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We describe the spatial epidemiology of Varroa destructor infestation among honey bee apiaries in the greater Auckland area of the North Island of New Zealand. The study population was comprised of 641 apiaries located within the boundaries of the study area on 11 April 2000. Cases were those members of the study population declared Varroa-infested on the basis of testing conducted between April and June 2000. The odds of Varroa was highest in apiaries in the area surrounding transport and storage facilities in the vicinity of Auckland International Airport. A mixed-effects geostatistical model, accounting for spatial extra-binomial variation in Varroa prevalence, showed a 17% reduction in the odds of an apiary being Varroa infested for each kilometre increase in the squared distance from the likely site of incursion (95% Bayesian credible interval 7–28%). The pattern of spatially autocorrelated risk that remained after controlling for the effect of distance from the likely incursion site identified areas thought to be ‘secondary’ foci of Varroa infestation initiated by beekeeper-assisted movement of infested bees. Targeted investigations within these identified areas indicated that the maximum rate of local spread of Varroa was in the order of 12 km/year (interquartile range 10–15 km/year). 相似文献
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选用AG50W-X8阳离子交换树脂,并以批处理的方式,成功地将蜂蜜中的肽类物质与其它组合得到了分离。抗褐变实验结果清楚地表明,蜂蜜中的肽类成分完全没有抑制褐变的活性。这与以前的报道截然不同。 相似文献
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Incorporation of a range of higher concentrations of CuSO4·5H2O in MS medium [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassay with 240 tobacco tissue cultures. Physiol. Plant 15, 473–497] significantly enhanced direct shoot bud induction and proliferation from cultured leaf and nodal explants taken from mature plants of Stevia rebaudiana. Shoot bud induction medium was supplemented with BAP (2.2 μM) and IAA (2.8 μM). When the concentration of CuSO4·5H2O in the induction medium was raised to 0.5 μM (five times the MS level, i.e. 0.1 μM) there was significant increase in percentage response along with increase in shoot bud number per explant. The shoots were healthy, well developed with dark green broader leaves. There was remarkable increase in total biomass and chlorophyll content at increased (0.5 μM) copper level in the medium. During proliferation stage also presence of high copper levels in the medium favoured increase in shoot bud number per explant. 相似文献
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Kathryn L. Ford Béatrice Henricot Kendra Baumgartner Andy M. Bailey 《The Journal of Horticultural Science and Biotechnology》2017,92(1):39-47
Armillaria (honey fungus) is a virulent necrotrophic pathogen that causes Armillaria root disease. Conventional Armillaria inoculation assays use young saplings as hosts and consequently are cumbersome, frequently conducted outdoors, and take many years from establishment to analysis of infection. We have developed and evaluated a faster inoculation assay for Armillaria that uses herbaceous plants as hosts, is carried out in controlled conditions, and reduces experimental durations to 3 months. Plant species of known susceptibility to Armillaria and comparisons between virulent A. mellea and opportunistic A. gallica were used to validate the assay. Mortality and diagnostic symptoms of Armillaria root disease such as epiphytic rhizomorphs and mycelial fans were used to assess levels of infection. We also attempted to reduce assay preparation time by substituting woody inocula with agar inocula, but typical symptoms of Armillaria root disease were only observed on plants infected with woody inocula. Through our assay, we identified five new potential herbaceous hosts of Armillaria: Kniphofia hirsuta, Hordeum vulgare, Lobelia cardinalis, Nicotiana tabacum and Helenium hoopesii – further expanding the extensive list of plants with susceptibility to Armillaria and suggesting infection of herbaceous species may be more widespread than currently acknowledged. 相似文献
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厚皮甜瓜果实井水预冷特性研究 总被引:2,自引:1,他引:2
探讨了不同初始温度、果实大小、成熟度及不同瓜水体积比例对甜瓜预冷速度的影响。结果表明,果实初始温度、比表面积、果肉厚度、瓜水比例均影响降温速度。预冷时间与果实初始温度、果肉厚度和冷却介质比例均呈正相关关系,与果实比表面积呈负相关关系。冷却介质比例相同时,流动水的预冷效率显著高于半流动水。预冷期间果实温度(T)与预冷时间(t)的关系可用函数()21/tzTTaem-=-来描述。 相似文献