Plum pox is a viral disease of stone fruits first reported in Bulgarian plums in the 1910’s.  More widely known around the world by its Slavic name, sharka, the disease first spread slowly through eastern Europe, gaining momentum in the 1950’s through the 1970’s as it reached western Europe.  Movement of the disease continued in North Africa, the middle East, India and the People’s Republic of China.  The disease was detected in the western hemisphere in Chile in 1992.  In Canada, it was found in Ontario and Nova Scotia in 2000.  In the US, the disease was recorded in Pennsylvania in 1999, followed by New York and Michigan in 2006.

In New York, PPV was identified on two plum trees in July of 2006, followed by a peach tree in August of 2006 in Niagara County.  In August and September of 2007, the virus was found in five peach orchards in Niagara and Orleans Counties.

Plum pox virus (PPV) is the causal agent of plum pox disease. PPV can infect all cultivated stone fruit species including plum, peach, nectarine, apricot, almond, and cherry, as well as wild and ornamental Prunus.

To date, six strains of PPV (D, M, El-Amar, C, W and Rec) have been identified worldwide based on their biological, serological and molecular properties; all occurrences in New York thus far have been identified as strain D.  This strain naturally infects peach, nectarine, apricot and plum; almond and cherry are not natural hosts although they can be artificially infected.  Epidemics of PPV-D progress slowly in peach and this virus strain is not seed-transmitted.

PPV spreads via aphid vectors and through infected plant propagation materials, including nursery stocks or buds collected from infected trees.  New York infections are believed to result from aphid transfer of the virus from Ontario, Canada.