Fusarium wilt of the Canary Island Date Palm ( Phoenix canariensis ) caused by Fusarium oxysporum f. sp. canariensis was recorded for the first time in several locations in Victoria. The identity of ...the fungus was substantiated using a polymerase chain reaction-based technique with primers specific for this particular pathogen.
Wollemia nobilis is an ancient coniferous tree species that was recently discovered in eastern Australia. This tree is highly threatened due to its limited distribution. No genetic variation has been ...detected within the wild populations of ~100 adult plants. A recent study has revealed that a species of Botryosphaeria is highly pathogenic to W. nobilis . The aim of the present study was to identify this fungus, as well as Botryosphaeria isolates of unknown identity from other Southern Hemisphere coniferous hosts, Araucaria from New Zealand and Widdringtonia from South Africa. To facilitate their identification, sequence data for the ITS rDNA, as well as the β-tubulin and translation elongation factor 1-α genes were combined to determine the phylogenetic relationship of these isolates with those of known Botryosphaeria spp. Isolates from W. nobilis included two Botryosphaeria spp. The first is closely related to B. ribis , but also shares some unique sequence polymorphisms with B. parva. One isolate grouped with B. australis , but also varied slightly from this taxon in the gene regions analysed. Additional isolates will be needed to determine whether these sequence variations represent speciation events or merely variation within populations of B. ribis and B. australis. In addition to this, B. parva was identified from Araucaria in New Zealand, and B. australis was found on Widdringtonia trees in South Africa. All three reports of these fungi are new records for their various hosts and could represent important pathogens of these trees.
This study explores the pathways of salt and water movement from the landscape to the stream across major landforms, in dryland areas of south eastern Australia. It was conducted at the Livingstone ...Creek catchment (∼43
km
2) a sub catchment of the Kyeamba catchment, NSW, Australia. An extensive stream salinity field monitoring network between major landforms was developed and data capture occurred from 2002 to 2004. Additional measurements of surface water isotopes were also taken to independently assess responses observed from the detailed monitoring network and assist in determining the sources of water. Flow and salt mass balances were calculated across four gauging stations for each event. The stream monitoring found patterns of salt delivery to streams were consistent during four monitored stream events. In the hill slope and colluvial fill, lower sloped, meta-sediment landforms, stream salinity responses showed the classical salinity response to an event: an initial increase of salinity at the beginning of an event (due to first flush) which then diminished as a consequence of dilution. The main difference between these landforms was that the colluvial fill lower sloped meta-sediments had sodic, low permeability soils near the stream edge. This lead to (1) less variation in stream salinities during event conditions and (2) during low base flow increases in stream salinity occurred as concentrated salts from the stream banks dissolved. For the flatter, alluvial landforms, the salinity response showed quite a different and contrasting temporal pattern: salinity continued to increase and vary directly with flow during events. For all the landforms, base flow salinity increases as flow diminished after a event although salinity responses were more lagged in the alluvial landform. This different salinity pattern in the alluvial landform is attributed to (1) for event flow, the increased contributions of more saline subsurface lateral flow of soil water from the alluvial landform compared to very fresh direct surface runoff sourced from hillslope landforms upstream and (2) for base flow, seepage of near stream alluvial groundwater through the stream banks that was less saline then the base flow water sourced upstream from the hillslope landforms. The stream water isotope values confirm the above findings by showing that, in the alluvial landforms soil water contributions are important during events and that direct surface runoff with little interaction of soil water occurs from the hill slope landforms during events. Conceptual models describing salt and water movement through the different landforms and under different antecedent catchment wetness conditions are presented. These conceptual models develop our understanding of water and solute (salt) pathways through the landscape to the stream. To date, this is one of the few experimental studies in Australia connecting landscape and stream salinisation.
The Silicon photomultiplier-based Compton Telescope for Safety and Security (SCoTSS) has been developed incorporating end-user requirements into the design process. The end-user group includes those ...responsible for mobile survey in the event of a radiological or nuclear accident, those responsible for radiation survey support to security operations at major events and at Canadian borders, as well as some of those responsible for Canadian defense applications. The SCoTSS development program has reached a technology readiness level of eight, and we are proceeding with field trials of the instrument in high-fidelity operational environments. Prospective end users have been involved in trial set up and execution, assuring applicability in their mission spaces. SCoTSS has been subject to trials involving hidden sources, heavily shielded sources, imager moving with respect to source, and complicated man-made surroundings. Our operators value high sensitivity for anomaly geolocation and mapping. End users also require an instrument which is capable of direction reconstruction in motion, as well as rapid imaging of a field of view. We have developed a “time to image” measure which allows for quantitative comparison of imagers of fundamentally different technology, where one design may have an advantage in terms of energy resolution and compactness and another design may have an advantage in terms of efficiency and cost effectiveness. We present here the performance of the SCoTSS imager in rapid direction finding. As well, we compare the time to image quantity for the SCoTSS imager and the H3D Polaris-H Quad imager where the data were taken under equivalent conditions. This quantitative measure of imaging performance can allow operators to make an informed choice of the design that meets their needs taking into consideration also weight and size as well as budgetary constraints.
