Symptoms of the virus highly vary and depend on several factors including the host, environmental conditions. In most cultivars, the viral infection remains symptomless. Some varieties will show a slight deepening of the veins, rough leaves, more open growth, milt mottling, bronzing or tiny necrotic (black) spots on the leaves when infected at an early growth stage.
The damage is caused by the Potato S Virus, which is a Carlavirus. It is mainly transmitted in a non-persistant manner by aphids. It can also be spread mechanically by machinery, tools and damaging plants while walking through the field. Aphids are by far the most efficient means of transmission. Plants tend to be resistant to PVS later in the season.
Predators of aphids are numerous and should be promoted through good field practices. Aphids can also be wiped out by spraying the leaves of the plant with a mild solution of water and a few drops of detergent.
Always consider an integrated approach with preventive measures together with biological treatments, if available. Although the virus cannot be treated directly by chemicals, the vector of transmission, mainly aphids, can be controlled up to a certain point. Check the database for aphids and their possible chemical control. Label claim insecticides for aphids are given in our product sheet.