番茄潜叶蛾幼虫和卵在新疆大棚番茄的空间分布型及理论抽样数

【目的】明确新疆新发外来入侵生物番茄潜叶蛾幼虫和卵在不同种群密度下的垂直分布、空间分布型和理论抽样数,探索田间易观察的危害症状和幼虫密度的关系,为田间取样和调查提供理论指导。【方法】在察布查尔县连续调查3个大棚同一品种京番502杂交一代上的番茄潜叶蛾的不同种群密度,利用聚集度指标及Iwao回归分析,计算并分析了番茄潜叶蛾卵和幼虫在不同种群密度下的空间分布型、垂直分布和理论抽样数,分析危害叶片数、虫道长度和虫道数与幼虫密度的动态关系。【结果】计算并统计番茄潜叶蛾幼虫和卵的空间分布聚集度指标的均值m、扩散系数C、扩散型指数I、负二项分布值K、平均拥挤度m~*、聚块指数m~*/m、扩散指数CA和种群聚集均数λ。番茄潜叶蛾卵主要集中在上部,占比43.9%～100%。幼虫主要集中在下部,占比53.3%～100%。番茄潜叶蛾幼虫数与虫道数、虫道长度或为害叶片数的比值随为害加剧呈动态变化。番茄潜叶蛾幼虫和卵Iwao直线回归方程拟合公式为m~*=1.9114+1.2055m (R~2=0.9703)和m~*=0.0536+1.4147m (R~2=0.9014)。根据空间分布型参数,在D=0.1、0. 2和0. 3时,幼虫的理论抽样数模型分别为n=1118. 4/x+78. 9、n=279. 6/x+19.7、n=124.3/x+8.8,卵的理论抽样数模型分别为n=404.8/x+159.3、n=101.2/x+39.8、n=45.0/x+17.7,该模型适用于不同虫口密度下的田间抽样。【结论】在京番502杂交一代上,番茄潜叶蛾幼虫为m=0.6头·株~(-1)以上,卵在达到密度最大值前,均呈聚集性分布。番茄潜叶蛾成虫偏好在幼嫩的叶片产卵,随植株被害加剧该偏好略有减弱。当番茄潜叶蛾幼虫的虫口密度为10和30头·株~(-1)时,建议分别取样50和30株;当卵量为10和30粒·株~(-1)时,分别取样50和45株。     

桃树上扁刺蛾幼虫空间分布型的参数特征及其应用

通过测定桃树上扁剌蛾幼虫的空间参数m、K、α、β、b值,导出了桃树上扁刺蛾幼虫属聚集公布,分析了引起聚集分布的原因,同时根据Iwao、Kuno法,分别制订了幼虫不同密度、不同结果枝未被害率下的几种理论抽样模型,根据Gerrard法制订了不同结果枝被害率下虫量密度的简易估值模型,经检验效果较好。     

稻水象甲卵的空间分布型及抽样技术研究

本文利用Taylor幂法则和Iwao回归法对稻水象甲LissorhoptrusoryzophilusKuschel卵的空间分布型进行了测定 ,结果表明稻水象甲卵在田间呈聚集分布 ,且符合负二项分布 ,k值为 0 4 796。其种群聚集主要是由环境因子引起的。应用Iwao的抽样模型建立了稻水象甲卵的田间理论抽样数公式 :N =1D2 1 784 6M + 0 2 4 2 5 。并根据Gerrard的零频率模型建立了估计该种群平均密度的零频率模型 :X =1 5 787( -lnP0 ) 1 0 62 5。     

两色绿刺蛾幼虫空间分布型

应用聚集度指标法、回归分析法、零频率方法对两色绿刺蛾幼虫在毛竹林间的分布型进行测定。结果表明,两色绿刺蛾幼虫在竹林中呈聚集分布,分布的基本成分为个体群。用零频率方法分析得,两色绿刺蛾幼虫种群类型为聚集度零频率制约型,并确定了林间调查的理论抽样数和简单序贯抽样分析表。     

