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Sudden Oak Death pathogen potentially in shipment of ornamentals

Posted: September 15, 2014

Phytophthora ramorum, the pathogen involved with Ramorum Blight/Sudden Oak Death was detected at a nursery in Oregon that ships plants to Pennsylvania.
Ramorum blight symptoms on Rhododendron. Photo by Joseph O'Brien, USDA Forest Service, Bugwood.org

Ramorum blight symptoms on Rhododendron. Photo by Joseph O'Brien, USDA Forest Service, Bugwood.org

The Ramorum Blight/Sudden Oak Death pathogen (Phytophthora ramorum) was detected at a nursery in Oregon that had previously shipped plants to nurseries on the east coast, including some in Pennsylvania. As a precaution, The Pennsylvania Department of Agriculture (PDA) is conducting a trace forward to find and test plants shipped to the Commonwealth. It is possible that some of these plants have already been sold. Currently, no plants in Pennsylvania have tested positive for P. ramorum. This disease is not established in Pennsylvania. 

Plants of concern include rhododendron, azalea, pieris and camellia, but the pathogen has a wide host range. There are other Phytophthora species that are commonly found in Pennsylvania that cause Phytophthora root rot and top dieback on rhododendron and azalea and do not cause Sudden Oak Death on oaks. The symptoms for these diseases are the same so an accurate diagnosis is important. Commercial growers and nursery owners should contact their PDA inspector to submit samples for evaluation.

Homeowner samples can be submitted to the Penn State Plant Disease Clinic through your local county extension office. For links to more information on this disease you can visit Extension’s Sudden Oak Death page.