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Justification for qualification based on EPPO PM 4 Standards
Justification for disqualification
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NAME OF THE ORGANISM: Pseudomonas viridiflava (PSDMVF)

GENERAL INFORMATION ON THE PEST

Name as submitted in the project specification (if different):

Pest category:

Bacteria

1- Identity of the pest/Level of taxonomic listing:

Is the organism clearly a single taxonomic entity and can it be adequately distinguished from other entities of the same rank?

Yes

Is the pest defined at the species level or lower?:

Yes

Can listing of the pest at a taxonomic level higher than species be supported by scientific reasons or can species be identified within the taxonomic rank which are the (main) pests of concern?

Not relevant: Fruits (including hops) sector

If necessary, please list the species:

Is it justified that the pest is listed at a taxonomic rank below species level?

Not relevant

Conclusion:

Null: Fruits (including hops) sector

Justification (if necessary):

2 – Status in the EU:

Is this pest already a quarantine pest for the whole EU?

Presence in the EU:

Yes

List of countries (EPPO Global Database):

Conclusion:

Candidate

Justification (if necessary):

Pseudomonas viridiflava has been reported in various countries in the EU: France (Parisi et al., 2019), Greece (Goumas & Chatzaki, 1998), Italy (Scortichini & Morone, 1997), Poland (Sulikowska & Sobiczewski, 2008)

HOST PLANT N°1: Prunus armeniaca (PRNAR) for the Fruits (including hops) sector.

Origin of the listing:

Commission Implementing Directive (EU) 2014/98/EU and Commission Implementing Regulation (EU) 2019/2072

Plants for planting:

Plants intended for planting

3 - Is the pest already listed in a PM4 standard on the concerned host plant?

Yes

Conclusion:

Evaluation continues

Justification (if necessary):

Inspection for 'Pseudomonas viridiflava' on apricot is recommended in EPPO Standard PM 4-30 Certification scheme for almond, apricot, peach and plum. In the responses to the questionnaire, DE supported deregulation considering that no feasible and effective measures are available. The Fruit SEWG also recommended reassessing whether plants for planting was a significant pathway compared to natural spread. Evaluation continues on these criteria.
Remark: The assessment performed covers the given host species as well as interspecific hybrids with other Prunus species.

4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):

Conclusion:

Not candidate

Justification:

Pseudomonas viridiflava is a polyphagous pathogen causing damages to e.g. tomato (Solanum lycopersicum), melon (Cucumis melo), chrysanthemum (Chrysanthemum morifolium), eggplant (Solanum melongena) (Goumas & Chatzaki, 1998; Sarris et al., 2012). It can cause blossom blight in kiwi (Balestra et al., 2008). It has also been reported in various Prunus spp., like apricot (P. armeniaca; Parisi et al., 2019), plum, sour cherry and peach (Sulikowska & Sobiczewski, 2008; Scortichini & Morone, 1997), where it caused canker, shoot necrosis and tree apoplexy during growing season (Parisi et al., 2019; Scortichini & Morone, 1997).
P. viridiflava is thought to be carried in aerosols in wind-driven rain within and between crops. It can be carried as a surface contaminant and has been shown to be transmissible on seed (CABI, 2023).

5 - Economic impact:

Are there documented reports of any economic impact on the host?

Justification:

Pseudomonas viridiflava can cause bacteria canker disease in apricot (Parisi et al., 2019; Maguvu et al., 2024). The species is present in European orchard causing disease, it belongs to the Pseudomonas syringae species complex (PSSC), but its impact in disease compared to other species in the PSSC is not yet clear. Although P. viridiflava did cause cankers, Maguvu et al (2024) indicated that it seems to be a weaker pathogen of apricot compared to the other Pseudomonads isolated in this research (P syringae pv. syringae and P. cerasi). P. viridiflava was isolated from symptomatic and asymptomatic apricot tissue (Maguvu et al., 2024). P. viridiflava may very occasionally cause significant crop damage, though it is commonly isolated as a sub-population in the investigation of more vigorous pathogens (CABI, 2023).

