policy Document

Modelling the spread of PCN in Scotland

Authors: Peter Skelsey
March 2023

Potato cyst nematodes (PCN) cost Scottish agriculture over £25 million/year and threatens food security in the developed and developing world. Improved understanding of PCN epidemiology is a priority for the Scottish potato industry, with spatial and temporal modelling identified by the recent PHC PCN working group as essential components.

Enhancing the Plant Health Centre’s communication with stakeholders

February 2023

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.

Horticulture, Agriculture | Final Report and Policy Document

Perceptions of pest risk and differences in IPM uptake by arable farmers and agronomists in Scotland

November 2022

Pesticide use remains an important tool in managing pest, weed and disease risks to crops and maintaining profitable production. There are several drivers for reducing reliance on pesticides and promoting the uptake of more sustainable practices through integrated pest management (IPM).  By identifying IPM information networks it may be possible to improve the flow of information to farmers by targeting their preferred information sources.  Better informed farmers and agronomists can make better IPM decisions.  Therefore, this project undertook a telephone survey to collect information on currently perceived invertebrate pest and disease threats in Scotland, the level of IPM uptake, and the information sources they relied upon.  

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

Improving knowledge of Xylella fastidiosa vector ecology: modelling vector occurrence and abundance in the wider landscape in Scotland

May 2022

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.

Assessment of large-scale biosecurity risks to Scotland

December 2021

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.  

Assessment of large-scale plant biosecurity risks to Scotland from non-specialist and online horticultural sales

October 2021

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

October 2021

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

October 2021

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

October 2021

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.

Agriculture | Policy Document

A new IPM Planning Tool for Scottish growers

March 2021

Integrated pest management (IPM) is a holistic approach to managing harmful organisms which maximizes profitability and minimises negative impacts on the environment. IPM aims to reduce reliance on pesticides and promoting IPM is identified as a key action in support of a National Action Plan. To promote IPM practices and improve on-farm uptake, it is essential to understand current uptake levels and better understand what motivates farmers to further adopt IPM. A new integrated pest management planning tool for Scottish growers has been launched, replacing a previous IPM plan. The new plan uses stakeholder derived metrics to value how important different interventions, such as rotations or varieties, are in achieving sustainable reductions in invertebrate pest, weed and disease risk.

Horticulture, Agriculture | Final Report and Policy Document

Monitoring for BMSB in Scotland - Final Report and Policy Summary

March 2021

The increase in global trade brings with it the risk of spread of new pests and diseases into Scotland. Halyomorpha halys, Brown Marmorated Stinkbug (BMSB) is an invasive pest that has already become established in North America and several European countries. The insect aggregates inside houses over winter and can cause problems as an urban nuisance pest in homes as well as being a pest of agriculture. In this project, co-ordinated monitoring for the presence of BMSB was undertaken by teams at SASA and the James Hutton Institute. A reference collection of voucher specimens of common UK stinkbug species was established, including DNA barcoding. A process-oriented climate-based niche model was used by a team at SRUC to determine the areas in Scotland that are suitable for the establishment of BMSB under current and future climates.

Recommendations and suggested 'next steps', including encouraging further surveillance, are detailed in the report and policy summary documents.

Agriculture | Policy Document

PCN Working Group - Final Report

March 2021

Following a Ministerial round table meeting on PCN in June 2020, a working group of over 50 potato industry, government and academic partners was set up (from both Scotland and the wider UK) to identify a clear strategy for dealing with the PCN crisis. Following over 320 person hours of scheduled meetings, plus many days of personal discussions, recommendations for how to combat the growing threat of PCN to the Scottish potato industry have been proposed.

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

PHC2020/09: Economic Impact of Pesticide Withdrawals to Scotland, with Case Studies

March 2021

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

November 2020

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

June 2020

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. 

Expansion of PHC Online Plant Health Resources

May 2020

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.

 

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.