NAME OF THE ORGANISM: Onion yellow dwarf virus (OYDV00)
GENERAL INFORMATION ON THE PEST
Name as submitted in the project specification (if different to the preferred name):
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: Vegetable propagating and planting material (other than seeds) sector
Is it justified that the pest is listed at a taxonomic rank below species level?
Not relevant
Conclusion:
- Candidate: Vegetable propagating and planting material (other than seeds) sector
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 (1993); Czech Republic (2011); Denmark (1984); Estonia (1984); Finland (2011); France (1984); Germany (1993); Hungary (1992); Poland (1984); Romania (1984); United Kingdom (1993); United Kingdom/England (1994); United Kingdom/Scotland (1994)
Conclusion:
candidate
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: Allium cepa Aggregatum types (Allium ascalonicum) (ALLAS) for the Vegetable propagating and planting material (other than seeds) sector.
Origin of the listing:
2 - Vegetable seedling sector: Commission Directive 93/61/EC
Plants for planting:
Plants intended for planting
3 - Is the pest already listed in a PM4 standard on the concerned host plant?
No
Conclusion:
Evaluation continues
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:
The virus survives in shallot bulbs and is transmissible during vegetative production by Myzus persicae. It is not transmissible through seeds or pollen. So provided seedlings for transplanting or shallot bulbs are produced under protected conditions to prevent virus infection by aphids, planting material should not be infected. Therefore although seedlings can be considered a pathway it is not considered they would be a significant source compared to other pathways. For shallot sets, however, these could be potentially infected during their production if grown outside. If all other inoculum sources were removed before planting through efficient cultivations etc, then sets could be considered a significant pathway compared to other sources.
5 - Economic impact:
Are there documented reports of any economic impact on the host?
Yes
Justification:
This virus causes severe mosaic and stunting in shallots. It is often found in association with other viruses of Allium. Approximately 30% of field-grown shallot plants in Serbia showed leaf symptoms in the form of yellow stripes accompanied by leaf curling and plant stunting caused by OYDV (Milošević et al., 2015). Yield decrease of 30% to 60% are observed (Messiaen et al., 1993). Experts concluded that the pest is very important for shallot, when produced from vegetative multiplication.
What is the likely economic impact of the pest irrespective of its infestation source in the absence of phytosanitary measures? (= official measures)
Major
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?
No
Conclusion:
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?
Yes
Conclusion:
candidate
Justification:
7- Is the quality of the data sufficient to recommend the pest to be listed as a RNQP?
Yes
Conclusion:
Candidate
Justification:
CONCLUSION ON THE STATUS:
Recommended for listing as an RNQP, based on data. Impact on shallot is unacceptable when produced by vegetative multiplication.
8 - Tolerance level:
Is there a need to change the Tolerance level:
Yes
Proposed Tolerance levels:
1% tolerance, based on visual examination, with a 10% associated failure rate.
9 - Risk management measures:
Is there a need to change the Risk management measure:
Yes
Proposed Risk management measure:
(a) The crop has been inspected at least once at an appropriate time since the beginning of the last complete cycle of vegetation and no symptoms of Onion yellow dwarf virus have been seen;
or
(b) The crop has been inspected at least once at an appropriate time since the beginning of the last complete cycle of vegetation in which not more than 10% of the plants showed symptoms of Onion yellow dwarf virus, with those plants rogued out immediately and not more than 1% of plants showing symptoms seen in a final inspection.
or
(b) The crop has been inspected at least once at an appropriate time since the beginning of the last complete cycle of vegetation in which not more than 10% of the plants showed symptoms of Onion yellow dwarf virus, with those plants rogued out immediately and not more than 1% of plants showing symptoms seen in a final inspection.
REFERENCES:
- Messiaen JM, Leroux JP, Pichon M & Beyries A (1993) "les allium alimentaires reproduits par voie végétative" du labo au terrain. Edition INRA;
- Milošević D, Gvozdanović-Varga J, Ignjatov M, Nikolić Z, Vučurović I, Vučurović A & tanković I (2015) First report of Onion yellow dwarf virus infecting shallot in Serbia. Plant Disease 10, pp.1450;