| Legend |
|---|
| Justification for qualification based on EPPO PM 4 Standards |
| Justification for disqualification |
| Additional or non-conclusive information |
| Standard text |
NAME OF THE ORGANISM: Olivavirus flavioleae (olive leaf yellowing-associated virus) (OLYAV0)
GENERAL INFORMATION ON THE PEST
Name as submitted in the project specification (if different):
Olive leaf yellowing- associated virus (Leaf yellowing complex
disease 3)
disease 3)
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):
OLYaV is an unassigned species in the family Closteroviridae. Various studies have been published and are still in progress to define its taxonomic position (Albanese et al., 2012; Ruiz-Garcia et al., 2020). Diagnostic tests for OLYaV were so far limited to PCR-based methods targeting the HSP70h gene. Recent knowledge of the nucleotide sequence of the genome will facilitate the development of other diagnostic tests (Ruiz-Garcia et al., 2020).
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):
OLYaV seems to be one of the most widespread olive viruses: in Italy it infects more than 60% of southern Italy olive cultivars and it has also been reported in high percentages in several EPPO countries such as Israel, Lebanon, Spain, Albania, Croatia, Tunisia.
HOST PLANT N°1: Olea europaea (OLVEU) 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?
No
Conclusion:
Evaluation continues
Justification (if necessary):
Remark: Olive vein yellowing associated virus (OVYaV), Olive yellow mottling and decline associated virus (OYMDaV) and Olive leaf yellowing associated closterovirus (OLYaV) are mentioned in EPPO Standard PM 4/17 certification for olive trees and rootstocks as associated with leaf-yellowing complex disease. The Standard indicates that OLYaV is most often asymptomatic and that the presence of OVYaV as well as OYMDaV in olive is very scarce. When performing a full assessment of the RNQP status of these viruses in 2021/2022, olive certification experts considered that these yellowing viruses do not cause any unacceptable economic impact in olive. General measures in the certification scheme on the absence of symptoms were considered sufficient.
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:
OLYaV is considered to be graft transmissible.
OLYaV is widespread in olive production areas of the EPPO region. Its presence in psyllid Euphyllura olivina and unidentified mealybugs of genus Pseudococcus gave the indication that transmission by these vectors could be possible (Sabanazdovic et al., 1999). To date, no other hosts have been found for this virus (Albanese et al., 2012).
Considering the remaining uncertainties on vector transmission, experts considered that plants for planting should be considered as a significant pathway compared to others.
OLYaV is widespread in olive production areas of the EPPO region. Its presence in psyllid Euphyllura olivina and unidentified mealybugs of genus Pseudococcus gave the indication that transmission by these vectors could be possible (Sabanazdovic et al., 1999). To date, no other hosts have been found for this virus (Albanese et al., 2012).
Considering the remaining uncertainties on vector transmission, experts considered that plants for planting should be considered as a significant pathway compared to others.
5 - Economic impact:
Are there documented reports of any economic impact on the host?
Yes
Justification:
The olive leaf yellowing (OLY) disease was first recorded in Italy on cv. ‘Biancolilla’ (Savino et al., 1996) and is characterized by a bright leaf yellow discoloration (Albanese et al., 2012).
OLYaV can cause sectorial yellowing of the plant canopy (Martelli et al., 2013). OLYaV is found with high incidence and frequency, especially in Southern Italy (Fontana et al., 2019).
Evaluation of the OLYaV infections effects on olive propagation (cuttings’ rooting and grafting capacity) have been performed by Roschetti et al. (2009). This study reported the absence of negative interference of this virus on the cuttings’ rooting and on grafting capacity. Positive significant effects in grafting ability were observed on infected material only during a temperature stress, probably due to the reduced water need of infected shoots.
Cutuli et al. (2017) studied growth and physiological responses of young olive trees affected by OLYaV. Total twig length and number, trunk diameter and leaf area were significantly reduced by OLYaV, whereas no effect was detected on tree height. Water potential was lower in virus free trees due to a greater leaf area; gas exchange rates were proportional to water status. Trees affected by OLYaV partitioned more dry matter to roots and less to the main stem compared to virus-free trees.
Fontana et al. (2019) studied the effects of OLYaV on virgin olive oil yield and quality of Leccino and Ottobratica cultivars in the Calabria region (Southern Italy), including oil yield, free acidity, number of peroxides, spectrophotometric indexes, total content of chlorophylls, carotenoids and phenol, composition of the fatty acids, total tocopherols and total sterols. They suggested a no negative interference by OYLaV in oil yield and quality, except for K232 values, whereas surprisingly suggested a positive effect of virus infection on free acidity parameter.
However, despite some impact noted for few cultivars, most of the records for this virus on a large number of cultivars refer to asymptomatic findings.
OLYaV can cause sectorial yellowing of the plant canopy (Martelli et al., 2013). OLYaV is found with high incidence and frequency, especially in Southern Italy (Fontana et al., 2019).