What is the likely economic impact of the pest irrespective of its infestation source in the absence of phytosanitary measures? (= official measures)

Is the economic impact due to the presence of the pest on the named host plant for planting, acceptable to the propagation and end user sectors concerned?

Is there unacceptable economic impact caused to other hosts (or the same host with a different intended use) produced at the same place of production due to the transfer of the pest from the named host plant for planting?

Conclusion:

Not candidate

Justification:

6 - Are there feasible and effective measures available to prevent the presence of the pest on the plants for planting at an incidence above a certain threshold (including zero) to avoid an unacceptable economic impact as regards the relevant host plants?

Conclusion:

Justification:

7- Is the quality of the data sufficient to recommend the pest to be listed as a RNQP?

Conclusion:

Justification:

CONCLUSION ON THE STATUS:

Disqualified: plants for planting is not a significant pathway compared to natural spread. Economic impact acceptable when not in coinfection.

8 - Tolerance level:

Is there a need to change the Tolerance level:

Yes

Proposed Tolerance levels:

Delisting

9 - Risk management measures:

Is there a need to change the Risk management measure:

Yes

Proposed Risk management measure:

Delisting

REFERENCES:

Balestra GM, Mazzaglia A & Rossetti A (2008) Outbreak of bacterial blossom blight caused by pseudomonas viridiflava on Actinidia chinensis kiwifruit plants in Italy. Plant Disease 92(12), 1707. https://doi.org/10.1094/PDIS-92-12-1707A
CABI (2023) Pseudomonas viridiflava (bacterial leaf blight of tomato). Plantwise technical factsheet (accessed 15/Aug/2024). https://plantwiseplusknowledgebank.org/doi/10.1079/PWKB.Species.45024.
Goumas DE & Chatzaki AK (1998) Characterization and host range evaluation of Pseudomonas viridiflava from melon, blite, tomato, chrysanthemum and eggplant. European Journal of Plant Pathology 104, 181–188.
Lipps SM, Samac DA. Pseudomonas viridiflava: An internal outsider of the Pseudomonas syringae species complex. Mol Plant Pathol. 2022 Jan;23(1):3-15. doi: 10.1111/mpp.13133.
Manna S, Delgado Santander R & Zhao Y (2024) First report of Pseudomonas amygdali pv. morsprunorum causing bacterial canker in sweet cherry orchards in Washington State. Plant Disease 108(8) doi: 10.1094/PDIS-04-24-0718-PDN.
Maguvu TE, Frias RJ , Hernandez-Rosas AI, Holtz BA , Niederholzer FJA, Duncan RA , Yaghmour MA, Culumber CM, Gordon PE, Vieira FCF, Rolshausen PE, Adaskaveg JE, Burbank LP, Lindow SE, Trouillas FP (2024). Phylogenomic analyses and comparative genomics of Pseudomonas syringae associated with almond (Prunus dulcis) in California. PLoS ONE 19(4): e0297867. https://doi.org/10.1371/journal.pone.0297867
Parisi L, Morgaint B, Blanco‐Garcia J, Guilbaud C, Chandeysson C, Bourgeay JF, Moronvalle A, Brun L, Brachet ML & Morris, C. E. (2019). Bacteria from four phylogroups of the Pseudomonas syringae complex can cause bacterial canker of apricot. Plant Pathology 68(7), 1249-1258. https://bsppjournals.onlinelibrary.wiley.com/doi/pdfdirect/10.1111/ppa.13051
Sarris PF, Trantas EA, Mpalantinaki E, Ververidis F & Goumas DE (2012) Pseudomonas viridiflava, a multi host plant pathogen with significant genetic variation at the molecular level. PLoS One 7(4):e36090. doi: 10.1371/journal.pone.0036090.
Scortichini M & Morone C (1997) Apoplexy of peach trees caused by Pseudomonas viridiflava. Journal of Phytopathology 145, Issue8-9, 397-399.
Sulikowska, M. and Sobiczewski, P. (2008) Pseudomonas spp. isolated from stone fruit trees in Poland. Zemdirbyste-Agriculture 95, 166–170.