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Inexpensive humidity chambers, equipped with spore traps, were designed for the study of various ecological phenomena. The basic apparatus enables cycling conditions of any desired humidity with a period of high humidity with or without leaf wetness; and two conditions of air movement through the chamber, each of them chosen in the range of 0 to 14 1/min. The chamber’s performance was tested withUromyces phaseoli on beans in relation to (a) the duration of leaf wetness needed for infection, (b) the effect of relative humidity on the appearance of sori. and (c) the amount of sori and the number of uredospores produced. Iiberated and trapped under various conditions of relative humidity. 相似文献
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Ewa Matyjaszczyk 《Pest management science》2015,71(4):485-491
Prevention methods can still be a cost‐effective and efficient tool for pest control. Rational use of prevention methods is a feasible way to reduce dependency on chemical protection in agriculture. Costs, workload and farmers' awareness are key issues, however. In Poland, crop rotation is used as a method for pest control only to a limited extent owing to the high share of cereals in the crop structure. The choice of resistant varieties is satisfactory, but farmers should make use of qualified seed material more often. Liming is recommended on the majority of farms on account of widespread soil acidity. Favourable aspects as regards the prevention of pest development are biodiversity and the popularity of prevention cultivation techniques. © 2014 Society of Chemical Industry 相似文献
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S. ORLANDINI G. ZIPOLI B. GOZZINI E. EGGER E. MARINELLI P. STORCHI 《EPPO Bulletin》1991,21(3):431-439
In intensive viticulture, the distribution of the principal meteorological elements depends principally on aspect, slope and altitude. The present research aims to examine microclimate modelling in vineyards, by connecting local atmospheric conditions with macroscale meteorological conditions as reported by the standard meteorological networks. To study the effect of topography on crop microclimate, vineyard temperature has been measured with an infrared thermometer, and phenological, allometrical and yield measurements have been made in vineyards located close to the Chianti Classico hills (IT). The climatic and pathological data has been used to verify mathematical models simulating microclimatic conditions and to protect grapevines from downy mildew (Plasmopara viticola). The models allow a reduction in the number of treatments against the disease, lightening at the same time the damage to the ecosystem and the cost for the farmer. 相似文献
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乳状液被广泛应用于食品、石油、化妆品和农用化学品等领域,稳定性是影响其使用寿命和功能发挥的关键因素。因此,快速、准确地表征乳状液的稳定性一直被人们所关注。农药水乳剂是以乳状液为基础的农药剂型之一,具有高效、低毒和环保等优点。文章简要介绍了乳状液在食品和石油等领域的应用及研究现状,重点综述了液滴粒径及其分布测定、电导率测定、微观结构研究、拟三元相图研究和液滴表面电动性能研究等表征乳状液制备与使用过程中稳定性的主要手段,并总结了这些表征手段在农药水乳剂研究开发中的应用情况,旨在为缩短水乳剂配方研制周期和提高其稳定性提供参考。 相似文献
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Irene Camacho Rubina Leça Duarte Sardinha Roberto Camacho Magdalena Sadyś 《European journal of plant pathology / European Foundation for Plant Pathology》2018,150(4):955-969
The genus Puccinia represents rust infections, which are responsible for great productivity losses in crops of commercial and ornamental plants worldwide. This work is aimed at determining the occurrence of Puccinia spp. spores in Madeira Island in order to infer the exposure risks from a phytopathological point of view. A phytopathological analysis was performed in 203 local plant samples between January 2003 and December 2012. During the same period the airborne concentrations of rust spores were monitored following well-established guidelines. Aerobiological data was compared with meteorological records. Based on macro and microscopic analyses, five species of rusts were identified: P. horiana, P. buxi, P. porri, P. pelargonii-zonalis, and P. sorghi, and they were found mostly in spring and summer. A total of 20 samples out of 203 analysed plants (9.8%), were infected with Puccinia spores, i.e., P. horiana (5.9%), P. buxi (1.47%), P. porri and P. pelargonii-zonalis (0.98%), and P. sorghi (0.5%). During the studied period Puccinia spores attained an annual average concentration of 126 spores m?3 and most of them were recorded between March and October. Meteorological factors were determinant in fluctuations in spore concentration. Relative humidity was the parameter that favoured the biggest release and dispersal of the rust spores, whereas rainfall revealed a significant negative effect. Rusts do not represent an important plant pathogen in Madeira Island, as shown by the low infection frequencies and levels of airborne spore concentrations. 相似文献
