The Plant Health and Nursery & Christmas Tree programs, in cooperation with officials from the USDA APHIS Plant Protection and Quarantine Program (USDA APHIS-PPQ), administer the Phytophthora ramorum Certification Program for the state of Oregon. All nurseries that have been found positive for P. ramorum since March 2011 and ship regulated host plant material out of state must participate. These nurseries are subject to biannual surveys where inspectors sample suspect host material, water, and soil. Nurseries that ship regulated host plant material within state are subject to similar regulatory procedures, however this is overseen by ODA only.
Along with USDA APHIS-PPQ, ODA also oversees regulatory matters of the Sudden Oak Death quarantine area of Curry Country, Oregon. The Oregon Department of Forestry and US Forest Service direct disease mitigation efforts within the infested areas in southwestern Oregon.
What is Sudden Oak Death?
Sudden Oak Death (SOD) is a disease caused by the invasive fungal-like pathogen, Phytophthora ramorum
. Since its first detection in northern California in the mid 1990s, P. ramorum
has been found to naturally infect over 100 different plant species.
The USDA APHIS-PPQ maintains the official regulated host list
Different hosts, different symptoms
Depending on the host in question, infection can result in one of two diseases: Sudden Oak Death (SOD) or Ramorum shoot dieback and leaf blight. Each of these diseases causes a variety of symptoms that can vary in severity.
SOD causes the rapid dieback of members of the Oak family (Fagaceae),
most notably tanoak and coast live oak. It is characterized by
bleeding cankers that girdle the trunks of the trees, causing death.
This 'sudden' death appears to happen very quickly, although the tree
may actually have been infected for several months.
Ramorum shoot dieback and leaf blight are diseases associated with multiple plant species, many of which are commonly sold in ornamental nurseries. This infection typically does not fully kill a plant. However, the dieback on some highly susceptible cultivars and species may become severe enough to kill the plant. Within ornamental nurseries, the following five genera of plants are most frequently found infected with P. ramorum: Rhododendron, Camellia, Viburnum, Pieris, and Kalmia. The symptoms on rhododendron are virtually identical to those caused by other aerial Phytophthora species. This is why laboratory testing is crucial for accurate diagnosis.
For additional information, detailed descriptions, and images
of symptoms refer to Sudden Oak Death (OSU Cooperative Extension)
Where is Sudden Oak Death found in Oregon?
Phytophthora ramorum is present in a number of Oregon nurseries. The wildlands surrounding the city of Brookings in Curry Country is the only region of the state where the pathogen is found in natural settings. It is believed that the pathogen was introduced into the area through infected nursery plants. Curry country is under a partial quarantine and growers of host plant material are subject to quarantine restrictions for movement.