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 content (table). Plum A plum is a fruit of the subgenus "Prunus" of the genus "Prunus." The subgenus is distinguished from other subgenera (peaches, cherries, bird cherries, etc.) in the shoots having terminal bud and solitary side buds (not clustered), the flowers in groups of one to five together on short stems, and the fruit having a groove running down one side and a smooth stone (or "pit"). Mature plum fruit may have a dusty-white waxy coating that gives them a glaucous appearance. This is an epicuticular wax coating and is known as "wax bloom". Dried plum fruits are called