Main symptoms

The alfalfa mosaic virus ( Alfalfa mosaic virus , AMV) produces bright white or yellow spots of varying size, usually angular and located along the veins. We can sometimes observe small whitish rings. Often, these alterations affect only one to two leaves of the skirt. More rarely, some leaves can present a real mosaic with light yellow areas (figures 1 to 4).

In the United States, where this virus has received the name "calico", affected plants are sometimes stunted and show leaf necrosis.