Evaluation of the OLYaV infections effects on olive propagation (cuttings’ rooting and grafting capacity) have been performed by Roschetti et al. (2009). This study reported the absence of negative interference of this virus on the cuttings’ rooting and on grafting capacity. Positive significant effects in grafting ability were observed on infected material only during a temperature stress, probably due to the reduced water need of infected shoots.
Cutuli et al. (2017) studied growth and physiological responses of young olive trees affected by OLYaV. Total twig length and number, trunk diameter and leaf area were significantly reduced by OLYaV, whereas no effect was detected on tree height. Water potential was lower in virus free trees due to a greater leaf area; gas exchange rates were proportional to water status. Trees affected by OLYaV partitioned more dry matter to roots and less to the main stem compared to virus-free trees.
Fontana et al. (2019) studied the effects of OLYaV on virgin olive oil yield and quality of Leccino and Ottobratica cultivars in the Calabria region (Southern Italy), including oil yield, free acidity, number of peroxides, spectrophotometric indexes, total content of chlorophylls, carotenoids and phenol, composition of the fatty acids, total tocopherols and total sterols. They suggested a no negative interference by OYLaV in oil yield and quality, except for K232 values, whereas surprisingly suggested a positive effect of virus infection on free acidity parameter.
However, despite some impact noted for few cultivars, most of the records for this virus on a large number of cultivars refer to asymptomatic findings.
What is the likely economic impact of the pest irrespective of its infestation source in the absence of phytosanitary measures? (= official measures)
Minimal to Minor
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?
Yes
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:
Considering that there are few OLYaV-infected plants showing symptoms of yellowing, that the association of OLYaV with the OLY disease has not been clearly demonstrated (Albanese et al., 2012), and considering the additional symptoms and potential economic impact caused by OVYaV and OYMDaV but the very scarce reports on olive trees, experts assessed the potential economic impact of these three yellowing viruses altogether as Minimal to Minor.
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:
Not evaluated
Justification:
7- Is the quality of the data sufficient to recommend the pest to be listed as a RNQP?
No
Conclusion:
Justification:
Data quality on e.g. potential vector transmission and symptomatology is not sufficient.
CONCLUSION ON THE STATUS:
Disqualified: economic impact is considered acceptable.
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:
- Albanese G, Saponari M & Faggioli F (2012) Olive Germplasm – The Olive Cultivation, Table Olive and Olive Oil Industry in Italy. Chapter 6. Phytosanitary certification. Available at http://dx.doi.org/10.5772/51722
- Çağlayan K, Faggioli F & Barba M (2011) Viruses, phytoplasmas and diseases of unknown etiology of olive trees. In book Virus and virus-like diseases of pome and stone fruits. Chapter: 53. Publisher: The American Phytopatological Society. Editors: A. Hadidi, M. Barba, T. Candresse, W. Jelkmann
- Cutuli M, Bianco R Io, Marra FP & Caruso T (2017) Growth and physiological responses of young olive trees affected by Olive leaf yellowing associated virus. International Symposium on Physiological Principles and Their Application to Fruit Production, Geneva, New York, USA. Acta Horticulturae 1177, 165–168.
- Faggioli F & Barba M (1995) An elongated virus isolated from olive, Acta Horticulturae 386, 593–600.
- Fontana A, Piscopo A, De Bruno A, Tiberini A, Muzzalupo I & Albanese G (2019) Impact of Olive leaf yellowing associated virus on olive (Olea europaea L.) oil. European Journal of Lipid Science and Technology 1800472. doi:10.1002/ejlt.201800472
- Martelli GP, Saponari M, Bottalico G & Savino G (2013) I virus e le virosi dell'olivo. Protezione delle Colture 3, 22–29.
- Ribaldi M (1959) Preliminary observations on an infectious yellows of olive (Olea europaea var. sativa). Notiziario sulle Malattie delle Piante 47-48, 178–181.
- Roschetti A, Ferretti L, Muzzalupo I, Pellegrini F, Albanese G & Faggioli F (2009) Evaluation of the possible effect of virus infections on olive propagation. Petria 19, 18–28.
- Ruiz-García AB, Candresse T, Canales C, Morán F, de Oliveira CM, Bertolini E & Olmos A (2020) Molecular Characterization of the Complete Coding Sequence of Olive Leaf Yellowing-Associated Virus. Plants 9, 1272. doi:10.3390/plants9101272
- Sabanadzovic S, Abou-Ghanem N, La Notte P, Savino V, Scarito G & Martelli GP (1999) Partial molecular characterization and RT-PCR detection of a putative closterovirus associated with olive leaf yellowing. Journal of Plant Pathology 81, 37–45.
- Savino V, Sabanadzovic S, Scarito G, Laviola C & Martelli GP (1996) Due giallumi dell'olivo di possibile origine virale in Sicilia [Two yellows disorders of olive of possible viral origin in Sicily.]. Informatore Fitopatologico 46, 55–59.