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1.
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   

2.
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   

3.
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   

4.
5.
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   

6.
统计分析在植物病害研究上的应用   总被引:1,自引:1,他引:1  
简述数理统计在国内、外应用于植物病害田问试验、抽样技术、预测预报、为害损失、时空分析和病害鉴定研究的主要成果.针对信息技术的发展在数理统计分析方法的重要作用,对数理统计应用软件的前景进行了分析,提出了数理统计应用软件网络化、集成化和数据挖掘的发展趋势.  相似文献   

7.
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   

8.
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   

9.
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   

10.
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   

11.
寄生蜂是重要的害虫寄生性天敌,在害虫的生物防治中发挥着巨大作用。结合国际上的研究热点,对寄生蜂产卵引诱物从寄生蜂寻找寄主的3个阶段:栖境偏好、栖境定位、寄住定位等方面进行了阐述。  相似文献   

12.
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   

13.
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   

14.
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   

15.
抗草甘膦杂草及其检测方法发展现状   总被引:4,自引:0,他引:4  
草甘膦在世界范围的多年大量使用已经引起了抗草甘膦杂草的产生。本文针对全球迄今为止发现的21种抗草甘膦杂草的发生、发展状况进行了论述。探讨了抗草甘膦杂草抗药性检测方法,分别从整株生物测定及生物化学等方面介绍了抗草甘膦杂草检测方法的研究现状,为抗草甘膦杂草检测方法的发展及其抗性监测方法的建立提供参考。  相似文献   

16.
我国水果防腐保鲜剂的使用及其检测方法   总被引:3,自引:0,他引:3       下载免费PDF全文
水果是我国最主要的植物源鲜活农产品之一,防腐保鲜和防腐保鲜剂对我国水果的生产、贮藏、运输与销售作用重大,是我国实现水果季节性生产和长期性供应的关键。本文从水果贮运中使用的主要防腐保鲜剂、我国允许使用的水果防腐保鲜剂、我国水果防腐保鲜剂最大残留限量以及水果防腐保鲜剂残留测定方法等4个方面,对我国水果防腐保鲜剂的使用与检测方法进行了综述,并指出水果防腐保鲜剂的合理使用和有效监管是保护消费者人体健康的关键。  相似文献   

17.
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   

18.
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   

19.
纳米农药及载体材料的增效机理研究现状   总被引:1,自引:0,他引:1  
农药的不科学使用容易引发一系列生态环境安全问题,严重制约着我国农业的可持续发展。纳米科技的长足进步推动了现代植物保护学科在交叉领域的不断深化和发展。以纳米科技为依托的药剂递送系统,可有效减少农药使用量,提升农药利用率,具有广阔的应用前景。该文结合最新的纳米农药研究进展,重点论述纳米农药的概念,介绍纳米农药的载体种类,分析纳米农药扩大靶标接触面积、促进植物内吸作用、提升叶面附着能力和调控药剂精准释放的增效机理,并对纳米农药的前沿应用进行展望。  相似文献   

20.
采用常规检测法、免疫斑点法、酶联免疫检测法和PCR检测法对柑橘溃疡病菌纯培养和柑橘叶片提取液进行平行测定。结果表明,对柑橘叶片提取液的检测,4种检测法检出的样品带菌率分别为11.12%、27.22%、18.69%、20.31%;对柑橘溃疡病菌纯培养的检测,4种方法检测结果一致。本实验同时比较了几种方法的灵敏度、特异性和稳定性,以及不同方法在各级检验检疫中的适应性。  相似文献   

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