拟澳洲赤眼蜂对小菜蛾卵的适应能力

本文比较经米蛾卵繁殖的拟澳洲赤眼蜂在小菜蛾卵和米蛾卵上的产卵差别，结果为：不喂蜜糖水，拟澳洲赤眼蜂寿命短，不到一天，可在小菜蛾卵上产卵的雌蜂比 只有４５．４５％，比可在米蛾卵上产卵的雌蜂比例低得多，可产卵雌蜂的平均产卵量亦是在小菜蛾卵上的低，喂以蜜糖水，拟澳洲赤眼寿命得以延长，平均寿命达１２天以上，可在小菜蛾卵上产卵的雌蜂比例为９６．１３％，与可在米蛾卵上产卵的雌蜂比例相当，并且在两种寄主卵上可产     

1.0%苦参碱可溶液剂的配方及润湿和喷雾性能

为开发出适宜于飞防的苦参碱可溶液剂，并明确其润湿性能及喷雾性能，本研究采用单因素试验筛选苦参碱可溶液剂的润湿分散剂种类及用量，测试了各配方的热贮和低温稳定性，利用光学接触角测量仪测试制剂的表面张力和接触角，利用水敏纸测试苦参碱可溶液剂在无人机喷雾时的雾滴密度及覆盖率，以此评价药剂的润湿性和喷雾性能。结果显示：BY-125为适宜于苦参碱可溶液剂的润湿剂，且当BY-125用量为1%～5%时，制剂具有较好的稳定性；随着BY-125用量升高，苦参碱可溶液剂的静态表面张力（SST）和动态接触角（DCA）逐渐下降。向稀释液中添加1.5%倍达通后，SST和DCA均分别降低48.78%～52.39%和56.59%～62.81%；桶混1.5%倍达通后，1%苦参碱可溶液剂对燕麦蚜虫麦二叉蚜的防效、雾滴密度和覆盖率较未桶混倍达通时均有显著提高。研究表明，BY-125可用于配制苦参碱可溶液剂，其最佳用量为1%，桶混1.5%倍达通可显著提高苦参碱可溶液剂的润湿性能和沉积性能，本文优化了苦参碱可溶液剂在飞防中的喷雾性能和防治效果。     

瓜实蝇在云南生物学习性研究初报

瓜实蝇是水果和瓜类蔬菜的主要害虫，在昆明1年可发生5代，河口可发生7代，瑞丽可发生8代，世代重叠，全年有活动，以老熟幼虫，蛹入土越冬，本文对瓜实蝇不同虫态在不同温度下的历期和习性做了记录和描述。     

民族村寨农民旅游可持续增收的影响机制及其因素差异性研究——以瑶壮侗苗民族村寨为例

旅游是民族村寨农民实现可持续增收的关键途径，影响农民旅游可持续增收的因素众多，但民族村寨农民旅游可持续增收的影响机制却鲜有学者基于科学的理论框架进行系统化研究，更难以将多种内源性和外源性因素置于同一模型中进行研究。文章以可持续生计理论为基础，以DFID-SLA为理论框架，以广西桂林金坑大寨(瑶)、平安壮寨(壮),贵州黔东南肇兴侗寨(侗)、西江苗寨(苗)为案例地的540份问卷调查和63份访谈为数据资料，测度影响旅游可持续增收结果的因素，揭示旅游可持续增收机制，从农户尺度分析农民旅游可持续增收结果影响因素的差异。研究发现：1)农民生计资本、制度环境感知和生计策略均对旅游可持续增收结果有正向效应，制度环境感知作为外源因素对生计资本、生计策略和旅游可持续增收结果有显著正向效应，生计资本是影响旅游可持续增收的最主要因素。2)生计策略多元性在农民生计资本到旅游可持续增收结果这条路径上起到部分中介作用，但是不同村寨的传递效应存在差异。3)7种类型农户在农民生计资本、制度环境感知和生计策略存在差异显著，且在生计资本要素上差异最为显著。据此，研究构建的民族村寨农民旅游可持续增收机制框架得以检验，为民族村...     

