Potato leafroll virus

Potato leafroll virus manifests through characteristic deformation of leaf blades. In secondary infection transmitted via infected tubers, the lower leaves roll into a 'tube', become stiff and leathery, sometimes acquiring a reddish-purple hue. Primary infection acquired during the current season affects young upper leaves, which point upwards and have a pale green hue; meanwhile, net necrosis of the flesh is frequently recorded in the tubers.

The spread of the disease depends on the activity of vectors, in particular the green peach aphid, as well as weather conditions. Dry and hot weather contributes to more intense visual manifestation of symptoms. The virus persists in infected seed material, which leads to progressive variety degradation and a decrease in crop quality, including a drop in starch content and tuber marketability.

The assessment of variety resistance during variety testing is based on a combination of visual field recording of infected plants and laboratory diagnostic methods, such as ELISA and PCR, which allow for the detection of latent infection. Breeding is aimed at developing field resistance, which limits pathogen accumulation in plant tissues or reduces their attractiveness to insect vectors.