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Justification for qualification based on EPPO PM 4 Standards
Justification for disqualification
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NAME OF THE ORGANISM: Verticillium dahliae (VERTDA)

GENERAL INFORMATION ON THE PEST

Name as submitted in the project specification (if different):

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):

2 – Status in the EU:

Is this pest already a quarantine pest for the whole EU?

Presence in the EU:

Yes

List of countries (EPPO Global Database):

Austria (2014); Belgium (2015); Bulgaria (1986); Croatia (2016); Cyprus (2011); Czech Republic (2011); Denmark (1986); France (1986); Germany (2012); Greece (2013); Greece/Kriti (2013); Hungary (1986); Italy (2007); Malta (2007); Netherlands (2018); Portugal (1986); Slovakia (2012); Slovenia (2017); Spain (2021)

Conclusion:

Justification (if necessary):

Data of the presence of this pest on the EU territory are available in EPPO Global Database (https://gd.eppo.int/). V. dahliae is present in most EU Member States (MSs), with the exception of Ireland (absent, no pest records) and Poland (absent/uncertain). The current status of V. dahliae in the MSs where the pathogen is known to occur ranges from “restricted distribution” to “widespread” (EFSA, 2014).

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

3 - Is the pest already listed in a PM4 standard on the concerned host plant?

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:

Candidate by default

Justification:

Verticillium dahliae is a soil-borne fungus that causes Verticillium wilt diseases in an extremely wide host range of annual and perennial dicotyledonous plant. Its primary economic hosts include: artichoke, aubergine, bell pepper, cotton, hop, lettuce, mints (Mentha spp.), oilseed rape, olive, potato, strawberry and tomato (CABI, 2021); citrus and pome fruits, however, are the exception (Smith et al. 1988).
Verticillium dahliae can survive for 14 years in soil as microsclerotia (form of resting spores) (Wilhelm, 1955), either free or embedded in plant debris, which are stimulated to germinate in response to root exudates (Mol, 1995). Infection of plants, both individuals and populations, is directly related to the inoculum density of microsclerotia in the soil (Pullman & DeVay, 1982; Harris & Yang, 1996; Mol et al., 1996; Xiao & Subbarao, 1998).
Verticillium dahliae is seed transmitted (CABI, 2021)
Verticillium dahliae can easily be dispersed by propagation material (nursery stock) of both herbaceous and woody hosts (e.g. Keykhasaber et al., 2018).

5 - Economic impact:

Are there documented reports of any economic impact on the host?

Justification:

Disease symptoms may comprise wilting, chlorosis, stunting, necrosis and vein clearing. Brown vascular discoloration may be observed in stem tissue cross-sections (Frandin & Thomma, 2006). Symptoms of Verticillium wilt diseases can vary between hosts; thus, there are no unique symptoms that develop on all plants infected by V. dahliae (Fradin and Thomma, 2006). Moreover, symptoms can vary depending upon strains (pathotypes) of the pathogen (Korolev et al., 2008; Jiménez-Díaz et al., 2012).
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 (Sutton et al., 2014), also Smith et al (1988) indicate that an pome fruits seem to be the exception to susceptibility for Verticillium spp.
When testing the reaction of five apple cultivars to infection with V. dahliae, Karajeh & Owais (2012) has shown that only one cultivar (cv. Delicious Anbari) produced typical wilt symptoms (with only 8% disease severity), whereas scions of the other four apple cultivars (Royal Gala, Double Red, Golden Delicious, and Granny Smith) did not show any symptoms. By contrast, inoculation of an olive cultivar (Nabali Mohassan) caused typical symptoms with 61% severity.
[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?

Conclusion:

Not candidate

Justification:

Remark: no reason to consider possible unacceptable economic impact to other hosts with this species more than with another species which is not regulated at present.

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 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:

CABI (2020) Verticillium dahliae (verticillium wilt), CABI Digital Library (Accessed 30/May/2024).
EFSA (2014) Scientific opinion on the pest categorisation of Verticillium dahliae Kleb.1. EFSA Panel on Plant Health (PLH). EFSA Journal 12(12), 3928, 54 pp.
Fradin EF & Thomma BP (2006). Physiology and molecular aspects of Verticillium wilt diseases caused by V. dahliae and V. albo-atrum. Molecular Plant Pathology 7(2), 71-86. doi: 10.1111/j.1364-3703.2006.00323.x.
Harris DC & Yang JR (1996). The relationship between the amount of Verticillium dahliae in soil and the incidence of strawberry wilt as a basis for disease risk prediction. Plant Pathology 45(1), 106-114.
Jiménez-Díaz RM, Cirulli M, Bubici G, Jiménez-Gasco MM, Antoniou PP & Tjamos EC (2012). Verticillium wilt: a major threat to olive production. Current status and future prospects for its management. Plant Disease 96, 304–329.
Karajeh MR & Owais SJ (2012) Reaction of selected apple cultivars to wilt pathogen Verticillium dahlia. Plant Protection Science 48, 99–104.
Keykhasaber M., Thomma BPHJ & Hiemstra JA (2018) Verticillium wilt caused by Verticillium dahliae in woody plants with emphasis on olive and shade trees. European Journal of Plant Pathology 150, 21-37.
Korolev N, Pérez-Artés E, Mercado-Blanco J, Bejarano-Alcázar J, Rodríguez-Jurado D, Jiménez-Díaz RM &, Katan T & Katan J (2008) Vegetative compatibility of cotton-defoliating Verticillium dahliae in Israel and its pathogenicity to various crop plants. European Journal of Plant Pathology 122, 603–617. DOI 10.1007/s10658-008-9330-1
Mol L, Halteren JM van, Scholte K & Struik PC (1996). Effects of crop species, crop cultivars and isolates of Verticillium dahliae on the population of microsclerotia in the soil, and consequences for crop yield. Plant Pathology 45(2), 205-214.
Pullman GS & DeVay JE (1982). Epidemiology of Verticillium wilt of cotton: a relationship between inoculum density and disease progression. Phytopathology 72(5), 549-554.
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.
Sutton TB, Aldwinckle HS, Agnello AM & Walgenbach JF (2014). Compendium of Apple and Pear Diseases and Pests 2nd edition. American Phytopathological Society, St Paul, MN, USA
Wilhelm S (1955) Longevity of Verticillium wilt fungus in the laboratory and the field. Phytopathology 45, 180-181.
Xiao CL & Subbarao KV (1998). Relationships between Verticillium dahliae inoculum density and wilt incidence, severity, and growth of cauliflower. Phytopathology 88(10), 1108-1115