Impact of weather variables and season on sporulation of Phytophthora pluvialis and Phytophthora kernoviae     

Stuart Fraser  Mireia Gomez‐Gallego  Judy Gardner  Lindsay S. Bulman  Sandra Denman  Nari M. Williams 《Forest Pathology》2020,50(2)

Phytophthora pluvialis and Phytophthora kernoviae are the causal agents of important needle diseases on Pinus radiata in New Zealand. Little is known about the epidemiology of the diseases, making the development of control strategies challenging. To investigate the seasonality and climatic drivers of sporulation, inoculum traps, consisting of pine fascicles floating on water in plastic containers, were exchanged fortnightly at five sites in P. radiata plantations between February 2012 and December 2014. Sections of needle baits were plated onto selective media and growth of Phytophthora pluvialis and P. kernoviae recorded. To explore the generalizability of these data, they were compared to detection data for both pathogens from the New Zealand Forest Health Database (NZFHDB). Further, equivalent analyses on infection of Rhododendron ponticum by P. kernoviae in Cornwall, UK allowed the comparison of the epidemiology of P. kernoviae across different host systems and environments. In New Zealand, inoculum of P. pluvialis and P. kernoviae was detected between January–December and March–November, respectively. Inoculum of both species peaked in abundance in late winter. The probability of detecting P. pluvialis and P. kernoviae was greater at lower temperatures, while the probability of detecting P. pluvialis also increased during periods of wet weather. Similar patterns were observed in NZFHDB data. However, the seasonal pattern of infection by P. kernoviae in the UK was the opposite of that seen for sporulation in New Zealand. Phytophthora kernoviae was likely limited by warmer and drier summers in New Zealand, but by colder winter weather in the UK. These results emphasize the importance of considering both environmental drivers and thresholds in improving our understanding of pathogen epidemiology.  相似文献   

Filtration of Green Algae and Cyanobacteria by Freshwater Mussels in the Partitioned Aquaculture System     

Kevin R.  Stuart Arnold G.  Eversole David E.  Brune 《Journal of the World Aquaculture Society》2001,32(1):105-111

Abstract.— The freshwater mussel Elliptio complanata was provided water containing green algae and cyanobacteria delivered from the Partitioned Aquaculture System (PAS) at eight flow rates to determine algal filtration rates as mg of particulate organic carbon (POC)/kg wet tissue weight per h. The dominant taxon in cyanobacterial waters was Microcystis while the dominant taxa in green algal waters were Scenedesmus and Ankistrodesmus . The cell counts of Scenedesmus and Ankistrodesmus were the only algal taxa that were significantly different between the incoming water and water filtered by mussels. Filtration rates of POC obtained from green algal water were significantly greater than from cyanobacteria-dominated waters at all flow rates. A significant increase in mean filtration rate was observed as flow rates increased. The filtration rate of green algae increased as POC concentration increased, peaking at 28 mg C/L. A maximum filtration rate was not observed with cyanobacterial waters.  相似文献   

Examination of faecal samples as a method of identifying pollen exposure in dogs.     

M A Fraser  E Caulton  P E McNeil 《The Veterinary record》2001,149(14):424-426

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Arthropathy associated with Brucella abortus strain 19 vaccination in cattle. II. Experimental studies     

M J Corbel  F A Stuart  R A Brewer  M Jeffrey  R Bradley 《The British veterinary journal》1989,145(4):347-355

Attempts to reproduce in calves the arthropathy associated with Brucella abortus strain 19 (S19) vaccination by direct intra-articular injection of S19 or virulent Brucella cells were unsuccessful. Intra-articular injection of rabbits and a calf with immune complexes isolated from the synovial fluid of a field case produced clinical and histological signs of arthropathy accompanied by the development of rheumatoid factor.  相似文献   

Response to Liposome-Encapsulated Doxorubicin (TLC D-99) in a Dog With Myeloma     

William C. Kisseberth  E. Gregory MacEwen  Stuart C. Helfand  David M. Vail  Cheryl L. London  Evan Keller 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1995,9(6):425-428

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Selenium response in dairy cattle     

Tasker JB  Bewick TD  Clark RG  Fraser AJ 《New Zealand veterinary journal》1987,35(8):139-140

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Hyperthermia in cattle associated with tall fescue (Festuca arundinacea)     

Brookbanks EO  Bell KC  Fraser D  Kearns MP  Sutherland RJ 《New Zealand veterinary journal》1985,33(4):57-58

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Testing the serving capacity of beef bulls     

Fraser D 《New Zealand veterinary journal》1983,31(3):40

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“Publish and be damned”     

A. F. Fraser 《Veterinary research communications》1980,4(1):1-2

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Effects of area and isolation of woodland patches on herbaceous plant species richness across Great Britain   总被引：5，自引：2，他引：5  

Petit  Sandrine  Griffiths  Leila  Smart  Simon S.  Smith  Geoff M.  Stuart  Rick C.  Wright  Simon M. 《Landscape Ecology》2004,19(5):463-471

Richness of Ancient Woodland Indicator plant species was analysed in 308 woodland patches that were surveyed during the Countryside Survey of Great Britain carried out in 1998. The Countryside Survey recorded vegetation plots and landscape structure in 569 stratified 1 km sample squares and developed a remotely-sensed land cover map of the UK. Using these datasets, we tested the hypothesis that Ancient Woodland Indicator species richness in woodland fragments was limited by patch area, shape and spatial isolation and that woodland patches located in the lowland region of Great Britain would respond differently than those in the upland region. The variation in Ancient Woodland Indicator species richness in the British lowlands (n = 218) was mainly explained by patch area and two measures of connectivity, the length of hedgerows and lines of trees in the 1 km square and the area of woodland within 500 m of the vegetation plot. By contrast, variation in Ancient Woodland Indicator species richness in the British uplands (n = 90) was related to Ellenberg scores of the vegetation communities sampled – a surrogate for habitat quality – and no significant effect of spatial structure was detected. It therefore appears that the degree of fragmentation of woodland in the British lowlands limits the distribution of Ancient Woodland Indicator species, while in the uplands, failed colonisation is a matter of habitat quality rather than a result of landscape structure.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献