01788nas a2200193   4500008004100000022001400041245011400055210006900169260001200238300001600250490000700266520115800273100001701431700001901448700001801467700002201485700001801507856006901525       2014                        eng d  a0191-291700aLineage, Temperature, and Host Species have Interacting Effects on Lesion Development in Phytophthora ramorum0 aLineage Temperature and Host Species have Interacting Effects on  c12/2014  a1717 - 17270 v983 a<p>There are four recognized clonal lineages of the pathogen <em>Phytophthora ramorum</em>. The two major lineages present in North America are NA1 and NA2. With a few exceptions, NA1 is found in natural forest ecosystems and nurseries, and NA2 is generally restricted to nurseries. Isolates from the NA1 and NA2 lineages were used to infect rhododendron, camellia, and California bay laurel in detached leaf assays to study the effects of lineage, temperature, and host on pathogenicity and host susceptibility. Isolates within both lineages were highly variable in their ability to form lesions on each host. There was also a tendency toward reduced lesion size in successive trials, suggesting degeneration of isolates over time. Temperature had a significant effect on lesion size, with a response that varied depending on the host and isolate. Phenotypic differences between lineages appear to be heavily influenced by the representation of isolates used, host, and temperature. The importance of temperature, host, and lineage are discussed with respect to disease management, as well as future range expansions and migrations of the pathogen.</p>1 aEyre, C., A.1 aHayden, K., J.1 aKozanitas, M.1 aGrünwald, N., J.1 aGarbelotto, M  uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-02-14-0151-RE02247nas a2200157   4500008004100000022001400041245009700055210006900152260001600221300001200237490000800249520172800257100001701985700001802002856006902020       2015                        eng d  a0031-949X00aDetection, Diversity, and Population Dynamics of Waterborne Phytophthora ramorum Populations0 aDetection Diversity and Population Dynamics of Waterborne Phytop  cJan-01-2015  a57 - 680 v1053 a<p>Sudden oak death, the tree disease caused by <em>Phytophthora ramorum</em>, has significant environmental and economic impacts on natural forests on the U.S. west coast, plantations in the United Kingdom, and in the worldwide nursery trade. Stream baiting is vital for monitoring and early detection of the pathogen in high-risk areas and is performed routinely; however, little is known about the nature of water-borne <em>P. ramorum</em> populations. Two drainages in an infested California forest were monitored intensively using stream-baiting for 2 years between 2009 and 2011. Pathogen presence was determined both by isolation and polymerase chain reaction (PCR) from symptomatic bait leaves. Isolates were analyzed using simple sequence repeats to study population dynamics and genetic structure through time. Isolation was successful primarily only during spring conditions, while PCR extended the period of pathogen detection to most of the year. Water populations were extremely diverse, and changed between seasons and years. A few abundant genotypes dominated the water during conditions considered optimal for aerial populations, and matched those dominant in aerial populations. Temporal patterns of genotypic diversification and evenness were identical among aerial, soil, and water populations, indicating that all three substrates are part of the same epidemiological cycle, strongly influenced by rainfall and sporulation on leaves. However, there was structuring between substrates, likely arising due to reduced selection pressure in the water. Additionally, water populations showed wholesale mixing of genotypes without the evident spatial autocorrelation present in leaf and soil populations.</p>1 aEyre, C., A.1 aGarbelotto, M  uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-07-13-0196-R