苜蓿籽蜂幼虫空间分布型及抽样技术的研究

应用多个聚集度指标和Iwao、Taylor回归分析方法,对苜蓿籽蜂Bruchophagus roddi幼虫的空间分布型进行研究。结果表明其空间分布型为负二项分布,个体间相互排斥,其基本成分的空间分布格局为聚集分布,其聚集是由昆虫行为或环境条件引起的,聚集强度随着种群密度的升高而增加。应用 Iwao抽样模型建立了籽蜂幼虫的田间理论抽样数公式：N=(0.5833/m+2.3370)/D∧2。      

柠条重要害虫四线奇尺蛾天津亚种幼虫的空间分布研究

四线奇尺蛾天津亚种是近几年新发现的危害柠条的重要害虫,研究四线奇尺蛾种群的空间格局和抽样技术,可为该害虫的危害调查与防治提供理论依据。本文应用6个聚集指标和Taylor幂法则及Iwao的m~*-m回归分析法,对四线奇尺蛾天津亚种幼虫的空间分布型和抽样技术进行了研究,并做了影响因素分析。结果表明:四线奇尺蛾天津亚种幼虫在6个样地均呈聚集分布,分布的基本成分是个体群,通过分布型参数,采用Iwao法计算出了在不同精度下幼虫抽样数公式和序贯抽样模型,该模型可为四线奇尺蛾天津亚种的预测预报及防治提供理论依据。     

斑膜合垫盲蝽若虫在国槐上的空间分布型及抽样技术

斑膜合垫盲蝽Orthotylus(O.)sophorae Josifov是近年来临夏地区国槐Sophora japonica Linnaeus上严重发生的害虫之一。应用6种分布型指数法分析判定了斑膜合垫盲蝽若虫在国槐上的空间分布型,利用Taylor幂法则和Iwao回归方程分析聚集原因,结果表明,斑膜合垫盲蝽若虫在国槐上呈聚集分布,公共k c值为0.6169,且符合负二项分布;其种群聚集是由某些环境作用引起的。在此基础上,采用Iwao的方法确定了斑膜合垫盲蝽若虫的田间最适抽样数和序贯抽样表;并根据Gerrard的零频率模型建立了估计该种群平均密度的零频率公式:x=1.7457(-lnP0)1.1119。     

砂生槐种子蜂危害空间格局及理论抽样研究

应用6种聚集度指标、Taylor和Iwao回归分析法对砂生槐种子蜂幼虫的空间分布格局进行了分析,得出砂生槐种子蜂幼虫的空间分布型为聚集分布,田间调查抽样方法为分行取样法,并得出田间幼虫不同密度时的理论抽样数。     

陕北烟田多异瓢虫空间分布型与抽样技术研究

根据1995年烟田多异瓢虫Hippodamiavariegats（Goeze）调查,计算了6种分布型指数,以及频次拟合优度检验,结果表明：该虫幼虫、蛹在陕北烟田里聚集分布,其聚集强度随种群密度增加而降低,聚集原因是环境差异;卵块分布同时具有聚集和随机的趋势,成虫为随机分布。同时建立了各虫态的理论抽样量公式,估测种群密度公式。     

向日葵螟幼虫的空间分布型及抽样技术

欧洲向日葵螟Homoeosoma nebulellum Denis et Schiffermüller是向日葵上的主要害虫,本文利用6种聚集指标对向日葵螟幼虫的空间分布型进行了测定,结果表明其呈现聚集分布。样本平均数(m)与方差(S2)的对数值的关系式为:lgS2=lg0.2130+0.5639lgm,显示向日葵螟幼虫的空间分布随密度的升高而趋向均匀分布。Iwao的m*-m回归方程为:m*=8.1177+0.1447m,显示该虫在田间分布的基本成分是个体群,个体间相互吸引,个体群的空间分布型为均匀分布。对聚集原因进行分析,得出λ<2,表明向日葵螟幼虫的聚集是由于环境作用所引起的。用Iwao的理论抽样数模型计算出向日葵螟幼虫的理论抽样数模型为:D=0.1时,n=911.77/m-85.53,D=0.2时,n=227.94/m-21.38。采用m*-m关系的序贯抽样模型制定出食葵田间的序贯抽样模型为:T1(n),T0(n)=7.40n±4.54n,油葵田间的序贯抽样模型为:T1(n),T0(n)=10.05n±2.29n。     

