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Abstract
From 2001 through 2006 stem cankers on tanoak (
Lithocarpus densiflorus) were sampled during surveys to detect and eradicate
Phytophthora ramorum from forests in southwestern Oregon. Pieces of bark from stem canker margins were plated on cornmeal agar amended with 10 ppm natamycin, 200 ppm Na-ampicillin, and 10 ppm rifampicin.
P. ramorum was usually identified on the isolation plates by the presence of characteristic hyphae, chlamydospores, and sporangia. Other colonies resembling
Phytophthora were isolated into pure culture and identified by examination of morphological features and by DNA sequence analysis.
Phytophthora species other than
P. ramorum isolated from tanoak stem cankers include
P. cambivora,
P. cinnamomi,
P. species "Pgchlamydo,"
P. gonapodyides,
P. nemorosa, P. pseudosyringae, and
P. siskiyouensis. Additional isolates may represent new species of
Phytophthora and have not yet been identified. Selected isolates were tested for pathogenicity by inoculating healthy tanoak stems. Lesion margins were plated for re-isolation of the pathogen.
Parent Publication
Citation
Reeser, Paul; Sutton, Wendy; Hansen, Everett . 2009.
Phytophthora species associated with tanoak stem cankers in southwestern Oregon. In: Goheen, E.M.; Frankel, S.J., tech. coords. Proceedings of the fourth meeting of the International Union of Forest Research Organizations (IUFRO) Working Party S07.02.09: Phytophthoras in forests and natural ecosystems. Gen. Tech. Rep. PSW-GTR-221. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 87-90.
