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Sudden oak death
Introduction
Phytophthora ramorum is a plant pathogen that has been identified as the causative agent of sudden oak death (SOD). P. ramorum was first observed in Marin County, California in 1995 on tanoak (Lithocarpus densiflorus). The pathogen now infects native hosts in 14 counties along California coast and in Curry County in southwestern Oregon where it has caused widespread dieback of tanoak and other oak species. P. ramorum has also been found infecting horticultural plants at nurseries in California, Oregon, and Washington and also in Europe and Canada. A complete host list (pdf, 4 KB) for SOD is maintained by the United States Department of Agriculture, Animal and Plant Health Inspection Service (USDA, APHIS).




Description
Sudden Oak Death is caused by the fungal-like plant pathogen Phytophthora ramorum. Members of the genus Phytophthora are not fungi, but rather water molds in the taxonomic class Oomycete. They posses asexual reproductive zoospores with flagella that are utilized in movement to infect new hosts. P. ramorum differs from most members of the genus in the ability to spread aerially while maintaining the characteristic movement in soil and water. Other microscopic features of the pathogen include drought resistant resting bodies called chlamydospores, and the sexual spores termed oospores.
 
Signs of this fungal-like plant pathogen are not easily viewed without a microscope. Plant symptoms may be the first indication of P. ramorum infestation for the public. The University of California, Cooperative Extension and Agriculture Experiment Station maintains a descriptions and images of plant hosts symptoms that may be helpful in recognizing the disease.
 

Regulations
The Oregon Department of Agriculture (ODA) first began surveying Oregon nurseries for SOD in 2001, with the advent of the quarantine in Curry county. Surveying continued in 2002 with no positive finds for P. ramorum. The pathogen was first found in 2003 at nurseries in Clackamas, Jackson, and Washington counties. Nursery crops infected included Camellia, Pieris, Rhododendron, and Viburnum species. The affected nurseries were placed on quarantine until all infected material was destroyed, delimitation surveys completed, and 90 day monitoring found no sign of the disease. In 2004, the pathogen was detected in 23 nurseries and the USDA confirmed Nursery Protocol was initiated for positive nurseries. Protocol included immediate quarantine of positive nurseries, delimitation surveys to assess the extent of the infection, destruction of all positive plant material, survey monitoring, trace forward surveys, and trace back surveys.

On January 10, 2005, the USDA Federal Order went in effect, regulating the movement of nursery stock from Oregon, California, and Washington nurseries. The purpose of the Order is to prevent the spread and dissemination of P. ramorum through the horticultural trade. Effective January 10, 2005, host and associated host nursery stock may not be moved interstate from any commercial nursery in Oregon unless the nursery enters into a USDA Compliance Agreement and a USDA certificate accompanies the shipment.

Currently, nurseries are required to enter into compliance with the USDA. Nurseries first must complete and mail a USDA compliance agreement. An ODA representative will then sample host material or complete a visual inspection for non-host plants. A USDA seal will be provided after the nursery has been declared SOD-free. The seal signifies the plant material originates from a nursery that has been inspected, tested, and found free of P. ramorum and that the nursery has entered into a compliance agreement with the USDA. This seal must be included with shipping documents when exporting host material. Once this process is completed, the nursery will be listed on the P. ramorum free list located on the ODA web site. An annual SOD inspections is required to maintain current compliance with the USDA.
 
Recipients of tree and shrub nursery stock imported into the state of Oregon from any out-of-state source are also required to notify the ODA. This information assists ODA personnel in SOD monitoring of host material imported to Oregon. Notification shall be via mail, FAX or e-mail to: Nursery Program Supervisor, Plant Division, Oregon Department of Agriculture, 635 Capitol St. NE, Salem, OR 97301; FAX 503-986-4564

Federal compliance agreement instructions
To enter into the Federal Compliance Agreement:
 
  1. Download the federal compliance agreement (pdf, 228 KB)
  2. Complete blocks 1, 2, 6, 7, & 8 on the first page of the agreement. Fill in your name and sign the appropriate line on page 6.
  3. Mail pages 1 through 6 of the compliance agreement to: Ken Ball, USDA PPQ, Airport Business Center, 6135 NE 80th Ave. Suite A, Portland, Oregon 97218

A copy of the completed compliance agreement will be returned to you along with instructions on how to obtain USDA certificates. Please contact Ken Ball 503/986-4644 if you need additional information.
Sudden oak death free lists
Comprehensive list of nurseries that are currently in the USDA Compliance Agreement:

Oregon nurseries approved to ship host nursery stock.
Oregon nurseries approved to ship non-host nursery stock
California nurseries approved to ship host and non-host nursery stock
Washington nurseries approved to ship host and non-host nursery stock

Additional information