TY - JOUR T1 - Efficacy of phosphonic acid, metalaxyl-M and copper hydroxide against Phytophthora ramorum in vitro and in planta JF - Plant Pathology Y1 - 2009 A1 - Garbelotto, M. A1 - Harnik, T. Y. A1 - Schmidt, D. J. KW - disease management KW - phenotypic variability KW - Quercus agrifolia KW - Sudden oak death KW - Umbellularia californica AB -

The ability of metalaxyl-M, phosphonic acid in the form of phosphonate, and copper hydroxide to inhibit different stages in the life cycle of Phytophthora ramorum, the causal agent of sudden oak death (SOD), was tested in vitro using 12 isolates from the North American forest lineage. In addition, experiments were conducted in planta to study the ability of phosphonic acid injections and metalaxyl-M drenches to control pathogen growth on saplings of California coast live oak (Quercus agrifolia), and of copper hydroxide foliar sprays to control infection of California bay laurel (Umbellularia californica) leaves. Phytophthora ramorum was only moderately sensitive to phosphonic acid in vitro, but was highly sensitive to copper hydroxide. In planta experiments indicated the broad efficacy of phosphonic acid injections and of copper hydroxide sprays in preventing growth of P. ramorum in oaks and bay laurels, respectively. Finally, although metalaxyl-M was effective in vitro, drenches of potted oak trees using this active ingredient were largely ineffective in reducing the growth rate of the pathogen in planta.

PB - Blackwell Publishing Ltd VL - 58 UR - http://dx.doi.org/10.1111/j.1365-3059.2008.01894.x ER - TY - JOUR T1 - Non-oak native plants are main hosts for sudden oak death pathogen in California. JF - Cal Ag Y1 - 2003 A1 - Garbelotto, M. A1 - Davidson, J. A1 - K. Ivors A1 - Maloney, P. A1 - Hüberli, D. A1 - Koike, S. A1 - Rizzo, D. AB -

The finding of Phytophthora ramorum — the pathogen that causes sudden oak death in four California native trees — on rhododendron in Europe led us to hypothesize that its host range in California’s natural forests was much greater than previously suspected. In addition to the affected oak species, we have now identified an additional 13 species from 10 plant families that act as hosts for P. ramorum in California. Our data indicates that nearly all of the state’s main tree species in mixed-evergreen and redwood-tanoak forests — including the coniferous timber species coast redwood and Douglas fir — may be hosts for P. ramorum. The broad host range of P. ramorum, the variability of symptoms among different hosts and the ability of the pathogen to disperse by air suggests that it may have the potential to cause long-term, landscape-level changes in California forests.

VL - 57 UR - http://ucanr.org/repository/cao/landingpage.cfm?article=ca.v057n01p18&abstract=yes ER - TY - JOUR T1 - First report on an infestation of Phytophthora cinnamomi in natural oak woodlands of California and its differential impact on two native oak species JF - Plant Disease Y1 - 2006 A1 - Garbelotto, M. A1 - Huberli, D. A1 - Shaw, D. VL - 90 UR - http://apsjournals.apsnet.org/doi/abs/10.1094/PD-90-0685C ER -