Potato virus Y – PVY

Kind of organism : Virus

Detection method : ELISA

All diseases & pests

Causal agent(s) and transmission

Potato virus Y (PVY, type-member of the genus Potyvirus) is one of the most economically serious plant viruses. It is currently recognised as the most damaging potato virus in the world for seed and processed potatoes. PVY is transmitted by at least 70 aphid species in a non-persistent manner. Acquisition and inoculation periods are short (around one minute) and retention of the virus in the aphid vector usually lasts no more than 1 to 2 hours. PVY can infect a very wide range of cultivated and weed plant species, belonging mainly to the family Solanaceae (tomato, tobacco, pepper, etc.).

The sources of PVY inoculum resulting in the infection of potato crops are usually infected seed tubers or volunteers within the field but virus reservoirs may also be present in neighbouring fields, gardens or the adjacent environment, either on infected potatoes or on other host plants (tomato, tobacco, weeds such as nightshades).

PVY can cause yield reduction up to 50%, and even 80% on susceptible cultivars or in the case of co-infection with other viruses.

Symptoms on foliage

Symptoms caused by PVY vary widely with the combination of the virus strain, the potato cultivar, the environmental conditions and the type of infection (either primary i.e. current- season infection, or secondary i.e tuber-borne infection).

Field infection during the current-season with PVYisolates (primary infection) results in symptoms of vein necrosis and necrotic spots on the underside of the leaflets (photo 1). The leaves become brittle and dry, but remain attached to the plant (so-called leaf-drop symptom). Primary infection can also produce a distorting mosaic symptom and crinkling, often confined to one stem or one part of the plant.

Secondary infection, i.e. infection resulting from tubers contaminated from the previous year, produces more severe symptoms, which vary widely with the infected cultivar. One of the three following types can usually be observed:


PVYN isolates cause faint mosaic patterns in plants infected during the current season, while infection in the previous year (infected mother-tubers) gives more or less marked or mild mosaic symptoms.

PVYN-W isolates induce faint mild mosaic symptoms (mainly in the case of primary infection) with some vein deepening (photo 12).

Risk factors

The development of PVY infection results from the combination of different sources of infection, either internal (volunteers, seed tubers, weeds) or external (nearby potato crops, gardens, weeds such as Solanum dulcamara or Datura spp.), the significance of flights of aphids during the growing season (related to climatic conditions and nearby crops), the level of control measures taken in seed potato production (roguing, crop management such as weed control, crop protection, haulm destruction or field and lot inspection) and finally the level of the susceptibility of the grown potato cultivar.


It is essential to use certified seed potatoes to limit the infection of potato crops by viral diseases, particularly PVY. Production of certified seed potato is formally based on a range of strict measures designed to limit the infection by viral diseases. They include:


Additional control measures in seed potato production taking into account risks of aphid infestations that are usually higher during warm periods, include:

Virus variability

PVY strains are extremely variable and can be classified according to their biological, serological and molecular properties. Three main strains of PVY are usually distinguished:

More recently, new variants of PVY virus have been identified in the PVYN strain group:

The emergence of PVY variants (PVYNTN, PVYN-W) has resulted from genetic recombination events between isolates of the PVYN and PVYO strain groups.

This capacity for genetic recombination allows for the extensive variability of the PVY virus and is associated with an increased risk of new emerging isolates with increased pathogenicity (aggressivity and virulence).