Federal quarantine regulations for Phytophthora ramorum are developed by the United States Department of Agriculture – Animal and Plant Health Inspection Service (USDA-APHIS). The entire states of California, Oregon, and Washington are regulated to limit the spread of P. ramorum from nurseries. Additional quarantine regulations are in place in the 15 California counties and partial area of Oregon with wildland infestations. See the map at right or download a printable copy. In 2013 & 2014 the regulations were modified: Federal Order DA-2013-27  dropped certification requirements (annual inspections, sampling, and testing) for non-host nurseries in the regulated areas of CA, OR, and WA  and  Federal Order DA-2014-02 targets high-risk nurseries (recently and/or recurrently positive in the past 3 years) and requires an enhanced compliance program. Find more information at the USDA-APHIS P. ramorum page.

California and other states

The California state Phytophthora ramorum quarantine harmonizes with the federal regulation. The California Department of Food and Agriculture (CDFA) implements quarantine policy for California with enforcement conducted by county agriculture departments.  See more detail on California’s statewide quarantine on the CDFA website. Businesses or individuals with questions concerning movement of host nursery stock, firewood or other materials made from host trees or plants can contact their county agricultural commissioner’s office – see the California County Contacts page for more information.

Oregon Department of Agriculture

Washington Department of Agriculture

Nursery regulations

The National Plant Board is a non-profit organization of the plant pest regulatory agencies of each of the states and Commonwealth of Puerto Rico. Regulations for the shipment of nursery and greenhouse stock for each of the 50 states are available at

International quarantines

To prevent further introductions of P. ramorum, the  United States regulates importation of nursery stock into the USA. See the April 18, 2012 order from APHIS for more information.

Canadian Food Inspection Agency (CFIA)

UK Food and Environment Research Agency (FERA)

UK Forestry Commission (FC)

International standards require pest risk assessments to evaluate the need for quarantines. Phytophthora ramorum risk assessments from several countries are available on our Pest Risk Assessments page.

* This page was updated in 2012. Regulatory information previous to that time is stored in our Historical Archive.