| Legend |
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| Justification for qualification based on EPPO PM 4 Standards |
| Justification for disqualification |
| Additional or non-conclusive information |
| Standard text |
NAME OF THE ORGANISM: Nepovirus cerasiferae (myrobalan latent ringspot virus) (MLRSV0)
GENERAL INFORMATION ON THE PEST
Name as submitted in the project specification (if different):
Myrobalan latent ringspot virus
Pest category:
Viruses and viroids
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:
- Candidate: Fruits (including hops) sector
Justification (if necessary):
-
2 – Status in the EU:
Is this pest already a quarantine pest for the whole EU?
No
Presence in the EU:
Yes
List of countries (EPPO Global Database):
-
Conclusion:
Candidate
Justification (if necessary):
Myrobalan latent ringspot virus has a limited geographical distribution, it is found only in the southwest of France (Dunez et al., 1976). There is no recent report of this virus naturally occurring in Prunus spp (CAB search 8/Aug/2024). As reported in EFSA (2019), it might be present but not reported in other EU MSs or outside the EU (Martelli & Uyemoto, 2011).
[In the responses to the questionnaire, CZ questioned presence of the pest in the region.]
[In the responses to the questionnaire, CZ questioned presence of the pest in the region.]
HOST PLANT N°1: Prunus salicina (PRNSC) 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):
Listed as 'Myrobalan latent ringspot nepovirus (MLRSV)' in EPPO Standard PM 4-30 Certification scheme for almond, apricot, peach and plum; and testing is recommended for P. domestica, P. insititia, P. salicina (plum), P. besseyi, P. cerasifera, P. davidiana and interspecific hybrids. However, in responses to the questionnaire, AT, CZ and PL supported deregulation because of absence in the region, pathway, economic impact and no feasible and effective measures available. Evaluation continues. A full assessment is performed on this pest.
Remark: The assessment performed covers the given host species as well as interspecific hybrids with other Prunus species.
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):
Yes
Conclusion:
Candidate
Justification:
Myrobalan latent ringspot virus (MLRSV) is a nepovirus occurring in southwestern France. It can infect several Prunus spp., but in most Prunus spp. MLRSV remains symptomless. Only in Prunus avium ‘Bing’ and in peach symptoms are induced (Dunez et al., 1976).
It is likely to be spread with plant material – like other nepoviruses -, but the virus occurs very locally. Since its original description (Dunez et al., 1971), it has not been found elsewhere. In Transylvania Romania, in 2020 and 2021, sixteen newly established commercial plum and eleven sweet cherry orchards were tested for a range of viruses, among them Myrobalan latent ringspot virus. The pathogen was not detected (Zagrai et al. 2022).
There is no information on seed transmission or transmission through nematodes (Dunez et al., 1976).
The Fruit SEWG considered that plants for planting was a significant pathway.
It is likely to be spread with plant material – like other nepoviruses -, but the virus occurs very locally. Since its original description (Dunez et al., 1971), it has not been found elsewhere. In Transylvania Romania, in 2020 and 2021, sixteen newly established commercial plum and eleven sweet cherry orchards were tested for a range of viruses, among them Myrobalan latent ringspot virus. The pathogen was not detected (Zagrai et al. 2022).
There is no information on seed transmission or transmission through nematodes (Dunez et al., 1976).
The Fruit SEWG considered that plants for planting was a significant pathway.
5 - Economic impact:
Are there documented reports of any economic impact on the host?
No
Justification:
Myrobalan latent ringspot virus (MLRSV) was first described in France in a Prunus cerasifera tree (myrobalan) showing very poor growth and reduced vigor (Dunez et al. 1971, reported in Khalili et al. 2024). Since then it seems that no damage by this virus in the field has been reported in any of its hosts. This virus has a minor economic importance due to the localized geographical area of occurrence and the fact that several Prunus spp. are infected symptomlessly, including its original host myrobalan (Prunus cerasifera).
MLRSV can cause short internodes and rosetting in peach (Prunus persica) and enations on the leaves of sweet cherry (P. avium) cv. Bing. In addition, MLRSV elicits stem pitting and graft incompatibility in diverse Prunus rootstocks, and enations in some cherry cultivars, especially Bing (Dunez et al., 1976; Desvignes et al., 1999 in Martelli & Uyemoto, 2011).
