The strain reported in the United States does not affect cherries. Symptoms Plum pox symptoms can vary greatly, making the disease difficult to recognize. Symptoms may appear on the leaves or fruits of infected trees. In some cases, only part of the infected tree or even only a single branch will show symptoms. Symptoms are easiest to see in the spring when leaves show chlorotic spots, bands, or rings, vein clearing and even leaf deformation.
Infected fruits show chlorotic spots or rings.
Diseased plums and apricots may be deformed with internal browning of the flesh and pale rings or spots on the stones. Visual symptoms are not always a reliable indicator of disease. The disease may not be visible until several months or years after the tree has been infected. However, PPV can also be detected by laboratory analysis of tissue samples or by grafting test material to highly susceptible hosts and watching for symptoms to develop. The main source of plum pox is infected trees or budwood.