| Legend |
|---|
| Justification for qualification based on EPPO PM 4 Standards |
| Justification for disqualification |
| Additional or non-conclusive information |
| Standard text |
NAME OF THE ORGANISM: Verticillium alboatrum sensu lato {Verticillium albo-atrum} (VERTAA)
GENERAL INFORMATION ON THE PEST
Name as submitted in the project specification (if different):
Verticillium albo-atrum
Pest category:
Fungi
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):
V. albo-atrum was recently split into three species, V. albo-atrum sensu stricto (infecting mainly potato), V. alfalfae (infecting alfalfa) and V. nonalfalfae (infecting hops and other crops), for which reliable detection and identification methods exist for each one (EU COM, 2016). For this reason the evaluation of the pest continues in referring to Verticillium albo-atrum sensu lato.
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 (2014); Belgium (2015); Bulgaria (1993); Croatia (1996); Cyprus (2011); Czech Republic (2011); Denmark (2019); Estonia (1986); Finland (2011); France (1993); Germany (1993); Greece (1986); Greece/Kriti (1986); Hungary (1988); Ireland (1986); Italy (1986); Italy/Sicilia (1986); Italy/Sardegna (1986); Latvia (1986); Lithuania (1986); Luxembourg (1992); Netherlands (2022); Poland (1986); Portugal (1986); Romania (1986); Slovenia (2017); Spain (2021); Sweden (1988)
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/). Based on the NPPO answers to the EFSA questionnaire and the EPPO Global Database (2014), V. albo-atrum sensu lato is reported to be present in most of the EU MSs (EFSA, 2014).
Remark: V. nonalfalfae is currently known from Canada, the USA (IL, PA), China, Cuba, Japan and Middle Asia. The distribution of V. nonalfalfae in the EU is not yet clear due to the recent re-classification, but it can be assumed that its distribution will at least reflect the Verticillium wilt disease of hops, due to V. nonalfalfae being the main causal species (V. dahliae is sometimes isolated). This species also infects a number of other widely grown hosts such as cotton, petunia, spinach, lucerne, tomato and potato (EU COM, 2016).
Remark: V. nonalfalfae is currently known from Canada, the USA (IL, PA), China, Cuba, Japan and Middle Asia. The distribution of V. nonalfalfae in the EU is not yet clear due to the recent re-classification, but it can be assumed that its distribution will at least reflect the Verticillium wilt disease of hops, due to V. nonalfalfae being the main causal species (V. dahliae is sometimes isolated). This species also infects a number of other widely grown hosts such as cotton, petunia, spinach, lucerne, tomato and potato (EU COM, 2016).
HOST PLANT N°1: Malus (1MABG) 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, including seeds
3 - Is the pest already listed in a PM4 standard on the concerned host plant?
No
Conclusion:
Evaluation continues
Justification (if necessary):
Remark: Inspection for ' Verticillium spp.' recommended in EPPO Standard PM 4-27 Pathogen-tested material of Malus, Pyrus and Cydonia.
4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):
?
Conclusion:
Justification:
Verticillium albo-atrum s.l. occurs on numerous economically important plant species. The most prominent hosts are lucerne (Verticillium alfalfae), potato (Verticillium albo-atrum sensu stricto), hop and tomato (Verticillium nonalfalfae). In addition to the main economic hosts, V. albo-atrum s.l. may also attack crops which are more commonly affected by V. dahliae, such as strawberries (Fragaria ananassa), raspberries (Rubus idaeus), plums (Prunus domestica), tobacco (Nicotiana tabacum) and various ornamental species (see, for example, Koike, 1988); citrus and pome fruits, however, are the exception (Smith et al. 1988).
The natural host range of V. albo-atrum s.l. is narrower than that of Verticillium dahliae. However, under experimental conditions, V. albo-atrum can cause severe symptoms in plants in which it never (or rarely) causes disease naturally (Hou et al., 1995; CABI, 2021).
