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Abstract
Bay laurel (
Umbellularia californica (Hook. & Arn.) Nutt.) is the primary reservoir host of
Phytophthora ramorum Werres, De Cock & Man n?t Veld in coastal California woodlands. Non-lethal foliar lesions on bay laurel trees support the majority of pathogen sporulation during the winter et season and appear to provide the primary means of surviving through California?s arid Mediterranean summers. Previous experiments have shown that the proportion of symptomatic bay leaves from which
P. ramorum can be successfully isolated decreases during the summer. In addition, isolation of
P. ramorum from bay laurel leaves was less at the end of the dry season within mixed evergreen forests when compared to redwoodtanoak forests. These experiments also suggested a positive correlation between bay laurel stem water potential and summer isolation frequency from leaves. A more thorough understanding of the environmental and physiological constraints on the summer survival of
P. ramorum will assist in the development of SOD risk assessments.
Parent Publication
Citation
DiLeo, M.V.; Bostock, R.M.; Rizzo, D.M. 2008. Effects of environmental variables on the survival of
Phytophthora ramorum in bay laurel leaves. In: Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M., tech. coords. 2008. Proceedings of the sudden oak death third science symposium. Gen. Tech. Rep. PSW-GTR-214. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. pp. 345-346
