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Animal and Plant Health Inspection Service
U.S. Department of Agriculture
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Listing and Regulation of Plant Species Reported to be Proven Hosts of and Plants Associated with Phytophthora ramorum (P. ramorum)

October 31, 2022

To: State and Territory Agricultural Regulatory Officials

Effective immediately, APHIS is adding proven hosts and associated plants to the list of plant species regulated for P. ramorum. The pathogen, P. ramorum, is the cause of both Sudden Oak Death, a forest disease that has resulted in widespread dieback of several tree species in California and Oregon forests, and Ramorum Blight, which affects the leaves and twigs of numerous other plants in forests and nurseries. This action is necessary to control the artificial spread of P. ramorum.

Regulated establishments and nurseries in quarantine areas, as defined in Title 7 of the Code of Federal Regulations (CFR) § 301.92-3 that operate under a compliance agreement may continue to ship proven hosts and associated plants on the updated regulated list, as stated in their current compliance agreement, until the next compliance inspection. Nurseries under compliance must provide the September 2022 list of proven hosts and associated plants of P. ramorum at their nursery to regulatory officials prior to the next compliance inspection. At the next compliance inspection, regulatory officials must inspect, potentially sample, and test proven hosts and associated plants. All plants on the proven host and associated plant list must be determined free from P. ramorum before they are shipped.

The attached Federal Order identifies the hosts added to the list of plant species regulated for P. ramorum. In addition, please see the updated “APHIS Lists of Proven Hosts of and Plants Associated with Phytophthora ramorum” dated September 2022, which may be found at this site:

USDA APHIS | Phytophthora ramorum

For more information about APHIS’ P. ramorum regulatory program, please contact the P. ramorum National Policy Manager, William Wesela, at (301) 851-2229.


Dr. Mark L Davidson
Deputy Administrator
Plant Protection and Quarantine

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