Leaf roll virus infection is characterized by upward rolling of lesf margin so that the undersurface is exposed. When the leafroll virus is carries by seed tuber then leaf rolling is first evident on lower leaves (secondary symptoms).
On recent infected plants rolling usually begins on the upper leaves (primary symptoms). Leaf rolling also results from causes other viruses.

Management and control of potato leaf roll virus

Since the spread of leaf roll virus takes more time than leaf roll virus, insecticide application can be effective if the aphid populations are closely monitored. Colonizing aphids are the most important vectors for this virus because transmission requires an extended feeding period. The green peach aphid, Myzus persicae, is one of the most important vectors. The use of clean seed is critically important. Roguing of infected plants helps prevent the spread of leaf roll virus and early harvest can help prevent late-season infection.

Handling plants will not spread the virus, since leaf roll virus is not mechanically transmissible.