Compared with the microsclerotia of Verticillium dahliae, the dark, resting mycelium of V. albo-atrum has limited powers of survival and, for herbaceous hosts, loses viability too rapidly for it to be a major inoculum source in proper crop rotation (McKeen & Thorpe, 1973, 1981; Keinath & Millar, 1986); although in woody-host tissues survival may extend up to 4 years (Sewell & Wilson, 1966). The colonization of dicotyledonous weeds, rotation crops and ‘volunteer’ potato plants may contribute to bridging the period between susceptible crops (Heale & Isaac, 1963; Skadow, 1969; Celetti et al., 1990; cited in CABI, 2021). In hop gardens the pathogen can be disseminated in diseased leaves which absciss prematurely, or by cultivation operations which move infected debris. The pathogen can be disseminated with infected planting material e.g. in hops and either within potato seed tubers or as a surface contaminant of the tubers (Beckman et al., 1969; Sampson, 1980; cited in CABI).
V. albo-atrum is almost entirely limited to cool, temperate regions, although it does occur locally on potatoes at high altitude in the tropics (Turkensteen, 1987) and there are reports of a high-temperature strain affecting lucerne in southern California, USA (Howell & Erwin, 1995; Erwin & Howell, 1998). Most of the reports that were used by CMI (1986) are of V. dahliae: that distribution is therefore misleading (CABI, 2021)
Verticillium albo-atrum is seed transmitted (CABI, 2021).
Wilt diseases caused by V. albo-atrum are indistinguishable from those caused by V. dahliae, and it is often necessary to isolate the pathogen before the cause can be verified. The two species share several hosts; they also co-exist in cool-temperate regions, where they are often isolated from the same host in the same fields (CABI, 2021).
The Fruit SEWG was uncertain whether plants for planting was a significant pathway.
The natural host range of V. albo-atrum s.l. is narrower than that of Verticillium dahliae. However, under experimental conditions, V. albo-atrum can cause severe symptoms in plants in which it never (or rarely) causes disease naturally (Hou et al., 1995; CABI, 2021).
Compared with the microsclerotia of Verticillium dahliae, the dark, resting mycelium of V. albo-atrum has limited powers of survival and, for herbaceous hosts, loses viability too rapidly for it to be a major inoculum source in proper crop rotation (McKeen & Thorpe, 1973, 1981; Keinath & Millar, 1986); although in woody-host tissues survival may extend up to 4 years (Sewell & Wilson, 1966). The colonization of dicotyledonous weeds, rotation crops and ‘volunteer’ potato plants may contribute to bridging the period between susceptible crops (Heale & Isaac, 1963; Skadow, 1969; Celetti et al., 1990; cited in CABI, 2021). In hop gardens the pathogen can be disseminated in diseased leaves which absciss prematurely, or by cultivation operations which move infected debris. The pathogen can be disseminated with infected planting material e.g. in hops and either within potato seed tubers or as a surface contaminant of the tubers (Beckman et al., 1969; Sampson, 1980; cited in CABI).
V. albo-atrum is almost entirely limited to cool, temperate regions, although it does occur locally on potatoes at high altitude in the tropics (Turkensteen, 1987) and there are reports of a high-temperature strain affecting lucerne in southern California, USA (Howell & Erwin, 1995; Erwin & Howell, 1998). Most of the reports that were used by CMI (1986) are of V. dahliae: that distribution is therefore misleading (CABI, 2021)
Verticillium albo-atrum is seed transmitted (CABI, 2021).
Wilt diseases caused by V. albo-atrum are indistinguishable from those caused by V. dahliae, and it is often necessary to isolate the pathogen before the cause can be verified. The two species share several hosts; they also co-exist in cool-temperate regions, where they are often isolated from the same host in the same fields (CABI, 2021).
The Fruit SEWG was uncertain whether plants for planting was a significant pathway.
