| Legend |
|---|
| Justification for qualification based on EPPO PM 4 Standards |
| Justification for disqualification |
| Additional or non-conclusive information |
| Standard text |
NAME OF THE ORGANISM: Strawberry multiplier disease phytoplasma (PHYP75)
GENERAL INFORMATION ON THE PEST
Name as submitted in the project specification (if different):
Strawberry multiplier disease phytoplasma
(Multiplier disease)
(Multiplier disease)
Pest category:
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?
No
Is the pest defined at the species level or lower?:
No
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 candidate: Fruits (including hops) sector
Justification (if necessary):
The Fruit SEWG (RNQP Project part 1) decided to discard all names of phytoplasma listed in the EU Marketing Directive and to add all phytoplasma species reported from naturally infected strawberry plants. This consisted in the listing of ‘Candidatus Phytoplasma asteris’ (aster yellows phytoplasma), ‘Candidatus Phytoplasma pruni’, ‘Candidatus Phytoplasma solani’, ‘Candidatus Phytoplasma australiense’, ‘Candidatus Phytoplasma fragariae’ and the clover phyllody phytoplasma.
In the RNQP Project Part 2, it is also recommended to list the clover phyllody phytoplasma as ‘Candidatus Phytoplasma tritici'.
When responding to the questionnaire, no country supported recommendation for regulation as an RNQP. NL commented that probably several phytoplasmas were causing such symptoms. ES, EUROSEEDS, LT and NL supported that strawberry multiplier disease phytoplasma is therefore not recommended for regulation as RNQP.
Multiplier disease (MD) was first noted in Minnesota, Wisconsin, Illinois, and New York (Demaree & Marcus 1951) and has been subsequently reported and studied in Wisconsin (Sehgal and Boone 1963; Boone 1970) (cited from Converse, 1987). Jomantiene et al. (1998) described it in Florida and identified it as belonging to the clover proliferation group, 16SrVI, to subgroup VI-B 'Candidatus Phytoplasma trifolii' (Bertaccini et al., 2014). Plants of strawberry cultivars infected by MD are dwarfed and exhibit crown proliferation. Leaflets cup upwards on short, erect petioles. Runners are short and flowers are reduced in number and size, but fruit normally. It has not been reported under this name since 1998 (CAB search 30/Aug/2024).
Multiplier disease occurs rarely and is found mainly in the Great Lakes region of the United States and in British Columbia in Canada. The disease is readily detected, and infected plants can be readily rogued. Because of its rarity, it is not economically significant (Converse, 1987).
Multiplier disease is a symptom and various phytoplasmas/organisms may induce similar symptoms, or the same phytoplasmas may induce different symptoms. This all may depend on the cultivar involved, environmental factors, or the age of the plant at time of infection. It is also possible that different symptoms represent disease progression (Padovan et al., 2000). 'Candidatus Phytoplasma asteris' is also reported to cause strawberry multiplier disease (Lee et al., 2004). ‘Ca. P. trifolii’ is reported to cause similar symptoms in strawberry but is not considered to be present in strawberry in Europe. A symptom should not be a RNQP.
In the RNQP Project Part 2, it is also recommended to list the clover phyllody phytoplasma as ‘Candidatus Phytoplasma tritici'.
When responding to the questionnaire, no country supported recommendation for regulation as an RNQP. NL commented that probably several phytoplasmas were causing such symptoms. ES, EUROSEEDS, LT and NL supported that strawberry multiplier disease phytoplasma is therefore not recommended for regulation as RNQP.
Multiplier disease (MD) was first noted in Minnesota, Wisconsin, Illinois, and New York (Demaree & Marcus 1951) and has been subsequently reported and studied in Wisconsin (Sehgal and Boone 1963; Boone 1970) (cited from Converse, 1987). Jomantiene et al. (1998) described it in Florida and identified it as belonging to the clover proliferation group, 16SrVI, to subgroup VI-B 'Candidatus Phytoplasma trifolii' (Bertaccini et al., 2014). Plants of strawberry cultivars infected by MD are dwarfed and exhibit crown proliferation. Leaflets cup upwards on short, erect petioles. Runners are short and flowers are reduced in number and size, but fruit normally. It has not been reported under this name since 1998 (CAB search 30/Aug/2024).
