Introduced Pests Outreach Project
PEST ALERT: Plum Pox Virus Detected in New York and Michigan (August 2006)

Pest Alert: Plum Pox Virus Detected in New York and Michigan (August 2006)

On July 17 the USDA National Plant Germplasm and Biotechnology Laboratory in Beltsville, MD confirmed the presence of the plum pox virus (PPV) on plum leaf samples collected by New York State Department of Agriculture and Markets from Niagara County, New York on July 17. The leaf samples were collected as part of a seven-year survey for the virus by state and federal officials. On August 11 the Beltsville lab confirmed a plum tree at the Southwest Michigan Research and Extension Station was infected with the plum pox virus. The Michigan Department of Agriculture has participated in the national plum pox survey since 2000 and will continue to sample PPV hosts within 5 miles of the PPV infected tree.

Plum pox virus, also known as sharka, was first reported from Bulgaria in 1915. PPV has spread throughout much of Europe and has also been reported from the Middle East, North Africa, India, and Chile. The virus infects Prunus species including peaches, nectarines, apricots, plums, almonds, and some ornamental Prunus cultivars. PPV does not pose any human health risks. It is unknown how the plum pox virus was brought to the United States. The virus can be carried long distances in infected nursery stock or propagative materials and can be transmitted between plants by aphid feeding.

Plum pox virus was first detected in North America in October of 1999 in Adams County, Pennsylvania. In 2000 the virus was detected in Nova Scotia and Ontario, Canada. The orchard that tested positive for PPV in New York was within 5 miles of the plum pox eradication zone in Ontario. The United States and Canada have eradication programs in place for PPV that include establishment of quarantine areas, destruction of infected trees and nearby host material, and an intensive survey program to detect further PPV infection. The only strain of PPV to be found in North America is the D strain, a less virulent strain of PPV that is not know to affect cherry trees. The D strain is also not transmitted by seed; therefore, the presence of PPV will not affect the harvest and transportation of stone fruit in NY or MI.

Plum pox is economically important because the symptoms of the virus can render the fruit unmarketable and infected trees have lower yields. Infected fruit can develop yellow rings or blotches. Some plum and apricot fruits can be severely deformed and bumpy. Symptoms on the leaves include chlorotic or yellow lines or rings, yellowing along the veins and distorted leaves. Symptoms vary depending on the host plant, cultivar, viral strain, age of the host plant, and environmental conditions. The following resources include more information on the plum pox virus and photos of symptoms.

Resources for information on plum pox virus:
Plum Pox Virus- Penn State College of Agricultural Sciences and Cooperative Extension

USDA, APHIS Plum Pox website

Sharka (Plum Pox Virus) Of Stone Fruit And Ornamental Prunus Species- Ontario Ministry of Agriculture and Food

Links to information on latest PPV finds:
New York

This pest alert is from the Massachusetts Introduced Pests Outreach Project, a collaborative project between the Massachusetts Department of Agricultural Resources and the UMass Extension Agriculture and Landscape Program aimed at preventing the establishment of new pathogens and pests in Massachusetts. Visit the project website ( for more information on other emerging pests and to subscribe or unsubscribe from our pest alert list.

Massachusetts Department of Agricultural Resources
Massachusetts Introduced Pests Outreach Project is a collaboration between the Massachusetts Dept. of Agricultural Resources and the UMass Extension Agriculture and Landscape Program. This website was made possible, in part, by a Cooperative Agreement from the United States Department of Agriculture's Animal and Plant Health Inspection Service (APHIS). It may not necessarily express APHIS' views.