scholarly journals Spatial distribution of parasitism on Phyllocnistis citrella Stainton, 1856 (Lepidoptera: Gracillariidae) in citrus orchards

2008 ◽  
Vol 68 (4) ◽  
pp. 813-817 ◽  
Author(s):  
SM. Jahnke ◽  
LR. Redaelli ◽  
LMG. Diefenbach ◽  
CF. Efrom
Keyword(s):  
Spatial Distribution ◽  
Negative Binomial ◽  
Leaf Miner ◽  
Phyllocnistis Citrella ◽  
The North ◽  
Binomial Distributions ◽  
Solar Exposure ◽  
Significant Difference ◽  
Citrus Orchards ◽  
East And West

Many species of microhymenopterous parasitoids have been registered on Phyllocnistis citrella, the citrus leafminer. The present study aimed to identify the spatial distribution pattern of the native and introduced parasitoids of P. citrella in two citrus orchards in Montenegro, RS. The new shoots from 24 randomly selected trees in each orchard were inspected at the bottom (0-1.5 m) and top (1.5-2.5 m) stratum and had their position relative to the quadrants (North, South, East and West) registered at every 15 days from July/2002 to June/2003. The leaves with pupae were collected and kept isolated until the emergence of parasitoids or of the leaf miner; so, the sampling was biased towards parasitoids that emerge in the host pupal phase. The horizontal spatial distribution was evaluated testing the fitness of data to the Poisson and negative binomial distributions. In Montenegrina, there was no significant difference in the number of parasitoids and in the mean number of pupae found in the top and bottom strata (χ2 = 0.66; df = 1; P > 0.05) (χ2 = 0.27; df =1; P > 0.05), respectively. In relation to the quadrants, the highest average numbers of the leafminer pupae and of parasitoids were registered at the East quadrant (χ2 = 11.81; df = 3; P < 0.05), (χ2 = 10.36; df = 3; P < 0.05). In the Murcott orchard, a higher number of parasitoids was found at the top stratum (63.5%) (χ2 = 7.24; df =1 P < 0.05), the same occurring with the average number of P. citrella pupae (62.9%) (χ2 = 6.66; df = 1; P < 0.05). The highest number of parasitoids and of miners was registered at the North quadrant (χ2 = 19. 29; df = 3; P < 0.05), (χ2 = 4.39; df = 3; P < 0.05). In both orchards, there was no difference between the numbers of shoots either relative to the strata as well as to the quadrants. As the number of shoots did not varied much relative to the quadrants, it is possible that the higher number of miners and parasitoids in the East and West quadrants would be influenced by the higher solar exposure of these quadrants. The data of the horizontal spatial distribution of the parasitism fit to the negative binomial distribution in all sampling occasions, indicating an aggregated pattern.

DISTRIBUTION OF INSECTS IN SOYBEAN FIELDS

1976 ◽  
Vol 108 (7) ◽  
pp. 767-771 ◽  
Author(s):  
Merle Shepard ◽  
G. R. Carner
Keyword(s):  
Spatial Distribution ◽  
Spatial Patterns ◽  
Trichoplusia Ni ◽  
Negative Binomial ◽  
Insect Pests ◽  
Distribution Patterns ◽  
Epilachna Varivestis ◽  
Anticarsia Gemmatalis ◽  
Poisson Series ◽  
Binomial Distributions

AbstractA 3-year study of spatial distribution patterns of insect pests in soybean fields revealed that the Poisson series described the distribution of most species. These species were: green cloverworms, Plathypena scabra (Fabricius); velvetbean caterpillars, Anticarsia gemmatalis Hübner; loopers Trichoplusia ni (Hübner), Pseudoplusia includens (Walker), and Heliothis spp. The Poisson with zeros distribution was second in characterizing the spatial patterns of many of the species. Field counts of Mexican bean beetles, Epilachna varivestis Mulsant, fitted the Neyman’s type A and negative binomial distributions most often.

Food-plants of Citrus Leaf-miner (Phyllocnistis citrella Stn.) in the Punjab

1951 ◽  
Vol 42 (2) ◽  
pp. 311-316 ◽  
Author(s):  
Abdul Latif ◽  
Ch. Muhammad Yunus
Keyword(s):  
Economic Importance ◽  
Food Plants ◽  
Leaf Miner ◽  
Breeding Ground ◽  
Aegle Marmelos ◽  
Phyllocnistis Citrella ◽  
Citrus Leaf ◽  
Citrus Medica ◽  
Citrus Orchards

The Citrus Leaf-miner (Phyllocnistis citrella) has been recorded from plants belonging to several widely differing botanical families.It is shown that the true food-plants of this pest are the various species of Citrus and Aegle marmelos.Elephant lemon (Citrus medica), which has comparatively succulent leaves, is the most susceptible species of Citrus, whilst lime (C. aurantiifolia), with its comparatively thick and coarse leaves, is the least susceptible. Aegle marmelos is not of any importance as the attack in this case is negligible.C. medica should be excluded from citrus orchards as it is of least economic importance, and is highly susceptible to attack. C. limonia, which is usually grown as a hedge around gardens, provides an undisturbed breeding ground for the pest and should as far as possible not be planted around citrus plantations.

