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
Links to information on latest PPV finds:
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
for more information on other
emerging pests and to
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