[In the responses to the questionnaire, AT and CZ questioned whether this pest was causing any damage.]
MLRSV can cause short internodes and rosetting in peach (Prunus persica) and enations on the leaves of sweet cherry (P. avium) cv. Bing. In addition, MLRSV elicits stem pitting and graft incompatibility in diverse Prunus rootstocks, and enations in some cherry cultivars, especially Bing (Dunez et al., 1976; Desvignes et al., 1999 in Martelli & Uyemoto, 2011).
[In the responses to the questionnaire, AT and CZ questioned whether this pest was causing any damage.]
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?
No
Conclusion:
Not candidate
Justification:
There are no data reporting damage in orchards at least for the last four decades.
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:
As other nepoviruses, however this virus is very rare: occurring only in southwestern France and no recent reports. In most Prunus spp. symptomless.
[In the responses to the questionnaire, CZ questioned the feasibility of testing: 'no reliable detecting methods alvailable - NGS detection possibble, but not alvailable in CR. Elisa testing is not provable - - there is a risk of cross-reaction with other viruses, especially TBRV. The detections were described in older literature resources in FR'. In CZ no sampling and testing performed for this virus on stone fruits.]
[In the responses to the questionnaire, CZ questioned the feasibility of testing: 'no reliable detecting methods alvailable - NGS detection possibble, but not alvailable in CR. Elisa testing is not provable - - there is a risk of cross-reaction with other viruses, especially TBRV. The detections were described in older literature resources in FR'. In CZ no sampling and testing performed for this virus on stone fruits.]
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: no report of economic impact under orchard conditions since its first description.
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:
- Devignes JC, Boyé R, Cornaggia D & Grasseau N (1999) Maladies à virus des arbres fruiters. Edition CTIFL, Paris.
- Dunez J, Delbos R, Desvignes JC, Marenaud C, Kuszala J & Vuittenez A (1971). Mise en evidence d'un virus de type ring spot sur Prunus cerasifera. Annales de Phytopathologie Hors Serie 117-128.
- Dunez J, Delbos R & Dupont G (1976) Myrobalan latent ringspot virus. Description Plant Viruses no. 160. https://www.dpvweb.net/dpv/showdpv/?dpvno=160
- EFSA (2019) EFSA Panel on Plant Health (PLH); Bragard C, Dehnen-Schmutz K, Gonthier P, Jacques MA, Jaques Miret JA, Justesen AF, MacLeod A, Magnusson CS, Milonas P, Navas-Cortes JA, Parnell S, Potting R, Reignault PL, Thulke HH, der Werf WV, Vicent Civera A, Yuen J, Zappalà L, Candresse T, Chatzivassiliou E, Winter S, Chiumenti M, Di Serio F, Kaluski T, Minafra A, Rubino L. List of non-EU viruses and viroids of Cydonia Mill., Fragaria L., Malus Mill., Prunus L., Pyrus L., Ribes L., Rubus L. and Vitis L. EFSA J. 2019 Sep 30;17(9):e05501. doi: 10.2903/j.efsa.2019.5501. PMID: 32626418; PMCID: PMC7009187.
- Khalili M, Candresse T, Faure C, Brans Y & Marais A (2024) Complete genome sequences of three Prunus-infecting nepoviruses: apricot latent ringspot virus, myrobalan latent ringspot virus, and a novel virus from smooth stone peach (Prunus mira Koehne). Archives of Virology 169(8), 168. https://doi.org/10.1007/s00705-024-06091-7
- Martelli GP & Uyemoto (2011) Nematode-borne viruses of stone fruits. In Virus and virus-like diseases of pome and stone fruits (eds Hadidi A., Barba M, Candresse T & Jelkmann W). American Phytopathological Society St Paul, MN, USA, pages 161-170.
- Zagrai LA, Zagrai I, Guzu GM, Rosu-Mares SD & Moldovan C (2022) Assessment of the virus infections occurrence in new established plum and sweet cherry orchards in Transylvania, Romania. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 50(2), 12734. https://doi.org/10.15835/nbha50212734