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Abstract
Coast redwood
(Sequoia sempervirens) is a host for
Phytophthora ramorum but it is unclear if the pathogen represents a significant disease risk to this tree species. In an on-going field experiment, we are examining the prevalence of infection and the development of symptoms on coast redwood seedlings in naturally infested sites in southern Humboldt Co., California. In November 2006, healthy redwood seedlings were placed amid tanoak and bay trees naturally infected with
P. ramorum. Disease incidence and symptom development are being observed monthly, and every two months, a subset of redwood seedlings is destructively sampled to investigate the location and extent of tissue colonization by
P. ramorum. In order to correlate inoculum levels across field sites with disease development, rainwater is being collected and baited with rhododendron leaves to determine presence and frequency of positive
P. ramorum rain traps. Results of this study will help evaluate the risk of
P. ramorum to coast redwood seedlings and inform land managers of the potential for reforestation of infested sites with this species.
Parent Publication
Citation
Lucas, S.; Parke, J.; Valachovic, Y. 2009. Prevalence and development of disease on coast redwood seedlings caused by
Phytophthora ramorum. 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: 292-295.