Fusarium wilt of the Canary Island Date Palm (Phoenix canariensis), caused by Fusarium oxysporum f.sp. canariensis, was recorded for the first time in South Australia. The identity of the fungus was ...substantiated using a polymerase chain reaction-based technique with primers specific for this particular pathogen.PUBLICATION ABSTRACT
Fusarium wilt of Phoenix canariensis (Canary Island Date Palm) is caused by Fusarium oxysporum f. sp. canariensis (Foc). The disease occurs worldwide, including Australia where hundreds of palms have ...been killed. Isolates of Foc were collected from fronds of diseased palms at sites around Sydney and different parts (non-frond) of individual palms within a site. Three techniques were used to assess diversity of these isolates; vegetative compatibility groupings, PCR testing for a sequence previously shown to be associated with pathogenicity and DNA fingerprinting using ERIC primers. The combined methods divided the isolates into one major and four minor groups, with two of the minor groups showing some bridging characters. ERIC PCR showed these groups to be different from six overseas isolates of Foc, five of which belonged to VCG 0240. A minority of isolates did not fall into any group and are presumed saprophytes. Some discrepancies in the expected correlation between the techniques occurred for the non-frond isolates; this has implications for appropriate tissue selection for disease diagnosis. The number of groups and the differences between them indicate a degree of diversity comparatively higher than that shown in other studies for this forma specialis and may have important consequences for disease management.
The location and distribution of landform shape and size describe and categorize many features of a catchment. Landforms indicate soil types, arability of land, geological features, hydrological ...influences, and even shallow groundwater systems. This paper describes an objective method for delineating major landforms of a catchment on the basis of hydrological terrain analysis. It allows comparisons to be made within and between catchments. The method uses the UPNESS index from the Fuzzy Landscape Analysis Geographic Information System (FLAG) model (Roberts et al., 1997) that is derived from digital elevation data. UPNESS was developed as an index of surface and shallow subsurface water accumulation. In the method presented in this paper, we fit a five-parameter sigmoidal function to the cumulative distribution function (cdf) of the natural log (ln) of UPNESS. The point of inflection of the cdf of the UPNESS index is defined from the first derivative of the five-parameter sigmoidal function as the point of maximum concavity. The second and third points are defined by determining the maximum upward concavity and minimum downward concavity from the second derivative of a five-parameter sigmoidal function (referred to as break points). The inflection and break points from the UPNESS index are used to segment the cdf into three regions that represent four different landform elements. Landform categories based on these points represent ridge tops and upper slopes, midslopes, lower slope, and in-filled valley/alluvial deposits. The shape of the cdf curve indicates the dominance of major landforms within a catchment, providing an objective means for classifying this catchment characteristic. Examples are given showing how landform discrimination compares to geological maps. The landforms index presented in this study offers a useful technique for differentiating complex landforms from a landscape using terrain analysis that attempts to represent dominant hydrological soil formation processes.
DNA fingerprints, based on Enterobacterial Repetitive Intergenic Consensus (ERIC) sites, were investigated as an alternative technique to Vegetative Compatibility Grouping (VCG) in studying ...populations of Fusarium oxysporum Schlecht. emend. Snyd. & Hans. Isolates of F. oxysporum were recovered from orchids displaying visible signs of root rot. Fifty-two isolates were collected and analysed using both the ERIC DNA fingerprinting technique and Vegetative Compatibility Grouping. Isolates were divided into 17 ERIC groups and 37 VCG groups. Based on its lower level of sensitivity and its rapid and reproducible result, the ERIC DNA fingerprinting was found to be a more appropriate technique for studying diverse populations of F. oxysporum.PUBLICATION ABSTRACT
Fusarium wilt of Phoenix canariensis (Canary Island Date Palm) is caused by Fusarium oxysporum f. sp. canariensis (Foc). The disease occurs worldwide, including Australia where hundreds of palms have ...been killed. Isolates of Foc were collected from fronds of diseased palms at sites around Sydney and different parts (non-frond) of individual palms within a site. Three techniques were used to assess diversity of these isolates; vegetative compatibility groupings, PCR testing for a sequence previously shown to be associated with pathogenicity and DNA fingerprinting using ERIC primers. The combined methods divided the isolates into one major and four minor groups, with two of the minor groups showing some bridging characters. ERIC PCR showed these groups to be different from six overseas isolates of Foc, five of which belonged to VCG 0240. A minority of isolates did not fall into any group and are presumed saprophytes. Some discrepancies in the expected correlation between the techniques occurred for the non-frond isolates; this has implications for appropriate tissue selection for disease diagnosis. The number of groups and the differences between them indicate a degree of diversity comparatively higher than that shown in other studies for this forma specialis and may have important consequences for disease management.PUBLICATION ABSTRACT
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