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Soil persistence of selected sugar-beet herbicides and their combinations with lenacil 总被引:1,自引:0,他引:1
Laboratory studies on the degradation of several sugar-beet herbicides both singly and in combination with lenacil were conducted in four soils. First-order kinetics were used to describe the breakdown rates of lenacil, benzthiazuron, carbetamide, propham and phenmedipham, and their combinations with lenacil. Mean half-lives of the herbicides ranged from 14 days for propham to 191 days for benzthiazuron. There were no significant differences between the herbicides applied singly or in combination. Persistance dans le sol de plusieurs herbicides de la betterave et leurs combinaisons avec le lenacil Pour quatre types de sols, nous avons étudié, au laboratoire, la dégradation de plusieurs herbicides de la betterave appliqués seuls ou avec du lenacil. Des cinétiques de première ordre ont été utilisées pour calculer les taux de dégradation des herbicides suivants: lenacil, benzthiazuron, carbetamide, prophame, phenmediphame et de leurs combinaisons avec du lenacil. Les temps moyens de rémanence des herbicides se situaient entre 14 jours pour le prophame et 191 pour le benzthiazuron. Nous n'avons trouvé aucune difference significative entre les herbicides appliqués seuls et avec du lenacil. 相似文献
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Peter Jeschke 《Pest management science》2016,72(2):210-225
The synthesis of propesticides is an important concept in design of modern agrochemicals with optimal efficacy, environmental safety, user friendliness and economic variability. Based on increasing knowledge of the biochemistry and genetics of major pest insects, weeds and agricultural pathogens, the search for selectivity has become an ever more important part of pesticide development and can be achieved by appropriate structural modifications of the active ingredient. Propesticides affect the absorption, distribution, metabolism and excretion parameters, which can lead to biological superiority of these modified active ingredients over their non‐derivatised analogues. Various selected commercial propesticides testify to the successful utilisation of this concept in the design of agrochemicals. This review describes comprehensively the successful utilisation of propesticides and their role in syntheses of modern agrochemicals, exemplified by selected commercial products coming from different agrochemical areas. © 2015 Society of Chemical Industry 相似文献
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代谢组学研究的是生物体系受到内在和外在因素刺激产生的内源性代谢变化。近年来,随着代谢组学在病原真菌致病机理、真菌与植物互作以及新型生物活性物质开发研究领域的应用,真菌代谢组学越来越受到国内外的重视,同时也取得了较大的进展。由于丝状真菌类型和研究目的的差异,其研究方法不尽相同。本文主要综述近年来国内外丝状真菌代谢组学分析方法的研究进展,从丝状真菌样品制备、代谢物鉴定、数据分析、生物标志物发掘、代谢通路方面进行概述,以期为该领域研究者提供参考,进一步推进代谢组学在真菌研究领域中的应用。 相似文献
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负水头供水盘埋设方式对番茄生长和水分利用率的影响 总被引:2,自引:0,他引:2
以番茄为材料,于温室内采用负水头供水盆栽装置进行试验,研究了供水盘不同埋设方式对番茄生长和水分利用率的影响,旨在为负水头灌溉技术应用于蔬菜栽培提供依据。试验设置3个处理,单盘倾角9°埋设于根系底部(处理Ⅰ)、单盘竖向埋设于根系一侧(处理Ⅱ)和双盘埋设于根系两侧(处理Ⅲ)。结果表明:处理Ⅱ控制的土壤含水量有利于控制植株长势、增加茎粗和叶片数量、降低番茄植株耗水量,显著提高水分利用率;处理Ⅱ分别与处理Ⅰ和Ⅲ相比,单株番茄增产12.70%和15.45%,节水18.14%和13.70%。结果表明,单盘竖向埋设于根系一侧为最佳供水盘埋设方式,可获得高产、节水的效果。 相似文献
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J. CONNOLLY 《Weed Research》1988,28(6):431-436
The implications of recent studies on the inappropriatness of replacement series and additive methods in competition studies, and some possible alternatives, are discussed in the context of weed research, Replacement series are usually inadequate to assess competitive interactions and can be misleading. In particular they may be biased in favour of the larger species. Many of the criticisms of replacement series also apply to additive experiments. Response models relating yield per individual to the densities of the species in the mixture provide methodology for answering many questions about mixtures. This paper proposes a framework for using these models to: (i) measure the effect of weed species on yield per individual and yield per unit area for the crop and weed species; (ii) develop methods of biological control of weeds both within a seaons and over seasons, based on the interference between crop and weed species and the population biology of the weed species; (iii) establish a cost-benefit analysis of certain of the biological weed-control programmes. The inclusion of the effect of relative emergence time and management practices in response models is considered as well as experimental design for crop-weed experiments. 相似文献
