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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #366358
Research Project: Biology, Epidemiology, and Detection of Emerging Plant Pathogenic Oomycetes

Location: Foreign Disease-Weed Science Research

Title: Rapid recovery and detection of Phytophthora ramorum propagules in nursery water

Author
item Luster, Douglas - Doug
item SHARMA, SUPRIYA - Dominican University Of California
item SCHWEIGKOFLER, WOLFGANG - Dominican University Of California
item SUSLOW, KAREN - Dominican University Of California

Submitted to: Sudden Oak Death Science Symposium
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2020
Publication Date: 2/12/2022
Citation: Luster, D.G., Sharma, S., Schweigkofler, W., Suslow, K. 2020. Rapid recovery and detection of Phytophthora ramorum propagules in nursery water. Sudden Oak Death Science Symposium. 83-90. https://www.fs.usda.gov/treesearch/pubs/60509.

Interpretive Summary: Phytophthora ramorum, causal agent of sudden oak death, continues to threaten U.S. forest ecosystems and the nursery industry. Rapid methods are needed for recovery and detection of P. ramorum propagules from water sources. Working at the National Ornamental Research Site at Dominican University of California, we are developing rapid methods for recovery and detection of P. ramorum from nursery irrigation water. Results with spiked samples indicate that P. ramorum recovered by from nursery water samples can be detected in 24 h or less, significantly reducing the time for diagnostic labs to report results to regulatory agencies.

Technical Abstract: Phytophthora ramorum, causal agent of sudden oak death, continues to threaten U.S. forest ecosystems and the nursery industry. Currently, USDA APHIS‘s protocol utilizes the Bottle of Bait (BOB) recovery method for P. ramorum, which requires collecting water from a source, baiting with healthy rhododendron leaves for a 3-day incubation period, followed by plating on semi-selective media. Rapid methods are needed for recovery and detection of P. ramorum propagules from water sources. Working at the National Ornamental Research Site at Dominican University California, we are developing rapid water filtration and flocculation methods for recovery and detection of P. ramorum propagules from nursery irrigation water. A mock irrigation pond was established with flow from a P. ramorum- infested plot into an adjoining plot. Antibodies raised against P. ramorum -specific secreted proteins were applied for detection of zoospores and sporangia from 1 L samples in filter extracts or alum flocculates using standard immunoassay procedures. Results with spiked samples indicate that propagules of P. ramorum recovered by filtration or flocculation from spiked nursery water samples can be detected in 24 h or less.