| Legend |
|---|
| Justification for qualification based on EPPO PM 4 Standards |
| Justification for disqualification |
| Additional or non-conclusive information |
| Standard text |
NAME OF THE ORGANISM: Rhodococcus fascians (CORBFA)
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):
-
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):
Belgium (2006); Czech Republic (2006); Denmark (1992); Estonia (1992); France (1993); Germany (1993); Hungary (1992); Italy (2006); Latvia (1992); Netherlands (1993); Slovakia (2006); Sweden (1992)
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: Rubus (1RUBG) 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:
Evaluation continues
Justification (if necessary):
EPPO Standard PM 4-10 Certification scheme for Rubus recommends inspection for 'leafy gall (Rhodococcus fascians)' as appropriate to the Rubus sp. or hybrid concerned. However, in the responses to the questionnaire, SI supported deregulation in the EU, considering that economic impact was acceptable. Evaluation continues on this criteria.
4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):
?
Conclusion:
Justification:
Rhodococcus fascians can infect at least 164 species in 43 plant families (Putnam & Miller, 2007; Stes et al, 2011). The range of susceptible plants is exceptionally broad, including monocots and dicots, woody as well as herbaceous plants (Putnam & Miller, 2007). Leafy gall was reported on roots of red raspberry in Scotland in 1977 (Jones et al., 1977), but has not been reported on raspberry since (Putnam, 2017).
R. fascians is a phylloplane bacterium which primarily resides on the aboveground part of the plant, producing a slime layer for protection (Cornelis et al., 2001). R. fascians can survive and proliferate as an epiphyte on the plant surface for months prior to initiating pathogenesis and symptom development (Dhandapani et al., 2018; Dhaouadi et al., 2020).
The use of planting material originating from contaminated stock is the main source of spread in e.g. chrysanthemum (Lacey, 1936; Baker, 1950; Oduro, 1975), Schizanthus retusus (Lacey, 1939) and lilies (Miller et al., 1980). High incidence of disease in lily nurseries occurred when crop rotation was neglected, allowing abnormally high pathogen populations in the soil, and when increased mechanization in commercial bulb growing left large amounts of diseased plant material in the soil after harvesting (Miller et al., 1980).
Reports on survival of R. fascians in soil vary: the bacterium has been reported to last for at least 3 months (Oduro, 1975), more than 1 year (Digat, 1977) and 4-5 years (Faivre-Amiot, 1967, cited from CABI, 2022). The long-term survival of R. fascians in natural environments has been attributed to their ability to tolerate prolonged nutrient starvation (Boylen & Mulks, 1978). Survival on rotation crops has been indicated (Baker, 1950; cited from CABI, 2022).
Digat (1977) reported on the spread of the bacteria through irrigation water and contaminated soil.
Water is important for the dispersal of R. fascians, as it is for other bacterial diseases. Growers have reported an increased incidence of symptomatic plants in greenhouse benches which are flood irrigated, which suggests that it is carried by irrigation water. Splash from overhead irrigation or rain is also likely to be important in short distance dispersal of the pathogen (Putnam & Miller, 2007).
Although there is some evidence that the pathogen is seedborne, the main source of inoculum is probably contaminated planting material (Lacey, 1936, 1939; Baker, 1950; Digat, 1977; Muller, 1979; Miller et al., 1980, cited from CABI, 2022).
There is lack of data regarding raspberry plants for planting as a pathway.
R. fascians is a phylloplane bacterium which primarily resides on the aboveground part of the plant, producing a slime layer for protection (Cornelis et al., 2001). R. fascians can survive and proliferate as an epiphyte on the plant surface for months prior to initiating pathogenesis and symptom development (Dhandapani et al., 2018; Dhaouadi et al., 2020).
