PVY

Symptoms: Primary infection

• Necrotic or chlorotic circles on infected leaves followed by deep veins
• Top leaves develop green to light yellow spots
• Symptoms are usually not visible until the end of the season

Symptoms: Secondary infection

• All leaves show chlorotic symptoms
• Necrotic spots and dots on the leaf, mosaic-like symptoms and necrosis of petiole and stem
• Symptom expression varies widely between varieties

Infection and spread

• Mainly by peach-potato aphid (Myzus persicae), but also Aphis nasturtii, Macrosiphum euphoribae, Brachycaudus helichrysi and Sitobion avenae
• Seed tubers
• A non-persistent virus
• PVY variants YN, YNTN, Y^O, Y^C