22nd Meeting of the EPPO Panel on Diagnostics in Bacteriology

Gent (BE), 2018-11-19/22


The 22nd meeting of the EPPO Panel on Diagnostics in Bacteriology took place in Gent (BE) at the kind invitation of the Institute for Agricultural and Fisheries Research (ILVO). The EPPO Secretariat was pleased to welcome new experts from the Czech Republic and Spain. The Panel continued its task of developing Diagnostic Protocols for regulated bacteria.



Discussions on Diagnostic Protocols

COST Action ‘CA16107 Integrating science on Xanthomonadaceae for integrated plant disease management in Europe’ – EuroXanth

As it is important to maintain links with other regional initiatives that are relevant to EPPO Diagnostic activities, the EPPO Secretariat invited Ms Costa, leader of WP 1 (diagnostics) of the COST Action EuroXanth, to present the activities conducted. Researchers involved in EuroXanth provided suggestions for revision on several EPPO Diagnostic Protocols and have volunteered to be involved in the preparation of the revisions.


New EPPO Diagnostic Protocols after country consultation

The Panel discussed the comments received from EPPO Member Countries on the new pest-specific Diagnostic Protocol on ‘Candidatus Liberibacter solanacearum’. Information resulting from the H2020 EU project ‘Pest organisms threatening Europe (POnTE)’ has been included, in particular the validation data generated during a test performance study performed in the framework of the project. This EPPO Diagnostic Protocol is consistent with the IPPC Diagnostic Protocol for the same pest (ISPM 27 Annex 21). The EPPO Diagnostic Protocol will be finalised in early 2019 and sent for the final approval stage.


Revisions of existing Diagnostic Protocols

Clavibacter michiganensis subsp. sepedonicus

An Expert Working Group met after the Panel meeting and prepared a revised version of the Diagnostic Protocol. The objective of the revision was to include newly developed molecular tests, evaluated in the framework of the Euphresco project ‘Interlaboratory tests for the detection of Clavibacter michiganensis subsp. sepedonicus (potato ring rot) and Ralstonia solanacearum (Potato brown rot)’ and an interlaboratory comparison organized by the Institute for Agricultural and Fisheries Research (ILVO) and the Dutch General Inspection Service (NAK). The diagnostic approach was also aligned with the one in the newly adopted Diagnostic Protocol PM 7/21(2) on Ralstonia solanacearum species complex. The document will be finalized and sent for country consultation in early 2019.


Xylella fastidiosa

A fourth version of the Diagnostic Protocol is in preparation. The Panel discussed how to present the validation data for the combinations of EU priority hosts/matrices in a concise manner. New molecular tests will be described, and the list of current tests will be reviewed to decide on those that should be maintained. Information from the H2020 EU funded projects ‘Pest organisms threatening Europe (POnTE)’ and ‘Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research (XF-ACTORS)’ on laboratory samples (in particular the pooling of samples from asymptomatic plants) will be included. The revision will be finalized by early February 2019 and the document sent for country consultation.


Clavibacter michiganensis subsp. insidiosus

The draft Diagnostic Protocol was reviewed by the Panel. A survey on the molecular tests currently used in the EPPO region was conducted before the meeting and the information gathered was used to select the tests to be included in the revised Diagnostic Protocol. Validation data will be entered in the EPPO Database on Diagnostic Expertise. The revised document will be sent for country consultation in February 2019.


Xanthomonas arboricola pv. pruni

The Panel reviewed the draft Diagnostic Protocol prepared by a group of experts from the Panel. The Appendices describing the molecular tests will be finalised, and the revised document should be sent for country consultation in February 2019.


Future priorities for revision of Diagnostic Protocols

The Panel reviewed the list of EPPO Diagnostic Protocols in Bacteriology to confirm stewards, agree on priorities and plan future work.

The following proposals for revision were made:

  • Xanthomonas citri subsp. citri: to take into account the IPPC Diagnostic Protocol on the same pest ISPM 27 Annex 6 and newly developed molecular tests.
  • Xanthomonas fragariae: to align with the IPPC Diagnostic Protocol on the same pest ISPM 27 Annex 14 and take into account newly developed molecular tests.
  • Erwinia amylovora: to align with the IPPC Diagnostic Protocol on the same pest ISPM 27 Annex 13.
  • Xylophilus ampelinus: a proposal for an Euphresco project to gather information on existing tests, their performances and diagnostic gaps to address will be submitted for consideration and the need for revision will be assessed.
  • Pseudomonas syringae pv. persicae: the Panel considered that a revision should be prepared to update the information on media and to include a reference to a molecular test.
  • Pseudomonas syringae pv. actinidiae: following the suggestion from EuroXanth experts, the Panel discussed the need to remove tests that cross-react with other pathovars and to include newly developed molecular tests. A working group was formed to prepare this revision.
  • Candidatus Liberibacter asiaticus’, ‘Candidatus Liberibacter africanus’, ‘Candidatus Liberibacter americanus’: Mr Cellier (ANSES, FR) presented the preliminary results of the Euphresco project ‘Comparison of real-time PCR detection methods for the plant pathogen 'Candidatus Liberibacter' spp. causing the Huanglongbing disease on Citrus spp. (HLBVALID)’. The results of the test performance study on these pathogens will be available in spring 2019 and a revision will be initiated and validation data included.
  • Pantoea stewartii: an Euphresco project is expected to start in 2019 and the results used for the revision of the EPPO Diagnostic Protocol.


Priorities for new Diagnostic Protocols

Dickeya and Pectobacterium

In order to identify the tests to include in the Diagnostic Protocol, the reports of the Euphresco projects ‘Dickeya species in potato and management strategies (Dickeyaspp.)’, ‘Assessment of Dickeya and Pectobacterium spp. on potatoes and ornamentals (DICKEYA)’, and ‘Assessment of Dickeya and Pectobacterium spp. on vegetables and ornamentals (SOFT ROT)’ will be reviewed. Work will start in Spring 2019.


Update on Euphresco

An update of the projects relevant to bacteriology that were funded through Euphresco since 2015 was presented. The research topics identified for transnational collaboration in 2018 were also discussed.



General discussions

Sample size

The Panel agreed that in a Diagnostic Protocol guidance is mainly given on laboratory samples; sampling procedures in the field or for consignments (in particular, for asymptomatic plants) should be included in inspection procedures (PM3).


The next meeting of the Panel on Diagnostics in Bacteriology will be held in Spring 2020.