The sudden oak death pathogen, Phytophthora ramorum, is present in southwestern
Oregon, and while an eradication effort is underway, the potential impact of the
polyphagous pathogen on surrounding vegetation is unknown. Plant communities in the
area are substantially different from those affected in California, although tanoak
(Lithocarpus densiflorus), evergreen huckleberry (Vaccinium ovatum) and Pacific
rhododendron (Rhododendron macrophyllum) are hosts found in both areas. Other
species are likely to be susceptible to the pathogen. Detached leaf and whole plant assays
were used to test species commonly associated with tanoak, as well as three rare or
endemic ericaceous species of the western Siskiyou Mountains and their associated taxa.
Leaves and plants were challenged with zoospore suspensions that were capable of
generating symptoms in the known hosts tanoak and evergreen huckleberry. Most (78%)
of the previously unchallenged species developed necrotic lesions in detached leaf assays
although severity (% leaf area necrotic) was variable. All three of the ericaceous species
of conservation concern: Arctostaphylos hispidula, Kalmiopsis leachiana, and Leucothoe
davisiae were susceptible in detached leaf assays. Factors important in determining
whether or not these species will become infected in their native habitat are discussed. / Graduation date: 2004
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/31178 |
| Date | 26 September 2003 |
| Creators | Zanzot, James W. |
| Contributors | Parke, Jennifer L. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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