Plum Pox (PPV)/Sharka Potyvirus

The Plum Pox Virus is the most devastating viral disease of stone fruit. Different strains may infect a variety of stone fruit from the Prunus family including peache, 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 virus reduces fruit yields and the marketability of fruit. The fruit trees are rendered useless for fruit tree production and shortens the productive lifespan of orchards.

PLUM POX VIRUS IS NOT DANGEROUS TO HUMANS

Overall Quarantine and Regulated Areas for Western New York

Long distance spread of PPV is the result of moving infected nursery stock or propagative material to a new region. Grafts and budwood are also ways of moving infected material..

Secondary transmission, or short distance spread, is by aphids. Spread of the virus by aphids can be rapid and is highest in the spring and autumn. This occurs within an orchard and to trees in nearby orchards. The virus is transferred from the mouthparts of the aphid between plants. The aphid probes the leaves with its sap-sucking mouth part called the stylet. The stylet penetrates the leaf tissue and draws up cell content. Virus particles are pulled into the stylet and sticks to the lining of the food canal. The virus can be sustained in the food canal for up to an hour. The aphid flies to another tree and probes the next leaf where the virus is transferred to a healthy tree when the aphid expels the stylus contents during the probe. The virus is non-persistent in the aphid, meaning that the virus does not replicate nor does the virus enter the circulatory system of the aphid.

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.

Following the discovery of PPV in New York, the U.S. Secretary of Agriculture declared an extraordinary emergency to effectively carry out an eradication program in the state.

No chemical control is available to prevent, eliminate, or cure PPV. Control of PPV spread is accomplished by eliminating infected trees as quickly as possible. Exclusion, quarantine, and restriction protects growers! Infected trees must be removed and destroyed as soon as possible (50 meter radius around positive) including any sucker shoots.The only way to manage the disease is to destroy all infected trees which can cause significant economic loss.

The statewide survey of Prunus trees for PPV is a critical component of an eradication program aimed at eliminating the virus in New York.

Mafalda Weldon
National Director Plum Pox Virus Eradication Program
USDA-APHIS-PPQ
Telephone: (717) 241-0705
Toll-Free: (800) 249-2363
E-Mail: Mafalda.Weldon@aphis.usda.gov

Contact

Patricia Sierzenga
Plum Pox Virus Eradication Program
Horticultural Inspector 2
NYSDAM - Plant Industry
PO Box 64952
Rochester, New York 14624
Telephone (Office): (585) 889-9715
Telephone (Cell): (585) 370-1606
E-Mail: patricia.sierzenga@agriculture.ny.gov

Links

Cornell University - New York State Agricultural Experiment Station, Geneva, NY

USDA Animal and Plant Health Inspection Service - Plant Health - Plum Pox Virus

Federal Regulations

Federal Orders

ELISA Sample Processing