page_title: Plum pox
section_title: Pathology
hierarchical_section_title: Plum pox / Pathology
caption_attribution_description: An alate (winged) green peach aphid (Myzus persicae), an important vector of plum pox virus.
context_page_description: Plum pox, also known as sharka, is the most devastating viral disease of stone fruit from the genus Prunus. The disease is caused by the plum pox virus, and the different strains may infect a variety of stone fruit species including peaches, apricots, plums, nectarine, almonds, and sweet and tart cherries. Wild and ornamental species of Prunus may also become infected by some strains of the virus.
  The virus is transmitted by aphids and by the transfer of infected plant material to new locations. Plum pox poses no danger to consumers, but it can ruin the marketability 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.
context_section_description: Several species of aphid transmit the virus including the plum-thistle aphid (Brachycaudus cardui), the plum leaf curl aphid (Brachycaudus helichrysi) and the green peach aphid (Myzus persicae). Winged aphids can transmit plum pox within an orchard, and over short distances (200–300 meters) to trees in nearby orchards. Unlike some other viruses, like barley yellow dwarf virus, PPV is not persistent in the aphid and is transferred from the mouthparts of the aphid between plants. Long distance spread usually occurs as a result of the movement of infected nursery stock or propagative materials. Once a plant is infected the virus is systemic and occurs in the cytoplasm of cells from all parts of the plant.
  When a host tree is infected by plum pox, the infection eventually results in severely reduced fruit production, and the fruit that is produced is often misshapen and blemished. The presence of plum pox can also enhance the effects of other endemic viruses infecting various species of the genus Prunus, such as prune dwarf virus, Prunus necrotic (browning) ringspot virus, and apple chlorotic (yellowing) leaf spot virus, resulting in still greater economic losses.
  In peach, infected trees may exhibit color-breaking symptoms in the blossoms. This appears as darker pink stripes on the flower petals and can be useful for early season surveys. Symptoms can be present in young leaves in the spring and /or on developing fruit. Some trees 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 some cases found naturally infected in the field. The maintenance of the virus in non-Prunus species complicates disease management.
caption: The aphid Myzus persicae is a vector for plum pox virus in the United States.
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