european and mediterranean plant protection organization
00/8487
PPM Point 8.5
Draft Data Sheets
Potato rough dwarf ?carlavirus
Identity
Name: Potato rough dwarf ?carlavirus
Taxonomic position: Viruses: ?Carlavirus
Common names: PRDV (acronym)
EPPO computer code: -
EPPO A1 list: -
EU Annex designation: -
Hosts
PRDV has been detected in potato (Solanum tuberosum). The experimental range is narrow, equivalent to that of PVSo but with additional hosts and hosts with different symptoms.
Geographical distribution
EPPO region: Absent.
South America: Argentina. Limited to Balcarce region of Buenos Aires province. Also found in Solanum tuberosum cv. Red Pontiac received from Uruguay.
EU: Absent.
Biology
PRDV seems identical serologically to potato virus P (PVP) described from Brazil since PVP antiserum detects PRDV. However, reactions in indicator plants appear to differ: PRDV does not infect Lycopersicon esculentum and PVP does not infect Chenopodium spp. PRDV is serologically distinct from potato virus S ordinary strain and potato latent virus (PotLV). Work is under way to determine the relationship between PRDV and PVP and the other carlaviruses affecting potato, potato virus M, PotLV and PVS. It has not been specifically reported that PRDV is present in, or transmitted by, tubers, but the description of its economic impact in Argentina strongly suggests that it is.
Detection and identification
Symptoms
The cultivars Achat, Jaërla, Kennebec, Primicia and Sierra Volcán show dwarfing of the plant and a thickening of old leaves which become rough. Some cultivars (Americana, Araucana, Atlantic, Granola, Huinkul and Spunta) show no symptoms. Ballenera and Bintje show moderate symptoms.
Morphology
The virus has slightly flexuous filamentous particles 638 nm long.
Detection and inspection methods
Indicator plants
Sap inoculation of most indicator plants is unreliable with the possible exception of clone "A6" (S. demissum x S. tuberosum cv. Aquila) (local conspicuous chlorotic lesions on detached leaves), and Chenopodium quinoa (inoculate well-grown plants, systemic chlorotic spots after 40 days).
Serological detection methods
PRDV can be detected by ELISA.
Molecular detection methods
PRDV is reliably detected by PCR using carlavirus-specific primers such as those described by Badge et al. (1996), but the homologous antibody must then be used to identify PRDV specifically.
Means of movement and dispersal
In international trade, PRDV could be transmitted by potato plants or tubers.
Pest significance
Economic impact
PRDV is of little importance locally. Its incidence is 4% and 0.4% in Spunta and Kennebec, the two most important cultivars grown in Argentina. The cultivar Sierra Volcán, which is only grown in the breeding collection at Balcarce experimental station may be 60% infected. All nuclear stock in vitro material and basic seed potatoes are routinely tested. PRDV has not been found infecting certified material.
Control
As with all potato viruses, control depends on the production of high-quality seed potatoes from virus-free nuclear stock.
Phytosanitary risk
Potato is an important crop for the EPPO region, for which certification schemes are implemented. The principal perceived risk is the introduction of new viruses into seed potato production schemes, increasing the cost and difficulty of operating these schemes. It is clear that PRDV would very probably be tuber-transmitted through such a scheme. Any seed potato-exporting country in which PDMV was reported would immediately find itself in difficulties with respect to the phytosanitary certification of its exports. Also, there is a risk of introduction due to the increased international exchanges of breeding material and germplasm. However, PRDV seems to have a low incidence where it occurs.
Phytosanitary measures
Bibliography
Badge J, Brunt A, Carson R, Dagless E, Karamagioli M, Phillips S, Seal S, Turner R & Foster GD (1996) A carlavirus-specific PCR primer and partial nucleotide sequence provides further evidence for the recognition of cowpea mild mottle virus as a whitefly-transmitted carlavirus. European Journal of Plant Pathology, 102, 305-310.
Butzonitch IP, Nieto A, Truol GAM, Colavita ML (1995) p. 39 In: Caracteristicas de un nuevo carlavirus relacionado con el virus S de la papa hallado en Balcarce, Argentina. V Congreso Argentino de Virologia. Il Encuentro de virologos Latinoamericanos, 24-27 April 1996, Tandil, Buenos Aires.
Calderoni AV (1978) Posibles virosis no identificadas. Pp 77-78 in Enfermedades de la Papa y su Control. Buenos Aires, Hemiserio Sur.
Jeffries CJ (1998) FAO/IPGRI Guidelines for the Safe Movement of Germplasm No. 19: Potato. FAO/IPGRI, Rome.
Martin J & Kerlan C. (1998) Comparative study of different carlaviruses infecting potato. Pp 65-66 in Abstracts of the 10th EAPR Virology Section Meeting, 5-10 July 1998, Baden, Germany.