Diseases caused by phytophthora species are recurrent challenges in nursery production in the U.S. The release of infected plant material into trade and natural ecosystems have been well documented…

Diseases caused by phytophthora species are recurrent challenges in nursery production in the U.S. The release of infected plant material into trade and natural ecosystems have been well documented with p. Ramorum, the causal agent of sudden OAK death, which resulted in massive DIE-offs of native species in the forest and caused significant losses due to plant diseases and quarantine measures in infected nursery stock traded from west coast nurseries to the rest of the U.S. Since the mid 90's. Once plant pathogens are introduced into national trade or natural ecosystems via infected plant stock, costs associated efforts to control pathogen spread are beyond $100 billion per year in the united states. With this, the most cost-effective approach is to prevent and monitor the introduction of plant pathogens into nursery production. The purpose of this agreement is to develop rapid and sensitive diagnostic assays to detect phytophthora species in nursery irrigation and surface water for early detection applications. Specific goals include an evaluation of a filtration assay developed by luster ET AL. (2020) to detect p. Ramorum spores from water, combined with a rapid recombinase polymerase amplification (RPA) assay, for the detection of several phytophthora species recurrent in nursery production. Following, the efficacy of the method in detection of phytophthora species and p. Ramorum will be evaluated in a simulated nursery water system and compared with traditional baiting methods used for water testing of phytophthora species. Finally, the method will be evaluated for the detection of phytophthora in leachate water collected from infected plant material. Sub-awardees include DR. Douglas luster (USDA-ARS), who will provide technical support and advice to a post-doctoral researcher (UC davis) in the development and execution of experiments to test the RPA assays in water, and DR. Wolfgang schweigkofler (national ornamental research site at dominican university of california; nors-DUC), who will coordinate and provide logistics support for the experiments that will be conducted at the nors-DUC simulated nursery water system. The expected outcomes of this work include the development of new diagnostic methods that will benefit nursery growers, regulatory agencies, diagnostics laboratories, and extension personnel by determining in a timely manner if nursery plant stock is infected with phytophthora pathogens.