| Legend |
|---|
| Justification for qualification based on EPPO PM 4 Standards |
| Justification for disqualification |
| Additional or non-conclusive information |
| Standard text |
NAME OF THE ORGANISM: Pospiviroid exocortiscitri (Citrus exocortis viroid) (CEVD00)
GENERAL INFORMATION ON THE PEST
Name as submitted in the project specification (if different):
Citrus exocortis viroid
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:
- Not evaluated: Fruits (including hops) sector
Justification (if necessary):
Overall, methods for reliable detection and identification/discrimination of pospiviroids are available, although their high sensitivity implies the risk of false-positive reactions because of cross-contamination. These techniques are already widely used by EU MS as indicated by the answers received to the questionnaire sent by EFSA (EFSA PLH, 2011).
Remarks:
- Fortunella is considered to be a synonym of Citrus by some authors. Using SSRs markers, Fortunella clusters within the genus Citrus (Barkley et al., 2006). These should be considered the same genus.
- Poncirus is considered to be a synonym of Citrus by some authors, and is categorized as such in EPPO GD. However, when using SSRs markers, Poncirus is a sister genus to Citrus (Barkley et al., 2006). In addition, one chromosomal marker can be used to distinguish Poncirus from Citrus species (Brasileiro Vidal et al., 2007). Whether to consider these as synonym or not is still a matter of debate.
Remarks:
- Fortunella is considered to be a synonym of Citrus by some authors. Using SSRs markers, Fortunella clusters within the genus Citrus (Barkley et al., 2006). These should be considered the same genus.
- Poncirus is considered to be a synonym of Citrus by some authors, and is categorized as such in EPPO GD. However, when using SSRs markers, Poncirus is a sister genus to Citrus (Barkley et al., 2006). In addition, one chromosomal marker can be used to distinguish Poncirus from Citrus species (Brasileiro Vidal et al., 2007). Whether to consider these as synonym or not is still a matter of debate.
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):
Austria (2010); Belgium (2014); Croatia (2020); Cyprus (2011); Czech Republic (2010); France (1979); France/Corse (1994); Germany (2008); Greece (2020); Greece/Kriti (2020); Italy (2011); Italy/Sicilia (1994); Italy/Sardegna (1994); Netherlands (2008); Portugal (2006); Slovenia (2011); Spain (1979)
Conclusion:
Justification (if necessary):
Data of the presence of this pest on the EU territory are available in EPPO Global Database (https://gd.eppo.int/).
HOST PLANT N°1: Citrus (1CIDG) 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:
Qualified
4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):
Conclusion:
Justification:
CEVd is not reported to be vector or seed transmitted (Belabess et al., 2021). When testing seed transmission, all Citrus plants produced were tested negative (Bitters et al., 1954).
5 - Economic impact:
Are there documented reports of any economic impact on the host?
Justification:
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:
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:
Recommended for listing as an RNQP, based on EPPO PM4 Standards.
8 - Tolerance level:
Is there a need to change the Tolerance level:
No
Proposed Tolerance levels:
9 - Risk management measures:
Is there a need to change the Risk management measure:
Yes
Proposed Risk management measure:
The Fruit SEWG supported that testing of CAC seed-producing mother plants should not be required for viruses that are not known to be seed-transmitted, as is the case for CEVd.
REFERENCES:
- Barkley NA, Roose ML, Krueger RR, Federici CT (2006) Assessing genetic diversity and population structure in a citrus germplasm collection utilizing simple sequence repeat markers (SSRs). Theor Apple Genet. 112(8), 1519-31.
- Belabess Z, Radouane N, Sagouti T, Tahiri A & Lahlali R (2021) A Current Overview of Two Viroids Prevailing in Citrus Orchards: Citrus Exocortis Viroid and Hop Stunt Viroid. Citrus - Research, Development and Biotechnology. IntechOpen. DOI: http://dx.doi.org/10.5772/intechopen.95914
- Bitters, Brusca & Dukeshire (1954) Citrus Leaves 34, 8
- Brasileiro-Vidal AC, Dos Santos-Serejo JA, Soares Filho Wdos S, Guerra M. (2007) A simple chromosomal marker can reliably distinguishes Poncirus from Citrus species. Genética 129(3), 273-9.
HOST PLANT N°2: Citrus (Fortunella) (1FOLG) 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:
Qualified
4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):
Conclusion:
Justification:
Citrus spp. is a major host for CEVd (Diener, 1979). Fortunella is reported as a host plant for CEVd (Lin et al., 2015).
CEVd is not reported to be vector or seed transmitted (Belabess et al., 2021). When testing seed transmission, all Citrus plants produced were tested negative (Bitters et al., 1954).
CEVd is not reported to be vector or seed transmitted (Belabess et al., 2021). When testing seed transmission, all Citrus plants produced were tested negative (Bitters et al., 1954).
5 - Economic impact:
Are there documented reports of any economic impact on the host?
Justification:
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:
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:
Recommended for listing as an RNQP, based on EPPO PM4 Standards.
8 - Tolerance level:
Is there a need to change the Tolerance level:
No
Proposed Tolerance levels:
9 - Risk management measures:
Is there a need to change the Risk management measure:
Yes
Proposed Risk management measure:
The Fruit SEWG supported that testing of CAC seed-producing mother plants should not be required for viruses that are not known to be seed-transmitted, as is the case for CEVd.
REFERENCES:
- Barkley NA, Roose ML, Krueger RR, Federici CT (2006) Assessing genetic diversity and population structure in a citrus germplasm collection utilizing simple sequence repeat markers (SSRs). Theor Apple Genet. 112(8), 1519-31.
- Belabess Z, Radouane N, Sagouti T, Tahiri A & Lahlali R (2021) A Current Overview of Two Viroids Prevailing in Citrus Orchards: Citrus Exocortis Viroid and Hop Stunt Viroid. Citrus - Research, Development and Biotechnology. IntechOpen. DOI: http://dx.doi.org/10.5772/intechopen.95914
- Bitters, Brusca & Dukeshire (1954) Citrus Leaves 34, 8
- Brasileiro-Vidal AC, Dos Santos-Serejo JA, Soares Filho Wdos S, Guerra M. (2007) A simple chromosomal marker can reliably distinguishes Poncirus from Citrus species. Genética 129(3), 273-9.
- Lin CY, Wu ML, Shen TL, Yeh HH & Hung TH (2015) Multiplex detection, distribution, and genetic diversity of Hop stunt viroid and Citrus exocortis viroid infecting citrus in Taiwan. Virology Journal 12(11). Available at http://www.virologyj.com/content/12/1/11