scholarly journals SPATIAL DISTRIBUTION OF Chrysodeixis includens EGGS (WALKER, 1858) (LEPIDOPTERA: NOCTUIDAE) IN SOYBEAN CROP

2019 ◽  
Vol 17 (2) ◽  
pp. 51 ◽  
Author(s):  
Leandro Aparecido De Souza ◽  
José Carlos Barbosa ◽  
João Henrique Silva Carvalho ◽  
Leticia Serpa dos Santos ◽  
Diego Felisbino Fraga ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Probabilistic Models ◽  
Negative Binomial ◽  
Binomial Distributions ◽  
Egg Distribution ◽  
Morisita Index ◽  
Lepidoptera Noctuidae ◽  
Chrysodeixis Includens

Among pest insects that attack soybean crops, Chrysodeixis includens (Walker, 1858) (Lepidoptera: Noctuidae) looper caterpillar deserves attention due to its key pest status in soybean crops. The spatial distribution of C. includens eggs should be investigated in order to understand the behavior of this species in the area. The aim of this study was to investigate the spatial distribution of C. includens eggs in soybean crops. The experiment was conducted with SYN 9070 RR soybean variety in an experimental area of the Teaching, Research and Extension Farm (FEPE) of FCAV/ UNESP, Jaboticabal, SP, Brazil. The area of 0.6 ha was divided into 60 equidistant plots of 100 m² each. For the study of the spatial distribution of P. includens eggs in the area, the following dispersion indexes were used: variance / mean ratio (I), Morisita index (Id), Green coefficient (Cx), k exponent of the negative binomial distribution for each sampling. Regarding the probabilistic models that describe the spatial distribution of a given variable, the data adjustment to the Poisson and negative binomial distributions was tested. According to values obtained for dispersion indexes, egg distribution occurred in an aggregate way, and the negative binomial distribution was the most appropriate probabilistic model to represent the distribution of C. includens eggs in the study area.

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

2008 ◽  
Vol 68 (1) ◽  
pp. 205-210 ◽  
Author(s):  
CR. Jesus ◽  
LR. Redaelli
Keyword(s):  
Spatial Distribution ◽  
Citrus Sinensis ◽  
Random Distribution ◽  
Leaf Miner ◽  
Citrus Reticulata ◽  
Sampling Occasion ◽  
Citrus Species ◽  
Phyllocnistis Citrella ◽  
Tree Crowns ◽  
Citrus Deliciosa

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 (29º 68’ S and 51º 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.

Spatial Distribution of Broadleaf Weeds in North Carolina Soybean (Glycine max) Fields

Weed Science ◽  
1992 ◽  
Vol 40 (4) ◽  
pp. 554-557 ◽  
Author(s):  
Lori J. Wiles ◽  
Glenn W. Oliver ◽  
Alan C. York ◽  
Harvey J. Gold ◽  
Gail G. Wilkerson
Keyword(s):  
North Carolina ◽  
Spatial Distribution ◽  
Glycine Max ◽  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Negative Binomial ◽  
Individual Species ◽  
Frequency Distributions ◽  
Binomial Distributions ◽  
High Degree

Spatial distribution of broadleaf weeds within 14 North Carolina soybean fields was characterized by fitting negative binomial distributions to frequency distributions of weed counts in each field. In most cases, the data could be represented by a negative binomial distribution. Estimated values of the parameter K of this distribution were small, often less than one, indicating a high degree of patchiness. The data also indicated that the population as a whole was patchy. Counts of individual species were positively correlated with each other in some fields and total weed count could be represented by a negative binomial for 12 of the 14 fields.

scholarly journals Spatial distribution of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) in citrus orchards

2010 ◽  
Vol 67 (5) ◽  
pp. 546-554 ◽  
Author(s):  
Marilia Gregolin Costa ◽  
José Carlos Barbosa ◽  
Pedro Takao Yamamoto ◽  
Renata Moreira Leal
Keyword(s):  
Spatial Distribution ◽  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Negative Binomial ◽  
Sweet Orange ◽  
Central Area ◽  
Diaphorina Citri ◽  
Paulo State ◽  
Dispersion Indices ◽  
Citrus Orchards

The psyllid Diaphorina citri Kuwayama is one of the most important pests of citrus, mainly because it is the vector of the bacterium that causes huanglongbing (HLB) or 'Greening' disease. To study the spatial distribution of nymphs and adults of this pest, an experiment was carried out in two 'Valencia' sweet orange orchards, four and 12 years of age, established in Matão, central area of São Paulo state, Brazil. The following dispersion indices were used to study pest aggregation in the citrus plants: variance/mean relationship (I), index of Morisita (Iδ), coefficient of Green (Cx), the <img border=0 width=16 height=16 src="../../../../../img/revistas/sa/v67n5/a08form10.gif" align=absmiddle>exponent of negative binomial distribution, common k (<img border=0 width=16 height=16 src="../../../../../img/revistas/sa/v67n5/a08form10.gif" align=absmiddle>c) and Taylor's Power Law for each sampling. The negative binomial distribution was more representative of the spatial distribution of this psyllid, for both nymphs and adults. For most samplings, psyllid nymphs found in branches and adults caught in traps had an aggregated distribution.

