August 11, 2006, Lansing, MI - The Michigan Department of Agriculture and Michigan State University today announced that aggressive efforts are underway to manage the presence of a viral plant disease known to infect certain stone fruits, such as peaches, nectarines, apricots, and plums. The strain identified, however, is not known to affect cherry trees. The United States Department of Agriculture earlier confirmed plum pox virus (PPV) in samples collected from a routine survey at the MSU Southwest Michigan Research and Extension Center (SWMREC), near Benton Harbor. PPV poses no human or animal health threat.

"Michigan and its partners have always worked closely to protect the state's agricultural diversity," said Robin Rosenbaum, MDA Plant Industry Section Manager. "Early discovery of the virus through routine surveillance demonstrates that this aggressive approach to plant pests and diseases works."

The USDA will establish a cooperative eradication program with the state of Michigan, including extensive detection and delimiting surveys, establishing a quarantine if needed in areas where infections are found, and removing infected orchards and other host material within the buffer area of any infection. MDA specialists are currently surveying blocks of trees in the immediate vicinity of the infected tree to determine the extent of infection.

"We know there is no risk to nonsusceptible crops, and we are collaborating with the agencies to analyze the leaf samples that are collected," says Ray Hammerschmidt, MSU Department of Plant Pathology chairperson and coordinator of MSU Diagnostic Services. "Hopefully, this will be an isolated situation."

The D strain identified in Michigan is the same strain discovered in Pennsylvania in 1999, and later Canada and New York. It is less virulent than other strains, not as easily transmissible by aphids, and will not affect the production, harvest or transportation of stone fruit in Berrien County this year since this strain is not transmitted by fruit.

PPV can be transmitted by aphids or transplanted rootstock, however, it is too early to determine the source of the virus in the Michigan tree. USDA and MDA personnel are working to establish both the extent and the origination of the SWMREC incidence. PPV has not been found in any other Michigan location.

Area growers are invited to attend a public information session on Wednesday, August 16, 2006, at 6:30 p.m. at MSU Southwest Michigan Research and Extension Center, 1791 Hillandale Road, Benton Harbor, MI 49022.

To learn more about plum pox virus, visit the USDA Animal and Plant Health Inspection Service Web page.

A fact sheet on plum pox can also be found here.