| 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: Candidatus Phytoplasma prunorum (PHYPPR)
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:
- Candidate: Fruits (including hops) sector
Justification (if necessary):
For the Fruit and ornamental sectors: Candidatus phytoplasma prunorum has been detected frequently on Prunus armeniaca, P. salicina, P. domestica, P. persica and more rarely on P. amygdalus (Cieślińska, 2011). Wild species of P. spinosa and P. cerasifera are frequently host plants. This diversity is supporting a listing at the Genus level for Prunus.
For the Forestry sector: Prunus avium is the only host of the Prunus genus listed in Annex I of EU Directive 1999/105. However experts also considered during the evaluation other Prunus species, since other species are more susceptible to the disease and could also be grown in forest nurseries.
For the Forestry sector: Prunus avium is the only host of the Prunus genus listed in Annex I of EU Directive 1999/105. However experts also considered during the evaluation other Prunus species, since other species are more susceptible to the disease and could also be grown in forest nurseries.
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 (2021); Belgium (2012); Bulgaria (2012); Croatia (2012); Czech Republic (2012); France (2012); France/Corse (2012); Germany (2019); Greece (2012); Hungary (2023); Italy (2012); Italy/Sardegna (2012); Poland (2012); Romania (2012); Slovenia (2018); Spain (2015)
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/). During the RNQP Project - part 1, this pest was a candidate for the RNQP status according to the IIA2AWG.
Comment by forestry experts during RNQP Project - part 1: Very limited number of analyses were performed on Prunus avium, but besides older data, new reports are confirmed from Poland (Cieslinska 2015), Czech Republic (Ludvikova et al., 2011) and Hungary (Tarcali & Kovics, 2012). Since no targeted surveys of CPp infection on Prunus avium are undertaken, the distribution of CPp in Europe is unclear and suspected to be underestimated.
Comment by forestry experts during RNQP Project - part 1: Very limited number of analyses were performed on Prunus avium, but besides older data, new reports are confirmed from Poland (Cieslinska 2015), Czech Republic (Ludvikova et al., 2011) and Hungary (Tarcali & Kovics, 2012). Since no targeted surveys of CPp infection on Prunus avium are undertaken, the distribution of CPp in Europe is unclear and suspected to be underestimated.
HOST PLANT N°1: Prunus (1PRNG) 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, except seeds
3 - Is the pest already listed in a PM4 standard on the concerned host plant?
Yes
Conclusion:
Evaluation continues
Justification (if necessary):
Remark: the assessment performed also covers 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:
Plants for planting are an efficient pathway. Pathogen concentration and distribution in the trees is fluctuant in space and during the year. Wild tolerant hosts are an important source of infection (Seljak and Rot, 2013) and are present in most of the regions producing stone fruit. Vector transmission is a pathway, especially in regions where the vector Cacopsylla pruni is present. In these regions vector transmission might be the main pathway, but it is still important, even in these regions, to delay the occurrence of symptoms and damage. Experts concluded that plants for planting are a significant pathway compared to other pathways.
5 - Economic impact:
Are there documented reports of any economic impact on the host?
Yes
Justification:
The phytoplasma is present in the EU area. Prunus armeniaca and japanese plums (P. salicina) are particularly impacted as this phytoplasma can lead to the mortality of the plants (ANSES, 2012). It causes substantial economic losses due to tree decline, reduction in fruit weight and quality. Economic incidence is less important for P. persica, P. amygdalus and P. domestica. In France, in the department Pyrenees-Orientales, about 80 % of the mortality and decline observed on
apricot is due to ESFY and the production losses associated with ESFY in Italian plum orchards reach up to 40 % in Japanese plum. The economic incidence, however, depends on the susceptibility of the Prunus species, cultivars and varieties and the strain virulence. The disease is reported as “economically very important” and “severe” by different authors in major stone-fruit-growing areas of Europe (Prima phacie, 2012).
apricot is due to ESFY and the production losses associated with ESFY in Italian plum orchards reach up to 40 % in Japanese plum. The economic incidence, however, depends on the susceptibility of the Prunus species, cultivars and varieties and the strain virulence. The disease is reported as “economically very important” and “severe” by different authors in major stone-fruit-growing areas of Europe (Prima phacie, 2012).
What is the likely economic impact of the pest irrespective of its infestation source in the absence of phytosanitary measures? (= official measures)
Medium
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
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:
Candidate
Justification:
Crop losses and tree decline cause an unacceptable economic impact.
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:
Epidemiological data is lacking on the presence and impact of ESFY in certain regions (Steffek et al., 2012). However ‘Ca. P. prunorum’ is spread in most stone producing areas of Central and Southern Europe, where it has a substantial impact on apricots, Japanese plums and peaches.
