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 pox of stone fruit by causing acidity and deformities. The only way to manage the disease is to destroy all infected trees, which can cause significant economic losses. The disease symptoms were first seen in Bulgaria around 1916-1917, thus the name of "sharka" - from Bulgarian "шарка", meaning "pox". In 1933, the virus origin was described by Dimitar Atanasov. The disease developed in several European countries. The plum pox virus is a linear single stranded RNA virus. There are nine strains of plum pox virus: PPV-D, PPV-M, PPV-EA, PPV-C, PPV-Rec (Recombinant), PPV-W, PPV-T, PPV-CR, and PPV-An. PPV-M isolates are more aggressive