绿僵菌药后草原蝗虫种群空间分布型研究

综合多个聚集度指标对绿僵菌药后田间蝗虫和僵虫的空间分布型进行了研究。结果表明：施药后不同时间随蝗虫种群密度的减小,处理区残虫的分布型呈现聚集随机交错变动,僵虫的空间分布型为聚集分布。采用Taylor幂法则和改进的Iwao模型分析表明,整个调查时段处理区残虫、僵虫的空间分布均为聚集分布。推测认为,药后蝗虫点片状死亡,部分地片相对密度较高,残虫分布型趋向聚集; 自然消除作用使僵虫密度很低,低密度下取样产生大量空样本,僵虫的分布型产生聚集假象。     

Spatial distribution on pasture of infective larvae of the gastro-intestinal nematode parasites of sheep

The horizontal distributions of infective larvae on pasture grazed by sheep have been investigated. Using Taylor's Power Law it was found that larvae had a more aggregated distribution in September than August, the Law index of aggregation being 1.97 and 1.89 for the 2 months, respectively. However, at each time the degree of aggregation remained fairly constant for a range of spacings between points from 5 to 30 m. These results suggest that Taylor's Power Law could be used as a basis for devising an efficient pasture sampling strategy. More data are required, however, to determine the extent to which aggregation of the larvae varies with time of the year.     

Spatial distribution of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) larvae in three scales.

The spatial distribution of larvae of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), the citrus leaf miner, in leaves, shoots, and tree crowns of Montenegrina tangerine (Citrus deliciosa Tenore) and Murcott tangor (Citrus sinensis L. Osbeck x Citrus reticulata Blanco) was determined. Fortnightly samplings from July/2001 to June/2003, in orchards located in Montenegro (29 degrees 68' S and 51 degrees 46' W), RS, Brazil, were carried out. At each sampling occasion eighth shoots randomly selected were collected. The spatial distribution pattern of P. citrella larvae between tree crowns and in the shoots was aggregated in most sampling occasions in both citrus species. Nevertheless, on the leaves, this pattern followed a random distribution, as indicated by the indices I, Idelta and k parameter.     

玉米田斜纹夜蛾空间分布型及抽样技术

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。     

Spatial dynamics of lepidopterous pests on Zea mays (L.) and Pennisetum purpureum (Moench) in the forest zone of Cameroon and their implications for sampling schemes

The most common lepidopterous borers attacking maize and/or the wild host Pennisetum purpureum in the forest zone of Cameroon are the noctuids Busseola fusca (Fuller), Sesamia calamistis (Hampson) and Poeonoma serrata (Hampson), the pyralids Eldana saccharina (Walker) and Mussidia nigrivenella (Ragonot), and Cryptophlebia leucotreta (Tortricidae). The within-plant distribution on maize and elephant grass was studied for the predominant species B. fusca , and on maize only for E. saccharina to determine the basic sampling unit. On both plant species, B. fusca showed a strong oviposition preference for young plant parts. By contrast, E. saccharina larvae and pupae on maize were only found on older plant parts indicating that it does not oviposit on young plants. No part of the plant strata appeared to be a stable sampling unit and it is recommended to carry out whole plant or whole tiller sampling for maize and grass, respectively. For the development of sampling plans, dispersion was described for all species using Taylor's power law and a non-linear model which gives the relationship between the proportion of infested plants [ P ( I )] and mean density ( m ). Busseola fusca egg batches as well as diapausing larvae and pupae on maize showed a random distribution whereas all the other cases were aggregated, with B. fusca egg batches on elephant grass exhibiting the lowest and M. nigrivenella on maize the highest aggregation. Optimal sample size/mean density curves were developed for groups of insects with low and high aggregation.     

