103 research outputs found

    The impact and control of Phytophthora cinnamomi in native and rehabilitated forest ecosystems in Western Australia

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    Botanists have likened the impact of Phytophthora cinnamomi in Australian plant communities to that of the last ice age, which affected a large number of plant families, genera and species within these families. Phytophthora cinnamomi affects the floristics and structure of many unique plant communities. We discuss the impact of this pathogen and our current knowledge of its biology, genetics and pathology in Western Australian plant communities and the current management strategies used to limit its spread and impact. We hope that the knowledge obtained from some of our experiences in managing this pathogen in Western Australian natural ecosystems will be of some benefit to researchers studying Phytophthora diseases in Quercus, Alnus and Castanea in Europe and America

    Pathogenicity of Phytophthora multivora to Eucalyptus gomphocephala and E. marginata

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    Since the early 1990s there has been a significant decline of E. gomphocephala, and more recently E. marginata, in the tuart forest in tuart woodland in Yalgorup National Park SW Western Australia, although no satisfactory aetiology has been established to explain the decline. Characteristics of the canopy dieback and decline distribution are reminiscent of other forest declines known to involve Phytophthora soil pathogens and indicate that a Phytophthora species may be involved in the decline. In 2007 isolates of Phytophthora multivora, recently described by (1), were recovered from rhizosphere soil of declining or dead trees of Eucalyptus gomphocephala and E. marginata. For E. gomphocephala and E. marginata, the pathogenicity of P. multivora was tested: ex situ on seedlings using a soil infestation method; and in situ on stems using an under bark infestation method

    Phytophthora multivora sp. nov., a new species recovered from declining Eucalyptus, Banksia, Agonis and other plant species in Western Australia

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    A new Phytophthora species, isolated from rhizosphere soil of declining or dead trees of Eucalyptus gomphocephala, E. marginata, Agonis flexuosa, and another 13 plant species, and from fine roots of E. marginata and collar lesions of Banksia attenuata in Western Australia, is described as Phytophthora multivora sp. nov. It is homothallic and produces semipapillate sporangia, smooth-walled oogonia containing thick-walled oospores, and paragynous antheridia. Although morphologically similar to P. citricola, phylogenetic analyses of the ITS and cox1 gene regions demonstrate that P. multivora is unique. Phytophthora multivora is pathogenic to bark and cambium of E. gomphocephala and E. marginata and is believed to be involved in the decline syndrome of both eucalypt species within the tuart woodland in south-west Western Australia

    Repositioning of the global epicentre of non-optimal cholesterol

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    High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol—which is a marker of cardiovascular risk—changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million–4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.</p

    Repositioning of the global epicentre of non-optimal cholesterol

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    High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol�which is a marker of cardiovascular risk�changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95 credible interval 3.7 million�4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world. © 2020, The Author(s), under exclusive licence to Springer Nature Limited

    Rising rural body-mass index is the main driver of the global obesity epidemic in adults

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    Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)

    The effect of phosphite (phosphonate) on Phytophthora cinnamommi zoospore prouction in planta

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    P. cinnamomi is a major pathogen in Western Australia's native vegetation. Phosphite is a cheap fungicide which is non-toxic to animals and has been shown to protect Western Australian plant species against P. cinnamomi. It is proposed to use phosphite in the Eucalyptus marginata forest and in rehabilitated minesites, to control spot infections of P. cinnamomi and to prevent the spread of the pathogen into non-infected plant communities. Movement of zoospores downslope from an infected area via swimming and transport in surface and subsurface water is thought to be one of the main modes of spread by the pathogen. It is not known whether phosphite is able to inhibit or prevent P. cinnamomi from producing zoospores in planta. If the fungus is still able to produce large numbers of zoospores it may be capable of spreading even if an area has been sprayed with phosphite. The aim of this experiment was to determine the effect of phosphite on the production of zoospores from E. marginata and Banksia grandis seedlings which were inoculated with P. cinnamomi

    Control of Phytophthora cinnamomi by the fungicide phosphite in relation to in planta phosphite concentrations and phytotoxicity in native plant species in Western Australia

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    Low volume aerial phosphite applications has been used in recent years at rates of up to 24 kg ha-1 to protect native plant species and communities threatened by Phytophthora cinnamomi while the recommended rate for spray to run-off phosphite application is 5 g L-1. Phosphite uptake and in planta phosphite concentrations in native plant species may vary considerably between species and with application rate as may the effectiveness of disease control and the duration of this control. Phytotoxicity symptoms post-spray include foliar necrosis, defoliation, growth abnormalities and chlorosis, reduced root growth and reproductive effects and these may also vary considerably between species. Phytotoxicity symptoms increase with increasing application rate but are generally mild at recommended rates. However, a percentage of species in the plant communities assessed show greater sensitivity to phosphite. Aerial phosphite application rates for native plant communities aims to maximise in planta phosphite concentrations in Phytophthora-susceptible species for disease control while minimising phytotoxicity symptoms in the species present
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