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1.
萧氏松茎象幼虫龄数的估测   总被引:4,自引:0,他引:4  
室内和林间调查的结果表明 ,萧氏松茎象HylobitelusxiaoiZhang幼虫期为 5~ 7龄。该虫在林间以老熟幼虫的前 1龄幼虫 ,即以第 4~ 6龄幼虫越冬 ,其中以 5~ 6龄幼虫为主 ,4龄幼虫仅占少数  相似文献   

2.
根据萧氏松茎象产卵的生物学特性,用几种涂干剂涂刷湿地松,结果表明:用生石灰、硫磺、水配成的涂干剂防治效果达80%以上,绿色威雷则高达95%,其有效期均长达一年;用前者开展林间大面积防治,防效80%,防治平均成本0.106元.株-1。用乳胶漆把树干涂成不同颜色,结果表明:防治效果可达70%-95%,黑色、褐色的防效高于黄色和白色,萧氏松茎象对颜色的选择更趋向于偏暖的色彩。  相似文献   

3.
萧氏松茎象的早期寄主研究   总被引:11,自引:0,他引:11  
本文以调查的事实材料为基础,对萧氏松茎象的早期寄主进行了研究,说明该虫最先在马尾松树种上发生,而后逐渐蔓延到从国外引进的湿地松、火炬松和国外松上猖獗危害。 萧氏松茎象(HylobitelusxiaoiZhang)是江西省吉安地区 1988年发现的国外松新害虫。十多年来,该虫蔓延十分迅速,危害国外松特别严重。据1999年调查,江西省40余县(市)有分布.发生面积1万公顷以上,成为国外松的主要害虫。究竟此虫最初寄主是何树种,它为什么发展那么快呢?弄清这一问题十分重要,不仅对制订正确的防范措施,而且对研…  相似文献   

4.
采用聚集度指标法和回归分析法,对思茅松毛虫幼虫在林间的空间格局进行测定,并用刀切法对聚集度指标进行估计和检验,结果表明,思茅松毛虫幼虫在林间呈聚集分布,分布的基本成份为个体群.并计算了林间调查的理论抽样数,列出序贯抽样分析表。  相似文献   

5.
萧氏松茎象危害与松树松脂量关系研究初报   总被引:6,自引:1,他引:5  
萧氏松茎象HylobitelusxiaoiZhang是近年来暴发性松树害虫 ,主要危害 3种松树 :湿地松 (PinuselliottiiEngelm)、火炬松 (P .taeda)、马尾松 (P .massoniaanaLamb) ,其中以湿地松受害最为严重。为明确萧氏松茎象的危害与松脂流量的关系 ,作者对萧氏松茎象危害前后 3种松树 (湿地松、马尾松、火炬松 )松脂流量变化进行了研究。结果显示 ,在松树受害植株和未受害植株间松脂总流量间存在一定差异 ,其中以马尾松松脂流量变化最大 ,对受害株和未受害株松脂流量t-测验 ,差异达到显著水平 ;而湿地松和火炬松松脂总流量在受害植株和未受害植株间没有显著差异。对上述 3种松树松脂流量随时序动态变化的分析显示 ,松脂流量在 1年中以 5月到 6月之间为松脂流量高峰期 ,此后逐渐下降 ,到 3月中旬以后松脂流量又开始上升。就松脂流量时序动态而言 ,萧氏松茎象为害对马尾松松脂流量影响最大 ,对其它2个松树影响不明显。另外 ,不同松树树种在松脂流量及其时序动态上也存在一定差异 ,其中以马尾松脂流量较高。  相似文献   

6.
刚竹毒蛾幼虫空间分布型及其在实践中的应用   总被引:5,自引:1,他引:4  
本应用比较频次分布法,聚集度指标法和相关系数法,测定了刚竹毒蛾(Panatana phyllostachysae Chao)幼虫的空间分布型;同时用刀切法对其种群的平均拥挤度(m^*)进行估计。研究结果表明,其分布型属于负二项分布,其分布的基本成分为个体群,中分析并计算了林间调查的最适抽样数,列出幼虫序贯抽样分析表。  相似文献   

7.
竹小蜂幼虫空间分布型及抽样技术研究   总被引:6,自引:3,他引:3  
竹小蜂幼虫空间分布型属于负二项分布;聚集度各指标测定结果表明,幼虫是聚集分布;经测定M^*=6.2836 0.3028^ˉx,屑于聚集分布。并用刀切法和F偏离度检验法对M^*进行了估计和检验测定为聚集分布。中分析并计算了林间调查的理论抽样数和序贯抽样决策,为今后该虫林间调查与防治提供了科学的依据。  相似文献   