Multiplier disease occurs rarely and is found mainly in the Great Lakes region of the United States and in British Columbia in Canada. The disease is readily detected, and infected plants can be readily rogued. Because of its rarity, it is not economically significant (Converse, 1987).
Multiplier disease is a symptom and various phytoplasmas/organisms may induce similar symptoms, or the same phytoplasmas may induce different symptoms. This all may depend on the cultivar involved, environmental factors, or the age of the plant at time of infection. It is also possible that different symptoms represent disease progression (Padovan et al., 2000). 'Candidatus Phytoplasma asteris' is also reported to cause strawberry multiplier disease (Lee et al., 2004). ‘Ca. P. trifolii’ is reported to cause similar symptoms in strawberry but is not considered to be present in strawberry in Europe. A symptom should not be a RNQP.
2 – Status in the EU:
Is this pest already a quarantine pest for the whole EU?
No
Presence in the EU:
List of countries (EPPO Global Database):
-
Conclusion:
Justification (if necessary):
HOST PLANT N°1: Fragaria (1FRAG) 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:
Justification (if necessary):
EPPO Standard PM 4/11 Certification scheme for strawberry recommends inspection and/or testing for 'strawberry green petal phytoplasma', 'lethal decline', 'aster yellows phytoplasma', 'phytoplasma yellows', 'multiplier plant' etc.
'Multiplier plant' in PM 4/11 stands for 'Strawberry multiplier disease phytoplasma'.
'Multiplier plant' in PM 4/11 stands for 'Strawberry multiplier disease phytoplasma'.
4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):
Conclusion:
Justification:
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:
Disqualified: no clear taxonomy. A symptom should not be listed as an RNQP.
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:
- Bertaccini A, Duduk B, Paltrinieri S & Contaldo N (2014) Phytoplasmas and phytoplasma diseases: a severe threat to agriculture. American Journal of Plant Sciences 5, 1763-1788.
- Boone DM (1970) Witches'-broom and multiplier diseases of strawberry, p. 25-26 In N. W. Frazier, editor. Virus diseases of small fruits and grapevines. University of California, Division of Agricultural Sciences, Berkeley, 290 p.
- Converse RH (1987) Strawberry Witches'-Broom and Multiplier Diseases. In Virus Disease of Small Fruits (ed Converse RH) Agricultural Handbook, number 631. United States Department of Agriculture, Agricultural Research Service. Pages 66-68.
- Demaree JB & Marcus CP (1951) Virus diseases of strawberries in the United States, with special reference to distribution, indexing, and insect vectors in the East. Plant Disease Reporter 35, 527-537.
- Jomantiene R, Davis RE, Maas J & Dally EL (1998) Classification of new phytoplasmas associated with diseases of strawberry in Florida, based on analysis of 16S rRNA and ribosomal protein gene operon sequences. International Journal of Systematic Bacteriology 48(1), 269-277.
- Lee IM, Gundersen-Rindal DE, Davis RE, Bottner KD, Marcone C & Seemüller E (2004) ‘Candidatus Phytoplasma asteris’, a novel phytoplasma taxon associated with aster yellows and related diseases. International Journal of Systematic and Evolutionary Microbiology 54, 1037-1048.
- Maas JL (2000) Opportunities to reduce the potential for disease infection and spread with strawberry plug plants. Acta Horticulturae 513, 409-414.
- Padovana A, Gibb K & Persley D (2000) Association of `Candidatus Phytoplasma australiense' with green petal and lethal yellows diseases in strawberry Plant Pathology 49, 362-369.
- Sehgal OP & Boone DN (1963) Multiplier disease of strawberry in Wisconsin. Plant Disease Reporter 47, 46-48.