Distribution and feeding of larval Chironomidae in a gravel-pit lake

SUMMARY. Replicated benthic samples were collected from a wet gravel-pit in the English Midlands at fortnightly intervals during 1978. The aggregation patterns of the four most numerous genera, Chironomus, Polypedilum, Procladius and Tanypus , were analysed by fitting the means and variances of replicated sampling units to Taylor's power law and Iwao's plot of mean crowding against mean density. Chironomus larvae were not aggregated; all other genera showed an increased aggregation with density. The Iwao plots indicated that Tanypus larvae tended to be aggregated at low as well as high densities. Gut contents were analysed in larvae of the above genera and also in Cryptochironomus larvae, to investigate the relationship between dispersion pattern and feeding. Chironomus and Polypedilum larvae fed mainly on detritus, Tanypus on algae, Procladius on algae and crustacea and Cryptochironomus on oligochaetes. The extent of overlap in feeding niche was measured by Levins' index and shown to be low in all except the pair feeding upon detritus. Differences in the feeding niche may partly account for the dispersion patterns of the genera investigated.     

柳厚壁叶蜂幼虫空间格局及抽样技术

应用Taylor的幂法则、Iwao m^*-m回归分析法及6个聚集指标,对柳厚壁叶蜂幼虫空间分布型进行了研究,并进行了影响因素分析.结果表明,该幼虫在柳树的枝条和叶片两个空间阶元都属于聚集分布,分布的基本成分是个体群,其聚集性随密度的增大而增加.在枝条上,聚集的原因是由柳厚壁叶蜂成虫集中产卵的习性与枝条上叶片空间位点共同影响所致;在叶片上,当m＜2.37时,其聚集原因与春季柳树新叶空间位置有关,当m＞2.37时,虫瘿聚集除与春季新叶空间位置有关外,还与柳厚壁叶蜂成虫羽化和在叶片上集中产卵的习性有关.运用Iwao m^*-m回归中的两个参数α和β值,确定了在不同精度下的理论抽样数及序贯抽样数.     

The effect of pyrethroid lambdacyhalothrin applications on the spatial distribution of phytophagous and predatory mites in apple orchards

The spatial distribution of three phytophagous mites,Panonychus ulmi (Koch),Tetranychus urticae Koch andAculus schlechtendali (Nalepa), and two predacious mites,Zetzellia mali (Ewing) andAmblyseius fallacis (Garman), and the effect of pyrethroid lambdacyhalothrin applications on mite spatial dispersion were investigated over a 3-year period in an apple orchard in Ontario. The index of dispersion and the slope of Taylor's power law were used to evaluate dispersion patterns of mites. Panonychus ulmi showed that between-tree spatial variation decreased with an increase of population densities, whereas between-leaf variation increased with population densities. With all other four species it appeared that between-tree variation is much greater than between-leaf variation at all field population density levels. The values ofb by Taylor's power law suggested that all five species of mites are aggregated, but that in generalP. ulmi andT. urticae (b=1.427–1.872) are more aggregated than their predators (b=1.254–1.393). Taylor's regression technique suggests that pyrethroid applications causedP. ulmi, T. urticae, Z. mali andA. fallacis to be less aggregated whileA. schlechtendali was more aggregated. The impact of changes in mite spatial distribution following pyrethroid applications on sampling plans is discussed.     

Sampling plan for the coffee leaf miner Leucoptera coffeella with sex pheromone traps

The population density of the coffee leaf miner Leucoptera coffeella (Guérin-Méneville & Perrottet) (Lep., Lyonetiidae) can be estimated using pheromone traps in coffee fields as male capture reflects this pest damage based on previous correlational study. However, the spatial distribution of pheromone traps and their density are necessary to optimize the sampling procedure with pheromone traps. Therefore, the objectives of the present study were to determine the pheromone trap density required per hectare to sample coffee leaf miner populations and to determine the spatial distribution of the males of this pest species. The males were sampled every 8 days in 12 consecutive evaluations. Taylor's power law and frequency distributions were used to recognize the distribution of the male capture data, which followed a negative binomial distribution. A common K was obtained, allowing the establishment of a single conventional sampling plan for the 12 fields investigated. The adjusted sampling plan requires eight traps in an area of 30 ha for a 25% precision error. Kriging-generated maps allowed the simulation of male captures for 8, 12 and 20 traps per 30 ha and the results were compared with those obtained with absolute sampling resulting in R ²-values of 0.30, 0.57 and 0.60 respectively. The traps were able to identify the more highly infested areas within the field and are a precise and efficient tool for sampling populations of L. coffeella.