绿洲外围植被防护生态效益的研究

ｋ－ε紊流数学模型是模拟风通过绿洲外围植被区流场细节的有效手段，由此可找出风流通过植被区，在顺风方向及随植被盖度变化的递变规律，并可定量地反映绿洲外围植被降低风速、降低进入绿洲沙流量的生态效益。试验表明，顺风方向２ｋｍ的植被盖度由０增至１５％－２０％，可降低风速３７％－４０％；增至３５％－４０％，可降低４８％左右；增至５５％，可降低５４％左右。植被盖度由０％增至１５％，３５％，５０％，在地面上以０     

微孢子虫饵剂的不同配方对新疆草原蝗虫的防治效果

在新疆用微孢子虫对３种草原蝗虫进行室内感病性试验，结果不同种蝗虫的感病率差异很大，红胫戟纹蝗的感病率高达８３．５％，而意大利蝗和西伯利亚蝗仅分别为３４．５％和１７．７％。用飞机在草原喷洒，微孢子虫饵剂每１００克加５０％马拉硫磷４ｍｌ和１０ｍｌ，对意大利蝗和红胫戟纹蝗虫口减退率可增加到７６．７％和７６．０％，明显高于单用微孢子虫饵剂的杀虫效果。作者认为在一般蝗虫发生年份，单用微孢子虫饵剂可压低虫口到防治指标（１０头／ｍ２）以下，蝗虫发生量大的年份，采用加微量农药的微孢子虫饵剂，既可提高防效，也可比单用农药减少对环境的副作用     

农药对靶喷撒技术研究初报

通过稻，麦，棉，茶，黄瓜，油菜等作物上一系列农药喷撒试验和生产性示范表明，采用对靶喷撒技术和相应的喷撒手段，可显著提高农药在有效靶区的沉积率，农药用量可％－５０％，喷雾用水量可降低９５％以上。农药对靶喷撒技术是根据病菌或害虫在作物上的分布，作物的田间群体结构以及农药雾滴在株冠中的行为的综合研究所提出的化学防治法的一项基本原理和基本技术。     

农药塑料瓶的回收有待规范

近年来，随着国内农药厂家的增多和农民用药量的增大，农药厂家之间的竞争越来越激烈，由于在出售农药时，农民很难辨别其内在质量，因此农药瓶便成了厂家之间的竞争目标。从农药经销点中可看到，各种用聚乙烯、聚丙烯等加工成的大大小小透明和不透明的塑料瓶摆满了柜台，农民也可根据用药量的多少来选择不同含量的农药瓶，这本是一件好事，可导致的结果是，在农村的田野里、水塘边、     

荠菜的无公害栽培技术

荠菜为十字花科一年生草本植物，在我国各地均有分布。野生荠菜多生于沟边、田埂、路旁及荒地中。其嫩株可凉拌、炒食、做馅等，味道清香鲜美。茎、叶、果实可入约，有止血、明日等功效。荠菜生长期短，耐低温而且适应性强，可很好地进行人工栽培。     

绿黄隆及其复配剂对稻麦产量的影响

在我市马肝土、黄泥土、黄沙土三种代表土壤类型中，使用绿黄隆及其复配剂对小麦的增产效果明显，但对9－92水稻产量的影响亦非常明显。在推荐剂量下，在马肝土上春用化除可致使后茬9－92水稻减产6．78％，在黄泥土、黄沙土上冬用化除可致使9－92水稻减产10．47％和15．32％。黄沙土、黄泥土、马肝土上种植9－92水稻，绿黄隆的亩临界用量分别为：0．11～0．22g、0．37g、0.66g。水稻基肥中亩用麦秸200kg直接还田，可减少损失4个百分点，减轻危害程度18．61％～31.35％。因此，我市沿江及洮塥农区应不用绿黄隆及复配剂，丘陵农区可推广使用双黄隆类复配剂，并推行麦秸直接还田。     

Nei's gene diversity and the index of average differences are identical measures of diversity within populations

It has been established that Nei's measure of the average genetic diversity per locus, H _S , and the measure of average differences between isolates with respect to simple mismatch dissimilarity, are identical measures of diversity within populations. The Müller index of diversity can be considered as the correction of Nei's measure for small samples.     