5 - Economic impact:
Are there documented reports of any economic impact on the host?
No
Justification:
For pome fruits diseases caused by Verticillium spp. are not mentioned in the crop compendium for disease in pome fruits of the American Phytopathological Society, also Smith et al (1988) indicate that an pome fruits seem to be the exception to susceptibility for Verticillium spp.
[In the responses to the questionnaire, NL and SI supported deregulation in the EU. NL commented that Malus was not an important host. Although Verticillium species can cause dieback, SI considered that infections of Malus are relatively rare.]
[In the responses to the questionnaire, NL and SI supported deregulation in the EU. NL commented that Malus was not an important host. Although Verticillium species can cause dieback, SI considered that infections of Malus are relatively rare.]
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:
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 report of economic impact of V. albo-atrum s.l. alone on this host.
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:
- Beckman CH, Stessel GJ & Howard FL (1969) Verticillium spp. and associated fungi from certified potato seed tubers. Plant Disease Reporter 53, 771-773.
- CABI (2021) Verticillium albo-atrum (verticillium wilt of lucerne). CABI Digital Library (Accessed 30/May/2024). https://doi.org/10.1079/cabicompendium.56268.
- CMI (1986) Distribution Maps of Plant Diseases. Map. No. 365. Wallingford, UK: CAB International..
- Celetti MJ, Johnston HW & Platt HW (1990) A note on the incidence of soilborne fungi in six crops used in rotation with potatoes. Phytoprotection 71(2), 97-100.
- Erwin DC & Howell AB (1998) Verticillium survives heat in Mojave Desert alfalfa. California Agriculture 52(4), 24-27.
- 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 Verticillium dahlia Kleb.
- Howell AB & Erwin DC (1995) Characterization and persistence of Verticillium albo-atrum isolated from alfalfa growing in high temperature regions of southern California. Plant Pathology 44(4), 734-748.
- Hou TJ, Huang HC & Fraser J (1995) Pathogenicity of Verticillium albo-atrum and V. dahliae on fifteen species of forage legumes. Acta Phytopathologica Sinica 25, 189-192.
- Keinath AP & Millar RL (1986) Persistence of an alfalfa strain of Verticillium albo-atrum in soil. Phytopathology 76(6), 576-581.
- Koike ST (1988) First report of Verticillium wilt (V. albo-atrum) of Vinca major in California. Plant Disease 72, 1077.
- McKeen CD & Thorpe HJ (1973) Pathogenic species of Verticillium in horticultural crops and weeds in southwestern Ontario. Canadian Journal of Plant Science 53(3), 615-622.
- McKeen CD & Thorpe HJ (1981) Verticillium wilt of potato in southwestern Ontario and survival of Verticillium albo-atrum and V. dahliae in field soil. Canadian Journal of Plant Pathology 3(1), 40-46.
- Sewell GWF & Wilson JF (1966) Verticillium wilt of the hop: the survival of V. albo-atrum in soil. Annals of Applied Biology 58, 241-249.
- Heale JB & Isaac I (1963) Wilt of lucerne caused by species of Verticillium. IV. Pathogenicity of V. albo-atrum and V. dahliae to lucerne and other crops; spread and survival of V. albo-atrum in soil and in weeds; effect upon lucerne production. Annals of Applied Biology 52, 439-451.
- Sampson PJ (1980) Infection of Kennebec potato with Verticillium albo-atrum. Australian Journal of Agricultural Research 31(3), 525-532.
- Smith IM, Dunez J, Phillips DH, Lelliot RA & Archer SA (eds) (1988) European handbook of diseases: Verticillium dahlia Kleb. and Verticillium albo-atrum Reinke & Berthold. Blackwell Scientific Publications Oxford, UK. 299-302.
- Skadow K (1969) Untersuchungen uber die Welkeerreger Verticillium albo-atrum Rke. et Berth. und V.dahliae Kleb. Zentralblatt fur Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene 123, 715-735