Causal agent(s) and transmission
Potato virus V (PVV) was first described in 1986 and grouped together several particular isolates previously thought to be PVY isolates. Field research carried out in France in 1991, revealed the presence of PVV in several cultivars (Rosa, Spunta, Bintje, Claustar, Sirtema, etc.).
PVV is fairly common in the UK and has also been reported in Peru, Germany and the Netherlands.
Most potato cultivars react hypersensitively to inoculation, developing local necrotic lesions and severe systemic necrosis. They are rarely found infected in the field.
Whilst the Irish strain of the virus naturally induces tuber necrosis in a number of British cultivars, PVV is usually associated with latent infections or mild mosaic symptoms, some decrease in leaflet size and slight leaflet distortion. However, some susceptible cultivars develop mosaic pattern and necrotic spotting of lower leaves. When examined visually, it is usually confused with other potyviruses, such as PVA or PVY, which can give false negatives when these viruses are Elisa tested.
PVV detection kits are commercially available and the virus can be detected by the Elisa test.
PVV is transmitted in a non-persistent manner by aphids (Myzus persicae, Brachycaudus helichrysi, Macrosiphum euphorbiae, Rhopalosiphoninus latysiphon...).