CONCLUSION ON THE STATUS:
Recommended for listing as an RNQP during the RNQP Project part 1, based on data.
8 - Tolerance level:
Is there a need to change the Tolerance level:
No, for tolerance levels of propagating material (Yes, for the tolerance level for basic material in the field).
Proposed Tolerance levels:
Zero tolerance approach for propagating material, based on visual examination.
The Fruit SEWG agreed that a tolerance level in the field at 0% for basic was too strict since production of basic material is done under outdoor conditions, but did not propose a particular threshold.
The Fruit SEWG agreed that a tolerance level in the field at 0% for basic was too strict since production of basic material is done under outdoor conditions, but did not propose a particular threshold.
9 - Risk management measures:
Is there a need to change the Risk management measure:
Yes
Proposed Risk management measure:
Non-certified material (‘CAC’):
(A) Derived from mother plants which have been inspected and found free from symptoms of 'Candidatus Phytoplasma prunorum'. In the case of Prunus domestica rootstocks, it should derive from mother plants that have been tested within the previous 3 years and found free from the pest;
AND
(B) (a) Plants produced in areas known to be free from 'Candidatus Phytoplasma prunorum';
or
(b) Plants in the site of production showing symptoms during inspections at appropriate times during the last growing season, be rogued out and destroyed immediately.
Pre-basic, Basic and Certified: Additional measures could include
• Cultivation under insect-proof conditions (pre-basic);
• Isolation of mother plants from host plants of the pest and the vector, including uncultivated plants;
• Testing of candidate trees for mother plants;
• Mother plants in protected cultivation - retesting of all plants (pre-basic) or a representative sample (basic and certified) at least every 15 years;
• Other mother plants - testing of a representative sample (basic and certified) at least every 3 years;
• More testing in case of finding of an infection, including testing of all mother plants in the production site;
• Regular testing of mother plants in the case of Prunus domestica rootstocks in which symptoms cannot be seen.
In RNQP Project part 1, a 2% threshold was also applicable to ‘Candidatus Phytoplasma pyri’ in the recommendation by the Fruit SEWG. However, in 2021, EU regulation for ‘Ca. P. Pyri’, option B)c) was replaced 2021 by:
(B)(c) the plants in the site of production and any plants in the immediate vicinity, which have shown symptoms of Candidatus Phytoplasma pyri during visual inspections at appropriate times during the last three growing seasons, have been rogued out and destroyed immediately.
During the RNQP Project part 2, the Fruit SEWG recommended to increase the testing frequency of the mother plants (every 3 years instead of 5) but to remove testing in the site of production itself for CAC material (see measures) based on the following considerations. A high level of infection in the nursery will be due to a problem of infection of the mother plants (not from the environment), Prunus plants are generally sold after one year (which would not be enough time to observe the symptoms) and some level of infection from the environment will occur (remark: treatments of the vector would work to avoid the vector population building up in the nursery, but not to protect against infections by the vector arriving in the nursery when migrating from wild plums to conifers, which is the main issue for peach and apricot).
(A) Derived from mother plants which have been inspected and found free from symptoms of 'Candidatus Phytoplasma prunorum'. In the case of Prunus domestica rootstocks, it should derive from mother plants that have been tested within the previous 3 years and found free from the pest;
AND
(B) (a) Plants produced in areas known to be free from 'Candidatus Phytoplasma prunorum';
or
(b) Plants in the site of production showing symptoms during inspections at appropriate times during the last growing season, be rogued out and destroyed immediately.
Pre-basic, Basic and Certified: Additional measures could include
• Cultivation under insect-proof conditions (pre-basic);
• Isolation of mother plants from host plants of the pest and the vector, including uncultivated plants;
• Testing of candidate trees for mother plants;
• Mother plants in protected cultivation - retesting of all plants (pre-basic) or a representative sample (basic and certified) at least every 15 years;
• Other mother plants - testing of a representative sample (basic and certified) at least every 3 years;
• More testing in case of finding of an infection, including testing of all mother plants in the production site;
• Regular testing of mother plants in the case of Prunus domestica rootstocks in which symptoms cannot be seen.
In RNQP Project part 1, a 2% threshold was also applicable to ‘Candidatus Phytoplasma pyri’ in the recommendation by the Fruit SEWG. However, in 2021, EU regulation for ‘Ca. P. Pyri’, option B)c) was replaced 2021 by:
(B)(c) the plants in the site of production and any plants in the immediate vicinity, which have shown symptoms of Candidatus Phytoplasma pyri during visual inspections at appropriate times during the last three growing seasons, have been rogued out and destroyed immediately.
