scholarly journals Sudden Oak Death Taking a Toll on U.S. West Coast

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Kate Wheeling

Researchers have been modeling effects of the plant pathogen Phytophthora ramorum on coastal forests in California and Oregon since it arrived on the West Coast 3 decades ago.

2009 ◽  
Vol 99 (6) ◽  
pp. 739-749 ◽  
Author(s):  
S. Prospero ◽  
N. J. Grünwald ◽  
L. M. Winton ◽  
E. M. Hansen

Phytophthora ramorum (oomycetes) is the causal agent of sudden oak death and ramorum blight on trees, shrubs, and woody ornamentals in the forests of coastal California and southwestern Oregon and in nurseries of California, Oregon, and Washington. In this study, we investigated the genetic structure of P. ramorum on the West Coast of the United States, focusing particularly on population differentiation potentially indicative of gene flow. In total, 576 isolates recovered from 2001 to 2005 were genotyped at 10 microsatellite loci. Our analyses of genetic diversity and inferences of reproductive mode confirm previous results for the Oregon and California populations, with the strong majority of the genotypes belonging to the NA1 clonal lineage and showing no evidence for sexual reproduction. The high incidence of genotypes shared among populations and the lack of genetic structure among populations show that important large-scale, interpopulation genetic exchanges have occurred. This emphasizes the importance of human activity in shaping the current structure of the P. ramorum population on the West Coast of the United States.


HortScience ◽  
2004 ◽  
Vol 39 (7) ◽  
pp. 1677-1680 ◽  
Author(s):  
Tamar Y. Harnik ◽  
Monica Mejia-Chang ◽  
James Lewis ◽  
Matteo Garbelotto

Phytophthora ramorum (Oomycota) (Werres et al., 2001) is the plant pathogen responsible for the lethal disease of several oak species in California known as sudden oak death. The pathogen also causes a foliar disease on Umbellularia californica (bay laurel or simply bay). Bay leaves have been identified as the major source of natural inoculum in California coastal woodlands. Because of the epidemiological relevance of bay leaves, their movement needs to be regulated. Our study shows that P. ramorum is highly heat tolerant and can be reisolated from artificially inoculated bay laurel leaves placed at 55 °C for up to 1 week. The pathogen cannot be recovered after 2 weeks at 55 °C. Prolonged heat treatments, however, are impractical for bay leaves intended to be sold commercially as a spice, since they negatively impact the quality of the leaves. Here we describe a treatment involving a progressive and gradual heating process combined with the application of moderate vacuum. This method can be completed in 22 hours and is shown here to eliminate the recovery of P. ramorum without having a negative impact on the quality of the bay leaves.


2016 ◽  
Vol 546 ◽  
pp. 31-45 ◽  
Author(s):  
E Infantes ◽  
L Eriander ◽  
PO Moksnes
Keyword(s):  

Author(s):  
S.M. Thomas ◽  
M.H.Beare C.D. Ford ◽  
V. Rietveld

Humping/hollowing and flipping are land development practices widely used on the West Coast to overcome waterlogging constraints to pasture production. However, there is very limited information about how the resulting "new" soils function and how their properties change over time following these extreme modifications. We hypothesised that soil quality will improve in response to organic matter inputs from plants and excreta, which will in turn increase nutrient availability. We tested this hypothesis by quantifying the soil organic matter and nutrient content of soils at different stages of development after modification. We observed improvements in soil quality with increasing time following soil modification under both land development practices. Total soil C and N values were very low following flipping, but over 8 years these values had increased nearly five-fold. Other indicators of organic matter quality such as hot water extractable C (HWC) and anaerobically mineralisable N (AMN) showed similar increases. With large capital applications of superphosphate fertiliser to flipped soils in the first year and regular applications of maintenance fertiliser, Olsen P levels also increased from values


2016 ◽  
Vol 93 (1) ◽  
pp. 26-44
Author(s):  
Larry Schweikart ◽  
Lynne Pierson Doti

In Gold Rush–era California, banking and the financial sector evolved in often distinctive ways because of the Gold Rush economy. More importantly, the abundance of gold on the West Coast provided an interesting test case for some of the critical economic arguments of the day, especially for those deriving from the descending—but still powerful—positions of the “hard money” Jacksonians.


2019 ◽  
Vol 21 (2) ◽  
pp. 1006-1018
Author(s):  
Ana Alexandre Santos Rodrigues ◽  
Francisco Asis Aquino Bezerra Filho ◽  
Jáder Onofre de Morais ◽  
Lidrana De Souza Pinheiro

As práticas de campo proporcionam aos discentes uma proximidade com o cotidiano. A metodologia proposta no estudo sugere uma divulgação simplificada do conhecimento cientifico da Planície Litorânea de Almofala, propondo rotas de acesso didáticas para práticas de campo que auxiliem os professores das escolas de Itarema. Para a complementação teórica foram considerados como base os inventários da Geodiversidade cientifica do litoral oeste do estado do Ceará, realizados no âmbito do projeto PRONEX. Isso foi feito por pesquisadores de várias Instituições de Ensino Superior do Ceará, e a literatura clássica local. Enquanto resultados discutidos, considerou-se que estes roteiros de práticas de campo podem ser estabelecidos e decididos em conjunto, entre professores e alunos. Tendo como base o mapa interpretativo dos roteiros, com intuito de realizar o reconhecimento e entendimento da dinâmica costeira.Palavras-chave: Educação; Geodiversidade; Planície Litorânea. ABSTRACTField practices provide students with a closeness to daily life. The methodology proposed in the study suggests a simplified dissemination of scientific knowledge of the Almofala Coastal Plain, proposing didactic access routes for field practices that help teachers of Itarema schools. For theoretical complementation, the inventories of the scientific geodiversity of the west coast of the state of Ceará, carried out under the PRONEX project were considered. It was done by researchers from various Higher Education Institutions in Ceará, and its local classical literature. As results discussed, it was considered that these field practice roadmaps can be jointly established and decided between teachers and students. Based on the interpretative map of the roadmaps, in order to recognize and understand the coastal dynamics.Keywords: Education; Geodiversity; Coastal plain. RESUMENLas prácticas de campo ofrecen a los estudiantes una cercanía a la vida diaria. La metodología propuesta en el estudio sugiere una divulgación simplificada del conocimiento científico sobre la llanura costera de Almofala, proponiendo rutas de acceso didáctico para prácticas de campo que ayudan a los docentes de las escuelas de Itarema. Para la complementación teórica fueron considerados como información base los inventarios de la geodiversidad científica de la costa oeste del estado de Ceará, realizados en el ámbito del proyecto PRONEX. Fue realizado por investigadores de varias instituciones de educación superior en Ceará, y la literatura clásica local. En cuanto a los resultados discutidos, se consideró que estas hojas de ruta de prácticas de campo pueden ser establecidas y escogidas conjuntamente entre docentes y estudiantes, con base en el mapa interpretativo de ruta, con el fin de reconocer y comprender la dinámica costera de esta región.Palabras clave: Educación; Geodiversidad; Llanura costera.


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