Natural stem infection of Lawson cypress ( Chamaecyparis lawsoniana ) caused by Phytophthora ramorum

Phytophthora ramorum

Consequences of Phytophthora ramorum Infection in Coast Live Oaks

Sudden oak death, caused by Phytophthora ramorum, has infected and killed large numbers of oaks (Quercus spp.) and tanoaks (Lithocarpus densiflorus) in California since the mid 1990s. Since March 2000 we have been investigating the interactions between patterns of disease progression and broader landscape-scale patterns of disease incidence and expansion in study plots in Marin County. The inci...

Chemistry of Coast Live Oak Response to Phytophthora ramorum Infection

Since the mid 1990s, Phytophthora ramorum has been responsible for the widespread mortality of tanoaks, as well as several oak species throughout California and Oregon forests. However, not all trees die, even in areas with high disease pressure, suggesting that some trees may be resistant to the pathogen. The apparent resistance to P. ramorum infection of some individuals within coast live oak...

Correlating Phytophthora ramorum Infection Rate and Lesion Expansion in Tanoak

To date, resistance to Phytophthora ramorum in its most susceptible hosts has most commonly been quantified by lesion growth, after wounding or non-wounding inoculations via mycelia or high concentrations of zoospores. However, even highly susceptible hosts may not always become infected when they are exposed to a pathogen under ecologically realistic conditions. Therefore, resistance quantifie...

Phytophthora ramorum in North America

Two apparently unlinked events marked the beginning of one of the most devastating forest diseases known to man in recent times: Sudden Oak Death (SOD). In the mid 1990s, while a novel species of Phytophthora was being isolated from mildly diseased Rhododendron and Viburnum plants in German and Belgian nurseries, the first reports of inexplicable death of tanoaks (Notholithocarpus densiflorus) ...