During the RNQP Project part 2, the Fruit SEWG recommended to increase the testing frequency of the mother plants (every 3 years instead of 5) but to remove testing in the site of production itself for CAC material (see measures) based on the following considerations. A high level of infection in the nursery will be due to a problem of infection of the mother plants (not from the environment), Prunus plants are generally sold after one year (which would not be enough time to observe the symptoms) and some level of infection from the environment will occur (remark: treatments of the vector would work to avoid the vector population building up in the nursery, but not to protect against infections by the vector arriving in the nursery when migrating from wild plums to conifers, which is the main issue for peach and apricot).
Justification (if necessary):
Remarks from RNQP Project part 1: 2% failure rate is a mean of proposals submitted within replies to the RNQP Questionnaire. Mother plants of CAC material should be inspected. There is a risk of Prunus spinosa (asymptomatic) being in the environment. Destroying contaminated plants in the immediate vicinity would be useful; however it is difficult to apply for non-quarantine pests. Prunus domestica rootstocks are asymptomatic.
During RNQP Project part 1, experts discussed the ratio cost/benefit of a more systematic testing of CAC mother plants: This would allow detection of asymptomatic plants. However, this was counterbalanced by the difficulty of testing (testing of the roots would be more reliable, but not practical) and by the risk of reinfestation in case of high vector pressure. No consensus was reached within the core-HEWGplus on the added value of such a more systematic testing, in the context of the RNQP status.
During RNQP Project part 1, experts discussed the ratio cost/benefit of a more systematic testing of CAC mother plants: This would allow detection of asymptomatic plants. However, this was counterbalanced by the difficulty of testing (testing of the roots would be more reliable, but not practical) and by the risk of reinfestation in case of high vector pressure. No consensus was reached within the core-HEWGplus on the added value of such a more systematic testing, in the context of the RNQP status.
REFERENCES:
- ANSES (2012) Rapport d'expertise collective. Groupe de travail "ARP phytoplasmes des arbres fruitiers". Available at https://www.anses.fr/fr/system/files/SVEG2011sa0137Ra.pdf;
- EU COM (2016) Recommendation of the Working Group on the Annexes of the Council Directive 2000/29/EC – Section II – Listing of Harmful Organisms as regards the future listing of Apricot chlorotic leafroll mycoplasma;
- Koncz LS, Petróczy M, Pénzes B, Ladányi M, Palkovics L, Gyócsi P, Nagy G, Ágoston J & Fail J (2023) Detection of ‘Candidatus Phythoplasma prunorum’ in Apricot Trees and its Associated Psyllid Samples. Agronomy, 13(1), 199. https://doi.org/10.3390/agronomy13010199
- Marie-Jeanne V, Bonnot F, Thébaud G, Peccoud J, Labonne G & Sauvion N (2020) Multi-scale spatial genetic structure of the vector-borne pathogen ‘Candidatus Phytoplasma prunorum’ in orchards and in wild habitats. Scientific Reports, 10(1), 5002. https://doi.org/10.1038/s41598-020-61908-0;
- Mehle N, Ravnikar M, Seljak G, Knapic V, Dermastia M (2011) The most widespread phytoplasmas, vectors and measures for disease control in Slovenia. Phytopathogenic Mollicutes 1: 65- 76. Available at: http://www.kmetijskizavod-ng.si/priponke/OVR/fitoplazme_slovenia.pdf;
- Nečas T, Kiss T, Eichmeier A, Nečasová J & Ondrášek I (2018) The effect of phytoplasma disease caused by ‘Candidatus Phytoplasma prunorum’ on the phenological and pomological traits in apricot trees. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 46(1):107-114. https://doi.org/10.15835/nbha46110879$;
- Prima phacie (2012) Pest risk assessment for the European Community plant health: A comparative approach with case studies. External scientific report by group of authors: http://www.efsa.europa.eu/fr/supporting/doc/319e.pdf;
- Seljak G, Rot M (2013) Preučevanje bionomije češpljeve bolšice (Cacopsylla pruni) na Primorskem. Zbornik predavanj in referatov 11. slovenskega posvetovanja o varstvu rastlin z mednarodno udeležbo = Lectures and papers presented at the 11th Slovenian Conference on Plant Protection with International Participation, Bled, 5.–6. marec 2013 p.: 89-95. Available at http://dvrs.bf.uni-lj.si/spvr/2013/17Seljak.pdf;
- Steffek R, Foliak S, Sauvion N, Labonne G, MacLeod A (2012) Distribution of ‘Candidatus Phytoplasma prunorum’ and its vector Cacopsylla pruni in European fruit-growing areas: a review. EPPO Bulletin 42, 191-202;