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We evaluated whether new information could be drawn from additional data collection and unconventional statistical analyses of an on-farm trial. First, we compared a conventional sampling method using a biomass estimate of weed abundance to repeated visual assessment of the percentage ground cover of weeds. The biomass was sampled once after the treatment, whereas the ground cover was repeatedly sampled once before weed control plus several occasions after weed control. Second, we contrasted the outcomes from analysis of variance ( anova ), taking samples from a single point in time with repeated measures (rm) anova and a multivariate method. As the outcomes and conclusions drawn were relatively similar, we conclude that the ground cover estimate of weed abundance was as reliable as the biomass estimate. The rm anova enabled us to follow the temporal trend in response to treatments in the most abundant species, including possible initial differences. Multivariate analysis went even further, by clearly displaying species-wise responses and treatment selectivity. 相似文献
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ZERAATPISHEH Mojtaba 《干旱区科学》2019,11(4):551-566
Natural soil-forming factors such as landforms, parent materials or biota lead to high variability in soil properties. However, there is not enough research quantifying which environmental factor(s) can be the most relevant to predicting soil properties at the catchment scale in semi-arid areas. Thus, this research aims to investigate the ability of multivariate statistical analyses to distinguish which soil properties follow a clear spatial pattern conditioned by specific environmental characteristics in a semi-arid region of Iran. To achieve this goal, we digitized parent materials and landforms by recent orthophotography. Also, we extracted ten topographical attributes and five remote sensing variables from a digital elevation model (DEM) and the Landsat Enhanced Thematic Mapper (ETM), respectively. These factors were contrasted for 334 soil samples (depth of 0-30 cm). Cluster analysis and soil maps reveal that Cluster 1 comprises of limestones, massive limestones and mixed deposits of conglomerates with low soil organic carbon (SOC) and clay contents, and Cluster 2 is composed of soils that originated from quaternary and early quaternary parent materials such as terraces, alluvial fans, lake deposits, and marls or conglomerates that register the highest SOC content and the lowest sand and silt contents. Further, it is confirmed that soils with the highest SOC and clay contents are located in wetlands, lagoons, alluvial fans and piedmonts, while soils with the lowest SOC and clay contents are located in dissected alluvial fans, eroded hills, rock outcrops and steep hills. The results of principal component analysis using the remote sensing data and topographical attributes identify five main components, which explain 73.3% of the total variability of soil properties. Environmental factors such as hillslope morphology and all of the remote sensing variables can largely explain SOC variability, but no significant correlation is found for soil texture and calcium carbonate equivalent contents. Therefore, we conclude that SOC can be considered as the best-predicted soil property in semi-arid regions. 相似文献
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John M. Osgerby 《Pest management science》1974,5(3):327-340
The basic components of a general-purpose analogue computer are described in terms of their operational functions. Their use in pesticide research has been extremely limited but such examples as exist are reviewed. Examples of the use of analogue computers are given. These include the simulation of single and consecutive first-order reactions, the sorption-desorption processes affecting the availability of pesticides in soils, diffusion and leaching in soils and the build-up of residues in soils following repeated annual applications to the soil surface. 相似文献
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