The Scottish Herring Trade, 1470–1600

2005 ◽  
Vol 84 (2) ◽  
pp. 149-165 ◽  
Author(s):  
Martin Rorke
Keyword(s):  
Sixteenth Century ◽  
West Coast ◽  
North West ◽  
Capital Costs ◽  
The North ◽  
East And West

This paper uses customs figures to show that herring exports from the east and west coast lowlands expanded significantly in the last six decades of the sixteenth century. The paper argues that the rise was primarily due to the north-west Highland fisheries being opened up and exploited by east and west coast burghs. These ventures required greater capital supplies and more complex organisation than their local inshore fisheries and they were often interrupted by political hostilities. However, the costs were a fraction of those required to establish a deepwater buss fleet, enabling Scotland to expand production and take advantage of European demand for fish while minimising additional capital costs.

RENDIMENTO DE CULTIVARES DE CAUPI (Vigna unguiculata L Walp.) SUBMETIDAS À DIFERENTES LÂMINAS DE IRRIGAÇÃO

Irriga ◽  
1999 ◽  
Vol 4 (3) ◽  
pp. 139-144 ◽  
Author(s):  
Gianini Peixoto Bezerra Lima ◽  
José Vanglesio de Aguiar ◽  
Raimundo Nonato Távora Costa ◽  
Vital Pedro da Silva Paz
Keyword(s):  
Vigna Unguiculata ◽  
Irrigation System ◽  
Northeast Brazil ◽  
Marginal Product ◽  
Applied Water ◽  
Cowpea Cultivars ◽  
The North ◽  
Significant Difference ◽  
Caixa Postal ◽  
Water Depths

RENDIMENTO DE CULTIVARES DE CAUPI (Vigna unguiculata L Walp.) SUBMETIDAS À DIFERENTES LÂMINAS DE IRRIGAÇÃO1       Gianini Peixoto Bezerra Lima José Vanglesio de Aguiar Raimundo Nonato Távora Costa Universidade Federal do Ceará – Departamento de Engenharia Agrícola. Campus do Pici. Bloco 804. CEP 60455-760 – Fortaleza-CE Vital Pedro da Silva Paz Escola Superior de Agricultura Luiz de Queiroz – Departamento de Engenharia Rural, bolsista da FAPESP. Av. Pádua Dias, 11 – Caixa Postal 11. 13418-900 – Piracicaba-SP       1 RESUMO       O caupi é um dos cultivos mais tradicionais do Norte e Nordeste do Brasil, constituindo alimento básico nestas regiões. Com este trabalho foi possível estabelecer relações entre a quantidade de água aplicada e produtividade de grãos, para três variedades de feijão caupi submetidas a diferentes lâminas de água. Para caracterização das lâminas de água foi utilizado um sistema de irrigação por aspersão convencional em linha. O controle da irrigação foi realizado a partir de tensiômetros instalados à 15 cm de profundidade. Os resultados mostraram que: i) a cultivar João Paulo II apresentou melhores resultados de produtividade para as lâminas de água aplicadas que variaram de T1 = 291,8 mm a T5 = 141,2 mm; ii) sob condições de reduzida disponibilidade de água, ou seja, menor lâmina aplicada, não ocorreu diferença estatística  para a produtividade entre as cultivares estudadas; e iii) para as condições do estudo, a cultivar Setentão apresentou a menor taxa de redução do produto marginal.       UNITERMOS: caupi, irrigação, função de produção       LIMA, G. P. B., AGUIAR, J. V., COSTA, R. N. T., PAZ, V. P. S. Responses OF cowpea cultivars (Vigna unguiculata L Walp) at differents irrigation deficits     2 ABSTRACT       The caupi is one of the most traditional cultivation of the north and northeast - Brazil, constituting a basic food in these areas. With this work it was possible to establish relationships between the amount of water applied and productivity of grains, for three caupi varieties submitted to different irrigation sheets. To diferentiate water depths in the irrigation system, the aspersion in line was used. The control of the irrigation was accomplished using tensiometers installed to 15 cm of depth. The results showed that: i) the João Paulo II variety presented better productivity for the applied water depths; ii) under reduced conditions of water avai lability for study conditions, these was no significant difference in the productivity reached among the cultivars studied; and iii) for the conditions of the study, the variety Setentão presented the smallest rate of reduction of the marginal product.       KEYWORDS: cowpea, irrigation, production function  

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