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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research » Research » Publications at this Location » Publication #361434

Research Project: Integrated Disease Management of Exotic and Emerging Plant Diseases of Horticultural Crops

Location: Horticultural Crops Research

Title: Diversity of foliar Phytophthora species on Rhododendron in Oregon nurseries

item Knaus, Brian
item Graham, Kimberly - Oregon State University
item Grunwald, Niklaus - Nik
item Fieland, Valerie - Oregon State University

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/15/2016
Publication Date: 3/1/2017
Citation: Knaus, B.J., Graham, K.A., Grunwald, N.J., Fieland, V.J. 2017. Diversity of foliar Phytophthora species on Rhododendron in Oregon nurseries. In: Proceedings of the Sudden Oak Death Sixth Science Symposium; 6/20/16-6/23/16; San Francisco, CA. Available: 76 p.

Interpretive Summary:

Technical Abstract: The genus Phytophthora contains some of the most notorious plant pathogens affecting nursery crops. Given the recent emergence of the sudden oak death pathogen Phytophthora ramorum, particularly in association with Rhododendron spp., characterization of Phytophthora communities associated with this host in nursery environments is prudent. Many taxa may present symptoms similar to P. ramorum but we do not necessarily know their identity, frequency, and importance. Here, we present a survey of Phytophthora taxa observed from seven nurseries in the U.S. state of Oregon. Incidence and diversity of Phytophthora communities differed significantly among nurseries and among seasons within nursery (Knaus and others 2015). The taxa P. syringae and P. plurivora were widespread and detected at most of the nurseries sampled. Nine other taxa were also detected but were found either in a single nursery or were shared among only a few nurseries. Characterization of the Phytophthora communities present in nurseries is an important step toward understanding the ecology of these organisms as well as an aid to nursery managers in determining what risks may be present when symptomatic plants are observed. This study builds on an increasing literature, which characterizes Phytophthora community structure in nurseries.