Jennifer M. Davidson

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The newly discovered Phytophthora ramorum canker disease of oak (Sudden Oak Death Syndrome) threatens millions of acres of California woodlands where coast live oak (Quercus agrifolia), tanoak (Lithocarpus densiflorus), or black oak (Quercus kelloggii) are dominant species. An important step in controlling this disease involves understanding how it is(More)
A new canker disease of Lithocarpus densiflorus, Quercus agrifolia, Q. kellogii, and Q. parvula var. shrevei in California is shown to be caused by Phytophthora ramorum. The pathogen is a recently described species that was previously known only from Germany and The Netherlands on Rhododendron and Viburnum. This disease has reached epidemic proportions in(More)
Sudden oak death (SOD) has been shown to be caused by a new species of Phytophthora, P. ramorum. A basic understanding of the genetics of P. ramorum is critical to any management strategy. We have initiated a number of studies to examine species concepts, population biology and mating behavior of the pathogen. Based on a number of morphological features(More)
The remaining native flora of Hawaii are under continuing pressure from habitat loss and exotic, invasive organisms, including animals, plants, and pathogens. In order to assess the risk to P. ramorum, we inoculated seedlings of Metrosideros polymorpha (ohia), Vaccinium calycinum (ohelo), Acacia koa (koa), and Leptecophylla tameiameiae (pukiawe) with the(More)
As climate change challenges organismal fitness by creating a phenotype-environment mismatch, phenotypic plasticity generated by epigenetic mechanisms (e.g., DNA methylation) can provide a temporal buffer for genetic adaptation. Epigenetic mechanisms may be crucial for sessile benthic marine organisms, such as reef-building corals, where ocean acidification(More)
Sudden oak death manifests as non-lethal foliar lesions on bay laurel (Umbellularia californica), which support sporulation and survival of Phytophthora ramorum in forest ecosystems. Infected bay laurel leaves are more likely to abscise than uninfected leaves, resulting in an accumulation of inoculum at the forest floor. The pathogen survives the dry(More)
In a case study, we evaluated observers' accuracy in detecting Phytophthora ramorum and their ability to estimate percentage of infested area in coast live oak (Quercus agrifolia) stands in California. The study compared visual detection of symptoms on California bay laurel (Umbellularia californica) and oaks with results from three permanent 1-hectare(More)
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