6th EPPO Workshop for Heads of Plant Pest Diagnostic Laboratories
06/07-03-2025, Saku, Estonia
The EPPO Workshop for Heads of Plant Pest Diagnostic Laboratories was hosted by METK - Centre of Estonian Rural Research and Knowledge / Maaelu Teadmuskeskus and attended by 40 participants, from 24 EPPO countries. Several experts also joined remotely to deliver presentations on related topics. The workshop was chaired by Ms Tikka (EPPO Director-General) and Ms Lasner (Head of METK Laboratory Plant Health and Microbiology Unit) with the support of EPPO Scientific Officers Mr Aoutil and Ms Trontin, EPPO Administrative Officer Ms Nikolaeva and local organizers.
The objectives of the workshop were to:
- Share experiences on tracing the origin of pest outbreaks (including new techniques to trace strains/populations)
- Provide information which is useful for pest tracking and outbreak management
- Share experiences on the biological relevance of obtained diagnostics results and their interpretation.
The EPPO Secretariat sincerely thanks all attendees for their active participation, for sharing their professional experience and knowledge, and for providing valuable input. The EPPO Secretariat extends special appreciation to METK for hosting the meeting, and for ensuring excellent organization, to the workshop organizing committee who supported the EPPO Secretariat in the preparation of the workshop agenda and to facilitators of the group discussions.
The meeting opened with a welcome speech by METK Director-General Mr Andre Veskioja who provided an insight into the METK structure, activities and goals.
Session 1 - Trace and Track (chaired by Olga TIKKA, EPPO Director-General)
The first part of the session included 10 presentations (see below) devoted to the 2 general topics:
- Tracing the origin of regulated pest outbreaks, and newly developed techniques that can be used to trace and track strains/populations;
- Importance of the communication between laboratories and NPPOs when tracing/tracking pests.
In the second part of this session participants worked in small groups to brainstorm on 3 different topics:
- Essential data required for tracing and tracking pest outbreaks;
- Challenges in tracing and tracking outbreaks;
- Trace and track results: what next?
Outcomes:
Essential data required for tracing and tracking pest outbreaks
Through a board game deciphering a hypothetical outbreak in the islands of Terra Florivora, Mr van de Vossenberg presented the data and factors that need to be considered when tracing the origin of an outbreak. The discussion emphasized the complexity of the trace and track process and the fact that the outcomes are not always known in advance. A key point raised was the importance of communication with NPPOs. The group considered that even if an initial case remains unsolved, the data gathered when attempting to trace the origin of the pest can still advance scientific knowledge on the pest’s behaviour, ecology, or on potential mitigation strategies.
Challenges in tracing and tracking outbreaks
The groups identified major challenges when tracing and tracking pest outbreaks. The availability and adequacy of diagnostic tools in laboratories were discussed, with an emphasis on the need to use more advanced tools (e.g. High Throughout Sequencing (HTS)). Other challenges include determining the best sampling procedure and managing an efficient surveillance/tracking programme with limited resources (financial constraints, trained workforce). The difficulty in predicting how a previously studied pest might behave in a new environment was also raised.
Trace and track results: what next?
The groups discussed the importance of efficient communication with the NPPO. Ideally a procedure should be defined in advance between the laboratories and the NPPO to ensure a common understanding of the needs of the different parties. The participants highlighted that it can be difficult to explain some diagnostic concepts or considerations to NPPOs (e.g. the concept of an inconclusive result, the importance of effective sampling, the uncertainties associated with some techniques (e.g. HTS and real-time PCR)). It is important to take the time to explain the different concepts to risk managers. In addition, it was noted that it is not always possible to have face to face meetings with the NPPO which may sometimes be a challenge. The participants highlighted that adapting the diagnostic work following an outbreak may be challenging in terms of resources (as more samples are received in the laboratory) and also in relation to accreditation. Finally, the participants highlighted that unofficial reports of new pests are challenging and may have important consequences for trade. They suggested that is it necessary to raise awareness among researchers and within universities to better overcome these issues.
Session 2 - Biological relevance of diagnostics results (chaired by Helena LASNER-IVAROLA, Centre of Estonian Rural Research and Knowledge, EE)
The first part of the session included 6 presentations (see below) devoted to the 2 general topics:
- Actions to be taken following HTS test results
- Experience and challenges concerning the interpretation of the biological relevance of test results
In the second part of this session participants worked in 3 groups to brainstorm on 3 different topics:
- The different interpretations of biological relevance
- What steps allow assessment of if the pest is present?
- Challenges in the assessment of viability and pathogenicity
Outcomes:
The different interpretations of biological relevance
The participants shared what ‘biological relevance’ means to them and ranked different factors used to determine the biological relevance of a known or unknown pest. Overall, biological relevance was associated with the impact and the risk associated with a pest. Impact was considered as the most important factor to consider when evaluating biological relevance. However, throughout the discussion it was noted that all factors raised (symptoms, distribution, transmission, biological activity, etc.) are important.
Visual output of the interactive tool used during the group discussion
Which steps allow assessment of whether the pest is present?