The use of planting material originating from contaminated stock is the main source of spread in e.g. chrysanthemum (Lacey, 1936; Baker, 1950; Oduro, 1975), Schizanthus retusus (Lacey, 1939) and lilies (Miller et al., 1980). High incidence of disease in lily nurseries occurred when crop rotation was neglected, allowing abnormally high pathogen populations in the soil, and when increased mechanization in commercial bulb growing left large amounts of diseased plant material in the soil after harvesting (Miller et al., 1980).
Reports on survival of R. fascians in soil vary: the bacterium has been reported to last for at least 3 months (Oduro, 1975), more than 1 year (Digat, 1977) and 4-5 years (Faivre-Amiot, 1967, cited from CABI, 2022). The long-term survival of R. fascians in natural environments has been attributed to their ability to tolerate prolonged nutrient starvation (Boylen & Mulks, 1978). Survival on rotation crops has been indicated (Baker, 1950; cited from CABI, 2022).
Digat (1977) reported on the spread of the bacteria through irrigation water and contaminated soil.
Water is important for the dispersal of R. fascians, as it is for other bacterial diseases. Growers have reported an increased incidence of symptomatic plants in greenhouse benches which are flood irrigated, which suggests that it is carried by irrigation water. Splash from overhead irrigation or rain is also likely to be important in short distance dispersal of the pathogen (Putnam & Miller, 2007).
Although there is some evidence that the pathogen is seedborne, the main source of inoculum is probably contaminated planting material (Lacey, 1936, 1939; Baker, 1950; Digat, 1977; Muller, 1979; Miller et al., 1980, cited from CABI, 2022).
There is lack of data regarding raspberry plants for planting as a pathway.
5 - Economic impact:
Are there documented reports of any economic impact on the host?
No
Justification:
Plants infected with R. fascians can show leafy galls, aerial malformations, such as stunting, deformed leaves, witches’ brooms, and fasciated shoots. R. fascians is unique among the hyperplasia-inducing bacteria because it provokes differentiated galls (leafy galls), whereas other gall-inducing bacteria (e.g. Agrobacterium tumefaciens) produce undifferentiated tissues (Stes et al., 2011). Virulence in R. fascians is controlled by genes on a linear plasmid and on the chromosome. Isolates lacking virulence genes promote beneficial plant growth. Acquisition of a virulence plasmid is sufficient for transition from a beneficial symbiont to a plant pathogen (Savoy et al., 2017).
Leafy gall was reported on roots of red raspberry in Scotland in 1977 but has not been reported on raspberry since (Jones et al., 1977; Putnam, 2017).
Leafy gall was reported on roots of red raspberry in Scotland in 1977 but has not been reported on raspberry since (Jones et al., 1977; Putnam, 2017).
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?
No
Conclusion:
Not candidate
Justification:
Remark: The Fruit SEWG did not consider potential indirect economic impact to other species since the pest was only listed on Rubus in current EU regulation.
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:
Sanitation is very important: no infected plant residue, disinfect tools, clean soil, clean pots and trays
Healthy propagation material (using disease free stock, not taking cuttings from infected plants), but Rubus spp. seem not to be an important host for R. fascians.
Using sterilised soil.
Avoid growing on the floor.
Avoiding long leaf wetness durations
(Pacific Northwest Pest Management Handbooks, 2024).
Healthy propagation material (using disease free stock, not taking cuttings from infected plants), but Rubus spp. seem not to be an important host for R. fascians.
Using sterilised soil.
Avoid growing on the floor.
Avoiding long leaf wetness durations
(Pacific Northwest Pest Management Handbooks, 2024).
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: rarely reported on raspberry
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:
- Baker KF (1950) Bacterial fasciation disease of ornamental plants in California. Plant Disease Reporter 34, 121-126.
- CABI (2022) Rhodococcus fascians (leafy gall). PlantWise (accessed 23/Aug/2024). https://plantwiseplusknowledgebank.org/doi/full/10.1079/pwkb.species.15332
- Cornelis K, Ritsema T, Nijsse J, Holsters M, Goethals K & Jaziri M (2001). The plant pathogen Rhodococcus fascians colonizes the exterior and interior of the aerial parts of plants. Molecular Plant-Microbe Interaction 14, 599–608.
