Pacific Southwest

Title: Ecology of Phytophthora nemorosa and Phytophthora pseudosyringae in mixed-evergreen forests

Author: Wickland, Allison C.; Rizzo, David M.

Date: 2006

Source: In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 73-75

Station ID: GTR-PSW-196

Description: Recent research has shown that Phytophthora ramorum is a major threat to CaliforniaÂ’s coast live oak (Quercus agrifolia) dominated, mixed-evergreen forests (Rizzo and Garbelotto 2003). However, the role that diseases caused by other Phytophthora species play in the ecology of these forest communities is less evident. Surveys in mixed-evergreen forests have revealed two additional Phytophthora species, P. nemorosa and P. pseudosyringae. In these forests, P. nemorosa, P. pseudosyringae and P. ramorum are all aerial, canker-causing pathogens with overlapping host and geographic ranges. Although all three pathogens seem to share a similar ecological niche, P. nemorosa and P. pseudosyringae are not associated with landscape level tree mortality. Additionally, the geographic distribution of P. nemorosa and P. pseudosyringae extends beyond the known distribution of P. ramorum. This study was initiated to learn more about the role of P. nemorosa and P. pseudosyringae in the ecology of mixed-evergreen forests and to gain an understanding of the dynamics of these forests prior to P. ramorum invasion. In this paper we address the incidence and mortality levels associated with P. nemorosa and P. pseudosyringae and describe biotic and abiotic variables associated with pathogen presence.

Keywords: mixed-evergreen forest, Phytophthora nemorosa, Phytophthora pseudosyringae, Phytophthora ramorum

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Citation

Wickland, Allison C.; Rizzo, David M.  2006.  Ecology of Phytophthora nemorosa and Phytophthora pseudosyringae in mixed-evergreen forests.   In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 73-75.