The groups highlighted that laboratories are only able to assess the samples they receive. Assessing the status of a consignment or place of production is the responsibility of risk managers and depends on the results provided by laboratories but also on the sampling performed by inspectors. The groups highlighted that the contextual information on a sample (e.g. symptoms, origin, host) and the performance of the tests in a workflow are important in determining whether a pest is present or not. The groups also highlighted that the tests performed to assess the presence of a pest in a sample may vary depending on the context of the analysis (surveillance or official control) and on the demand of the customer. In critical cases, more tests are usually performed to ensure the validity of the results obtained. It was noted that viability is not routinely evaluated. The uncertainty associated with a test result is usually discussed with the NPPO to provide information for their risk analysis and take appropriate measures. It was noted that some (but not all) laboratories are involved in drafting pest risk analysis and providing guidance to NPPOs. Depending on the countries, some laboratories can search for other organisms (than the target pest) in the sample whereas other laboratories should only focus on testing for the target (quarantine) pest(s) requested by the NPPO.
Challenges in the assessment of viability and pathogenicity
Firstly, the groups discussed the meaning of ‘viability’ and ‘pathogenicity’. The definition of viability was clear and used across different disciplines, except in virology. However, terminology related to pathogenicity varied between disciplines highlighting the need for more harmonization. The groups highlighted the challenges in assessing viability and pathogenicity, such as the fact that it is time-consuming, there are limitations in plant material availability, and a lack of standardization. It was noted that viability and pathogenicity tests are not routinely performed and are usually carried out following a request from the client (NPPO, private company) although they may be done based on a decision from laboratory managers. The groups discussed the challenges associated with the assessment of viability of pests in treated materials, and with the inconsistency of test results (e.g. molecular tests vs viability tests). The groups suggested the organisation of training courses or workshops on pathogenicity tests (e.g. for Tobamoviruses, Synchytrium endobioticum, Xylella fastidiosa and Globodera species).
General Conclusions and Recommendations from the Workshop
- Ensuring efficient communication between laboratories and NPPOs is essential and should focus on laboratories’ activities and capacity, and on the advantages/disadvantages of diagnostic tests and associated uncertainty.
- Procedures should be formalized to ensure efficient communication.
On tracing and tracking pests:
- Tracing and tracking pests is not a core mission of diagnostic laboratories and requires additional resources and expertise. However, it was noted that several laboratories are involved in activities related to tracing/tracking pests and collaboration between laboratories should be encouraged to increase capacity and share experiences.
- There is a need to increase awareness on the obligation to report quarantine pests to NPPOs, in particular amongst researchers. The topic could be raised in the EPPO Panel on Plant Protection Information.
On biological relevance:
- The interpretation of HTS results is challenging. Having more harmonized bioinformatic pipelines could help facilitate the interpretation of test results and comparison of results obtained in different laboratories.
- Biological characterisation of new viruses, which have been detected and identified through HTS, using e.g. bioassays and field surveys is important to evaluate their potential impact.
- Each diagnostic method has advantages and disadvantages within the diagnostic workflow. Harmonization may be difficult even when the same tests are used, and validation data are key for the interpretation of test results.
- Bioassays/pathogenicity tests should be interpreted with caution as different environmental conditions may trigger different responses.
- Training on pathogenicity tests could be organised and a glossary to further harmonize terminology could be prepared.
PRESENTATIONS (Session 1)
Beat RUFFNER, Swiss Federal Research Institute (Switzerland)
Marta KOSTETSKA, Lviv State Phytosanitary Laboratory (Ukraine) & Iryna MATSIAKH, Ukrainian National Forestry University (Ukraine) + Swedish University of Agricultural Sciences, SLU
Ana Belen RUIZ GARCIA, Instituto Valenciano de Investigaciones Agrarias (IVIA) (Spain)
High Throughput Sequencing (HTS) provides new insights into the olive leaf yellowing complex
Bart VAN DE VOSSENBERG, The Netherlands Institute for Vectors, Invasive plants and Plant health (NIVIP) (Netherlands)
Nicolas MARIETTE, Plant Health laboratory – Nematology unit, ANSES (France)
Two decades of epidemiological surveillance of the pine wood nematode in France
Maaike BRUINSMA, NVWA (Netherlands)
The role of new diagnostic tests in outbreak management
Luca FERRETTI, CREA (Italy)
Francesco PALMISANO (NPPO of Italy) & Maria SAPONARI, CNR (Italy)
Rebecca WEEKS, FERA & Aaron HOYLE, DEFRA (United Kingdom)
Track and trace toolbox; investigating the origins of plant pest interceptions
Eugénia DE ANDRADE, The National Institute of Agricultural and Veterinary Research (INIAV) (Portugal)
Communication with the NPPO: best practices and lessons learned
PRESENTATIONS (Session 2)
Mathieu ROLLAND, ANSES (France)
Interpretation of HTS results in plant virus diagnostics: lessons learned and comparative practices
Kris DE JONGHE, ILVO (Belgium)
Adrian FOX, FERA (United Kingdom)
Stephan KÖNIG, German Federal Research Centre for Cultivated Plants (JKI) (Germany)
Methods for viability testing in Nematology –proof for treatment efficacy in residual soils
Luís BONIFACIO, The National Institute of Agricultural and Veterinary Research (INIAV) (Portugal)
Biological relevance of quarantine pests’ detection
Robert VREEBURG & Maria BERGSMA-VLAMI, NIVIP (Netherlands)