- Dhandapani P, Song J, Novak O & Jameson PE (2018) Both epiphytic and endophytic strains of Rhodococcus fascians influence transporter gene expression and cytokinins in infected Pisum sativum L. seedlings. Plant Growth Regulation, 85, 231-242.
- Depuydt S, de Veylder L, Holsters M & Vereecke D (2009) Eternal youth, the fate of developing Arabidopsis leaves upon Rhodococcus fascians infection. Plant Physiology 149, 1387–1398.
- Digat B (1977) New aspects of the control of geranium bacterial diseases. Pepinieristes Horticulteurs Maraichers 174, 17-23.
- Dhaouadi S, Mougou AH & Rhouma A (2020). The plant pathogen Rhodococcus fascians. History, disease symptomatology, host range, pathogenesis and plant–pathogen interaction. Annals of Applied Biology 177(1), 4-15.
- Faivre-Amiot A (1967) Quelques observations sur la presence de Corynebacterium fascians (Tilford) Dowson dans les cultures maraicheres et florales en France. Phytiatrie-Phytopharmacie 16, 165-176.
- Jones GE, Catton FW & Bateson M (1977) Root galls on raspberry. Plant Pathology 26(2), 96-97.
- Lacey MS (1936) Further studies on a bacterium causing fasciation of sweet peas. Annals of Applied Biology 23, 743-751.
- Lacey MS (1939) Studies on a bacterium associated with leafy galls, fasciations and 'cauliflower' disease of various plants. Part III. Further isolations, inoculation experiments and cultural studies. Annals of Applied Biology 26, 262-278.
- Miller HJ, Janse JD, Kamerman W & Muller PJ (1980) Recent observations on leafy gall in Liliaceae and some other families. Netherlands Journal of Plant Pathology 86(2), 55-68
- Pacific Northwest Pest Management Handbooks (2024). Greenhouse Plants, Ornamental-Shoot Proliferation and Leafy Gall. Available: Greenhouse Plants, Ornamental-Shoot Proliferation and Leafy Gall | Pacific Northwest Pest Management Handbooks (pnwhandbooks.org). Accessed: 18/10/2024.
- Putnam ML & Miller ML (2007). Rhodococcus fascians in herbaceous perennials. Plant Disease 91(9), 1064-1076.
- Putnam ML (2017) Leafy gall. In Compendium of Raspberry and Blackberry Diseases and Pests (eds Martin RR, Ellis MA, Williamson B & Williams R). American Phytopathological Society, St Paul, MN, USA. pages 66-67.
- Vereecke, D., Temmerman, W., Jaziri, M., Holsters, M., and Goethals, K. 2003. Toward an understanding of the Rhodococcus fascians- plant interaction. Plant Microbe Interactions. Vol 6. G. Stacy and N. Kean, eds. American Phytopathological Society, St. Paul, MN.
- Vereecke D, Burssens S, Simón-Mateo C, Inzé D, van Montagu M, Goethals K & Jaziri M (2000) The Rhodococcus fascians plant interaction: Morphological traits and biotechnical applications. Planta 210, 241–251.
- Savory EA, Fuller SL, Weisberg AJ, Thomas WJ, Gordon MI, Stevens DM, Creason AL, Belcher MS, Serdani M, Wiseman MS, Grünwald NJ, Putnam ML & Chang JH (2017) Evolutionary transitions between beneficial and phytopathogenic Rhodococcus challenge disease management. eLife 6:e30925.
- Stes E, Vandeputte OM, El Jaziri M, Holsters M & Vereecke D (2011) A successful bacterial coup d'état: how Rhodococcus fascians redirects plant development. Annual review of phytopathology 49(1), 69-86