The Plum Pox Virus affects a variety of stone fruit species including peaches, apricots, plums, nectarines, almonds, and sweet and tart cherries. Wild and ornamental species of Prunus may also become infected by some strains of the virus. The symptoms of the virus vary with timing of infection, cultivar, species, and environment.
Newly infected trees are rarely symptomatic and visually symptoms are often not apparent until 3 or more years after infection. IT IS CRITICAL THAT SYMPTOMLESS TREES BE REGARDED SERIOUSLY AS THEY WILL ACT AS A SILENT VIRUS SOURCE.
Visual symptoms may appear on leaves, fruit, flowers, and the stone (seed). The leaves have yellow or light green patterns, bands, or blothes on them. The fruit may have similar symptoms. The symptoms occur sporadically (uneven distribution within the tree). This is why when sampling a collection of leaves is taken from various areas all over the tree.