8.
外来树种对本地林业虫害的诱发作用   总被引:2,自引:0,他引:2  
白蜡窄吉丁、萧氏松茎象、光肩星天牛、黄斑星天牛、云斑天牛和桑天牛等林业害虫均为我国本地林业生态系统中的昆虫种类,在北美白蜡树、北美松树和北美黑杨派杨树等外来树种引入和大量栽培之前,一直没有形成严重的危害,以至于白蜡窄吉丁和萧氏松茎象都没有引起人们的关注。这些重要林业害虫在我国的发生都是伴随着敏感外来树种的引进和大量不合理的种植而逐渐严重起来的。本文对外来树种的引进与本地林业虫害的发生之间的关系进行了分析,提出了外来树种的不合理引进可能诱发本地林业新虫害的观点,并对其发生机理以及相应的研究和治理对策进行了讨论。  相似文献   

9.
黑角直缘跳甲幼虫空间分布型及抽样技术的研究   总被引:9,自引:0,他引:9  
通过运用二种回归方法和六种聚集度指标对黑角直缘跳甲幼虫的空间格局和抽样技术进行了研究。所有的指标表明黑角直缘跳甲幼虫在林间呈聚集分布,分布的基本成分是个体群,且个体间相互吸引。在空间分布型研究的基础上提出了理论抽样数和序贯抽样方案。通过不同抽样方式的精确度比较,表明对角线抽样方式最佳。  相似文献   

10.
《环境昆虫学报》2013,35(4):435-440
为摸清萧氏松茎象Hylobitelus xiaoi zhang受害松林的环境因子特征,应用林地环境因子常规观测方法进行观测,结果表明:8月份受害松林地面平均光照强度、地面温度、距地表20 cm高处温度、5 cm深处土壤温度、70 cm高处蒸发量分别为3748 lx、254℃、271℃、255℃、16 mm,分别比健康松林低948%、70%、46%、59%、273%,受害松林在距地表20 cm高处空气相对湿度为858%,比健康松林高71%。由实验得知,萧氏松茎象受害松林的光照强度、地面温度、空气温度、土壤温度、蒸发量均比健康松林低,空气相对湿度比健康松林高,距地表越近,这一差异就越明显。两类林分中的光照强度、空气温度、土壤温度、空气相对湿度4因子均存在明显差异,是影响萧氏松茎象发生的重要因素。  相似文献   

11.
玉米田斜纹夜蛾空间分布型及抽样技术   总被引:15,自引:0,他引:15  
对秋甜玉米田的斜纹夜蛾不同发生密度田块调查 ,取得了 7组样本资料 ,运用聚集度指标法、Iwao法和Taylor法等对其空间分布型进行测定检验 ,结果表明斜纹夜蛾幼虫呈聚集分布 ,其聚集原因经Blackith种群聚集均数测定 ,当m <3 .2 60 4时 ,其聚集是由于某些环境如气侯、土壤湿度、植株生长状况等所致 ;当m >3 .2 60 4时 ,其聚集是由于害虫本身的群集行为与环境条件综合影响所致。在此基础上 ,通过几种抽样方式比较以五点式为最佳 ,并提出了最佳理论抽样数和最佳序贯抽样模型 :N =1 D2 (3 .8981 m +0 .75 0 3 ) ,To(n) =0 .5n± 2 .865n。  相似文献   

12.
The purpose of this research was to quantify the spatial pattern and develop a sampling program for larvae of Lobesia botrana Denis and Schiffermüller (Lepidoptera: Tortricidae), an important vineyard pest in northern Greece. Taylor's power law and Iwao's patchiness regression were used to model the relationship between the mean and the variance of larval counts. Analysis of covariance was carried out, separately for infestation and injury, with combined second and third generation data, for vine and half-vine sample units. Common regression coefficients were estimated to permit use of the sampling plan over a wide range of conditions. Optimum sample sizes for infestation and injury, at three levels of precision, were developed. An investigation of a multistage sampling plan with a nested analysis of variance showed that if the goal of sampling is focusing on larval infestation, three grape clusters should be sampled in a half-vine; if the goal of sampling is focusing on injury, then two grape clusters per half-vine are recommended.  相似文献   

13.
临泽盐渍化草地空间格局的可塑性面积单元问题   总被引:1,自引:0,他引:1  
李广  侯扶江  黄高宝 《生态学报》2008,28(1):154-161
通过对临泽盐渍化草地群落取样资料的分析表明,草地空间格局的分布对样地尺度变化和划区方案选择均存在敏感性.样地面积在12500m2以下时,尺度增聚效应表现非常明显.在同一取样面积单元下不同的划区方案对草地的空间分布都有一定的影响,但随着取样面积的增大,区划方案的影响也是减少的.因此在研究草地空间分布格局时,要力求寻找一个最佳的区划方案和取样尺度,使得面积单元内的差异最小是非常有必要的.  相似文献   

14.
眉斑并脊天牛幼虫龄数及各龄特征   总被引:5,自引:1,他引:4  
赖开平  陆温  刘德星  骆峥嵘  高鹏宇 《昆虫知识》2008,45(1):138-140,F0002
测定头壳宽度室内观察结果表明,眉斑并脊天牛Glenea cantor(Fabricius)幼虫有4龄。1~4龄幼虫的头壳宽度分别为(0.66±0.20),(1.45±0.20),(2.22±0.23),(3.26±0.29)mm。其龄数(Y)与幼虫头壳宽(X)度符合关系式Y=0.2975+1.1606X。在25℃条件下,1~4龄幼虫的平均龄期分别为(5.25±0.60),(4.94±0.58),(5.98±0.63)d和(22.92±1.28)d,整个幼虫期为(39.09±2.14)d。还对眉斑并脊天牛各龄幼虫的形态特征作了描述。  相似文献   