加拿大一枝黄花的防控措施

加拿大一枝黄花人工拔除需与春季化除结合起来配套实施。耕翻复种是一项经济有效的防除措施,可有效控制加拿大一枝黄花再生。草甘膦＋磺酰脲类除草剂在加拿大一枝黄花生长期内使用,对地上部分和地下根状茎都有很好的杀伤效果,但需注意的是,这类除草剂仅限在非耕地使用。南京农业大学杂草研究室研制的NJW001抑制剂能明显抑制加拿大一枝黄花花序的伸展和花蕾的开放,同时对株高也有明显的抑制作用。     

Measure of multilocus correlation as a new parameter for study of plant pathogen populations

ABSTRACT The measure of multilocus correlation for diallelic loci was developed to augment use of other diversity indices in the study of multilocus structure of populations. This measure provides information not revealed by other parameters for measuring multilocus association and linkage disequilibrium among pairs of loci. Relationships between the measures of multilocus correlation and association and all commonly used indices for diversity within populations are also described. A number of hypothetical examples demonstrate that the measure of multilocus correlation describes unique aspects of multilocus structure of populations compared with the measure of multilocus association and phi coefficient of association. The measure of multilocus correlation can be used for analysis of independence of differentiating characters for a given population-the necessary condition of valid applications of the bootstrap method across differentials. Comparisons of the measures of multilocus correlation and association with the measures of diversity within population show that they reveal different aspects of population structure. As an adjunct to standard diversity indices, the measure of multilocus correlation may reveal subtle differences in diversity within populations even if the standard index fails to distinguish between the populations. A new measure of population uniformity also was developed to characterize another aspect of diversity within populations not detected by standard indices.     

A quantitative genetic examination of non‐target‐site resistance applied to Avena species

Quantitative genetics tools can be used to assess whether using herbicides at low doses drive selection on standing genetic variation in populations leading to non‐target‐site resistance (NTSR). These tools are particularly important for estimating the number of genes involved and the potential speed of evolution. A short cut to answering questions about the evolution of NTSR may be to measure heritability. The heritability index (H) provides a measure of the potential to develop NTSR and can be simply calculated from classical dose–response experiments. This measure and the associated experimental designs are discussed with two applied examples on Avena spp. (A. fatua and A. sterilis). In these examples, H values ranged from 0.24 to 0.73, which means that selection for NTSR is highly probable in cases with high H value. We suggest that structuring plants into genetic groups (e.g. families or populations) can contribute to our understanding of the evolutionary potential of populations and plant species to evolve resistance, without increasing experimental cost and time.     

陕北—黄土区生态户的生态建设是实现黄土高原生态恢复的重要步骤——党家山生态农户考察的启发

生态户是构成生态环境的最小单元,它既是一切生态建设措施的落脚点,也是促使陕北农民走出贫困、实现小康的奠基石。解决黄土高原的问题最为根本的是保护和合理利用水资源,通过生态户的建设,整合有关水土保持措施,使其长期稳定地发挥生态效益,最终促进陕北多沙粗沙区生态环境的根本性好转。必须实施重点突破战略,采取典型引路的方式,层层落实、步步为营,一点一点地治理,积少成多,绝不反复,最后实现全面好转。     

陕北-黄土区生态户的生态建设是实现黄土高原生态恢复的重要步骤——党家山生态农户考察的启发

生态户是构成生态环境的最小单元，它既是一切生态建设措施的落脚点，也是促使陕北农民走出贫困、实现小康的奠基石。解决黄土高原的问题最为根本的是保护和合理利用水资源，通过生态户的建设，整合有关水土保持措施，使其长期稳定地发挥生态效益，最终促进陕北多沙粗沙区生态环境的根本性好转。必须实施重点突破战略，采取典型引路的方式，层层落实、步步为营，一点一点地治理，积少成多，绝不反复，最后实现全面好转。     

