Plum pox show no symptoms on leaves or fruit. Not all infection in "Prunus" are characterized by a ring symptom on leaves. Several cultivars show yellowing line patterns and blotches, or necrotic ring symptoms on expanded leaves. Leaf distortion has also been observed. Infected fruit can develop yellow rings or blotches, or brown rings, and some plum and apricot fruit can be severely deformed and bumpy. The seed of many infected apricots and some plums show rings. Many non-"Prunus" species, in at least nine plant families, have been infected artificially with one or more strains of the plum pox virus, and in
Plum (color) Plum (color) Plum is a purple color with a brownish-gray tinge, like that shown on the right, which is a close representation of the average color of the plum fruit. As a quaternary color on the RYB color wheel, plum is an equal mix of the tertiary colors russet and slate. The first recorded use of "plum" as a color name in English was in 1805. At right is displayed the color pale plum, which is the pale tone of plum that is the web color called "plum". This color is paler than the color at the head of this