Sudden Oak Death now North of Curry Co. Quarantine Area, April 29

ODF release – SALEM, Ore. – The Oregon Department of Forestry and USDA Forest Service have begun work that will allow treatment in May in Curry County of a newly detected infestation of sudden oak death (SOD). Five tanoak trees at the site were infected with the EU1 strain of Phytophthora ramorum, the pathogen that causes SOD. The pathogen can infect many plants but kills tanoak. The new site is just beyond the current 515-square-mile SOD quarantine area on the north shore of the Rogue River. Located within the Rogue River-Siskiyou National Forest, the site is near the Myrtle Tree Trail and about six miles north of the nearest known sudden oak death infestation.
The USDA Forest Service identified the infected trees from high-resolution aerial imagery as a part of the annual USDA Forest Service/Oregon Department of Forestry (ODF) Aerial Detection Survey. The trees identified were sampled by ODF crews who sent samples to the Oregon State University’s Forest Pathology Lab. After the initial test at OSU showed P. ramorum, DNA samples were sent on April 14 to the ODA Plant Health Lab in Salem. The ODA Plant Health Lab is certified by the USDA to perform official confirmatory testing for P. ramorum. The lab confirmed the samples as presumptive positives on April 16. As per federal protocol, the samples have been shipped to the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service Lab in Maryland for final confirmation. New infestation sites must be confirmed by APHIS’ Plant Protection Quarantine unit before regulatory action may take place. In the meantime, the Oregon Department of Forestry and USDA Forest Service SOD crews have marked off an area 1,000 feet from the sampled trees and are looking for more trees with signs of the disease. Until treatment begins, SOD crews will continue to heavily monitor the area for the presence of infested trees and plants. The area will also be monitored on an ongoing basis by aerial disease survey experts. Oregon regulations require a property officially confirmed as infested with SOD to undergo eradication treatments. In Oregon, federal land managers cooperate with the Oregon Departments of Forestry and Agriculture to carry out eradication treatments on infested sites on federal lands. Federal funds are available to cover the cost of treating the area, which is now the highest priority site for the SOD program. Treatment consists of cutting, piling, and burning all tanoaks. ODA maintains the Phytophthora ramorum Quarantine, which allows any area in the state to be placed under quarantine where a SOD infestation is confirmed (OAR 603-052-1230(2)(d). Thus, an emergency quarantine order does not need to be issued. Oregon’s SOD Program will consult with stakeholders regarding any potential expansion of quarantine boundaries. USDA Forest Service staff are evaluating whether access restrictions to recreation use in the treatment area might be needed. Background: The invasive non-native pathogen that causes the sudden oak death (SOD) in tanoak was first detected in Oregon in 2001. A plant quarantine of the area was promptly set up, which has gradually expanded to cover almost a third of Curry County. When attempts to eradicate the disease – which can survive on several native and non-native plant species – proved impossible, Oregon’s SOD program switched to slowing the spread of the disease. In 2010, a Generally Infested Area (GIA) within the quarantine area was created. Within that zone, where the disease is well established, eradication treatments are no longer required. The GIA was enlarged in late 2020 and now covers 123 square miles within the quarantine area; it is about 19 miles north to south and nine miles east to west. In Europe, the EU1 strain of P. ramorum has been found to damage and kill several conifer species, including Douglas-fir, western hemlock, grand fir, and larch. That strain was first found in Oregon in 2015 within the existing quarantine area. Infestations of the EU1 strain are aggressively treated with the goal of local eradication. Read more about sudden oak death at https://www.oregon.gov/ODF/Documents/ForestBenefits/SOD.pdf.