A Quantitative Assay Using Mycelial Fragments to Assess Virulence of Mycosphaerella fijiensis

ABSTRACT We describe a method to evaluate the virulence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease (BLSD) of banana and plantain. The method is based on the delivery of weighed slurries of fragmented mycelia by camel's hair brush to 5-by-5-cm areas on the abaxial surface of banana leaf blades. Reliable BLSD development was attained in an environmental growth chamber with stringent lighting and humidity controls. By localizing inoculum onto small areas of large leaves, we achieved a dramatic increase in the number of strains that can be tested on each leaf and plant, which is critical for comparing the virulence of numerous strains concurrently. Image analysis software was used to measure the percentage of each inoculated leaf section showing BLSD symptoms over time. We demonstrated that the level of disease of four isolates was correlated with the weight of the mycelium applied and relatively insensitive to the degree of fragmentation of hyphae. This is the first report demonstrating that weighed mycelial inoculum, combined with image analysis software to measure disease severity, can be used to quantitatively assess the virulence of M. fijiensis under rigorously controlled environmental conditions.     

An improved particle tracking velocimetry(PTV) technique to evaluate the velocity field of saltating particles

Velocity is a key parameter characterizing the movement of saltating particles. High-speed photography is an efficient method to record the velocity. But, manually determining the relevant information from these photographs is quite laborious. However, particle tracking velocimetry(PTV) can be used to measure the instantaneous velocity in fluids using tracer particles. The tracer particles have three basic features in fluids: similar movement patterns within a small region, a uniform particle distribution, and high particle density. Unfortunately, the saltation of sand particles in air is a stochastic process, and PTV has not yet been able to accurately determine the velocity field in a cloud of blowing sand. The aim of the present study was to develop an improved PTV technique to measure the downwind(horizontal) and vertical velocities of saltating sand. To demonstrate the feasibility of this new technique, we used it to investigate two-dimensional saltation of particles above a loose sand surface in a wind tunnel. We analyzed the properties of the saltating particles, including the probability distribution of particle velocity, variations in the mean velocity as a function of height, and particle turbulence. By automating much of the analysis, the improved PTV method can satisfy the requirement for a large sample size and can measure the velocity field of blowing sand more accurately than previously-used techniques. The results shed new light on the complicated mechanisms involved in sand saltation.     

A System to Measure Viscosities of Spray Mixtures at High Shear Rates

The viscosity of spray mixtures can greatly influence the sizes of spray droplets produced by atomizers. However, no low-cost system has been available to measure the viscosity at the high shear rates that are typical of pesticide mixtures passing through orifices of nozzles at pressures commonly used in agricultural spraying. An inexpensive system was developed to measure viscosity at shear rates up to 200000 s⁻¹ for both Newtonian and non-Newtonian liquids. Viscosity measurements of Newtonian liquids with viscosities ranging from 0·87 to 9·1 mPa s indicated that the measured viscosity was within 5% of the actual value at various high shear rates up to 200000 s⁻¹. As shear rate was increased, the viscosities of mixtures of water with drift control agents ‘Nalco-Trol,’ ‘Target’ and an experimental formulation decreased remained about the same, and increased respectively.     

液流—株间微型蒸渗仪法测定新疆杨蒸发蒸腾量适用性分析

采用液流—株间微型蒸渗仪法测定人工种植环境下新疆杨蒸发蒸腾量,并对此方法的适用性进行了分析。结果表明：在生长季5—10月,新疆杨蒸腾量具有明显的季节变化规律,总蒸发蒸腾量为508.26 mm,蒸发量、蒸腾量所占比率分别为37.1%和62.9%;树干液流速率与叶片蒸腾速率变化表现出较好的一致性,热脉冲法能够用于新疆杨蒸腾测定;液流—株间微型蒸渗仪法和水量平衡法测算结果的相对误差在±15%之内,液流—株间微型蒸渗仪法能够适用于新疆杨蒸发蒸腾量测定。