15.
红棕象甲幼虫空间格局研究   总被引:1,自引:0,他引:1  
【背景】红棕象甲是外来危险I生有害生物,近十年来在我国南方严重危害棕榈科植物。[方法】为了确定其调查抽样方法、准确获得虫情,应用聚集度指标法和回归模型分析法等,对红棕象甲幼虫的空间格局进行了研究。【结果】在lwao模型中,α=0.4208〉0,β=1.5133〉1,这说明了红棕象甲幼虫的种群空间格局的分布图式为聚集型;用马占山重新解释的Taylor幂法则分析表明,红棕象甲幼虫的空间格局归属于聚集型,个体之间相互吸引。【结论与意义】红棕象甲幼虫在林内呈聚集型分布,分布的基本成分为个体群;运用1wao法确定了林间最适理论抽样数和序贯抽样模型,为该虫的监测与防治提供了依据。  相似文献   

16.
The spatial distribution of Culicoides impunctatus Goetghebuer (Diptera: Ceratopogonidae) larvae was sampled at a site in western Scotland, and geostatistical analyses were used to quantify spatial dependencies. Nested sampling and analysis indicated that most of the spatial variance occurred within distances of 160-640 cm, levelling off at distances >640 cm. Semivariograms for transformed data from three 100 m x 100 m grids showed similar, isotropic patterns for larval counts, soil organic content, soil water content and the distribution of Juncus spp. rushes, with the variance increasing with separation distance. High levels of significance were associated with power models used to describe the semivariograms, which was indicative of the absence of a plateau (or 'sill') in the respective data. Correlation analysis of transformed data revealed significantly positive relationships between larval counts and soil pH, soil percentage organic content, soil percentage water content and also the distribution of Sphagnum spp., Juncus spp. and Myrica gale. There were also significantly negative relationships between larval counts and the distribution of Pteridium aquilinum and all mosses other than Sphagnum spp. The results suggest a far more structured and predictable pattern of C. impunctatus larval sites than previous studies and are discussed in relation to their application in localized Culicoides control and to studies of the mechanisms determining the spatial distribution of C. impunctatus larvae.  相似文献   

17.
刺槐叶瘿蚊越冬幼虫空间格局及抽样调查技术   总被引:1,自引:1,他引:0  
本文采用聚集指标法分析了刺槐叶瘿蚊Obolodiplosis robiniae(Haldemann)越冬幼虫的空间分布格局,结果表明:刺槐叶瘿蚊越冬幼虫在林间呈聚集分布;其聚集的原因与刺槐叶瘿蚊自身的行为习性有关或由刺槐叶瘿蚊本身与环境的异质性共同作用所造成。采用"z"字型、平行线、棋盘式、大五点、对角线5种抽样方法估计林间刺槐叶瘿蚊越冬幼虫虫口密度,确定对角线法调查15样方为最佳抽样方法。对土壤不同深度土层中越冬幼虫数量调查,明确最适取样深度为3cm。同时利用Iwao回归建立了理论抽样数量模型:n=t2/D2(1.1957/x珋+0.8905)。利用过筛手检和过筛水漂2种方法检数土中幼虫,对检出刺槐叶瘿蚊越冬幼虫虫量及检虫时间进行了对比分析,结果表明过筛水漂法检虫较为可取。  相似文献   

18.
We investigated receptive field properties of cat retinal ganglion cells with visual stimuli which were sinusoidal spatial gratings amplitude modulated in time by a sum of sinusoids. Neural responses were analyzed into the Fourier components at the input frequencies and the components at sum and difference frequencies. The first-order frequency response of X cells had a marked spatial phase and spatial frequency dependence which could be explained in terms of linear interactions between center and surround mechanisms in the receptive field. The second-order frequency response of X cells was much smaller than the first-order frequency response at all spatial frequencies. The spatial phase and spatial frequency dependence of the first-order frequency response in Y cells in some ways resembled that of X cells. However, the Y first-order response declined to zero at a much lower spatial frequency than in X cells. Furthermore, the second-order frequency response was larger in Y cells; the second-order frequency components became the dominant part of the response for patterns of high spatial frequency. This implies that the receptive field center and surround mechanisms are physiologically quite different in Y cells from those in X cells, and that the Y cells also receive excitatory drive from an additional nonlinear receptive field mechanism.  相似文献   

19.
20.
Doguwa and Upton (1988) propose edge corrections for the mean and variance of the average distance X , between a sampling point and the nearest object in a spatial point pattern for the case of a regular grid of sampling points. However, their edge corrections are not applicable to circular sampling windows. This paper extends the range of application of X , by providing its revised mean and variance for use with circular regions.  相似文献   

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