Spatial distribution and colonization pattern of Bemisia tabaci in tropical tomato crops

2020 ◽  
Author(s):  
Arthur V Ribeiro ◽  
Rodrigo S Ramos ◽  
Tamíris A Araújo ◽  
João R S Soares ◽  
Jhersyka da S Paes ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Bemisia Tabaci ◽  
Colonization Pattern

Population Ecology and Spatial Distribution of Whitefly, Bemisia tabaci, (Homoptera: Aleyrodidae) on Brinjal

2021 ◽  
pp. 54-61
Author(s):  
Z. Mohd Rasdi ◽  
I. Fauziah ◽  
K. Fairuz ◽  
M. S. Mohd Saiful
Keyword(s):  
Spatial Distribution ◽  
Bemisia Tabaci ◽  
Population Ecology

Temporal and spatial distribution of Bemisia tabaci on different host plants

2012 ◽  
Vol 32 (1) ◽  
pp. 176-182 ◽  
Author(s):  
崔洪莹 CUI Hongying ◽  
戈峰 GE Feng
Keyword(s):  
Spatial Distribution ◽  
Bemisia Tabaci ◽  
Host Plants ◽  
Temporal And Spatial Distribution ◽  
Temporal And Spatial

Population Dynamics and Distribution of Trialeurodes vaporariorum and Bemisia tabaci (Homoptera: Aleyrodidae) on Poinsettia Following Applications of Three Chemical Insecticides

1993 ◽  
Vol 28 (1) ◽  
pp. 126-135 ◽  
Author(s):  
T. X. Liu ◽  
R. D. Oetting ◽  
G. D. Buntin
Keyword(s):  
Population Dynamics ◽  
Spatial Distribution ◽  
Bemisia Tabaci ◽  
Trialeurodes Vaporariorum ◽  
Immature Stages ◽  
Single Application ◽  
Sweetpotato Whitefly ◽  
Greenhouse Whitefly ◽  
Insecticide Application ◽  
The Third

The effects of three insecticides, bifenthrin, endosulfan and aldicarb, on the within- and between-plant distributions of both greenhouse whitefly (GHWF), Trialeurodes vaporariorum (Westwood), and sweetpotato whitefly (SPWF), Bemisia tabaci (Gennadius), were examined on greenhouse-grown poinsettia using Taylor's Power Law. Insecticide applications affected the spatial distribution of GHWF and SPWF. The populations of immatures of both species surviving an insecticide application on poinsettia were less aggregated within and between plants than untreated populations. Among the three insecticides, the efficacy against the two whiteflies was not significantly different at the end of the seventh week when multiple applications were conducted. Aldicarb caused higher mortality of immature stages than bifenthrin and endosulfan after four weeks following a single application. A single application of bifenthrin and endosulfan affected the distribution of all whitefly stages in the first and second weeks after treatment, whereas aldicarb did not affect the whitefly population until the third week. Insecticidal treatments had little effect on the stratification of whitefly stages within the plant.

scholarly journals Spatial Distribution of Whitefly Species (Hemiptera: Aleyrodidae) and Identification of Secondary Bacterial Endosymbionts in Tomato Fields in Costa Rica

2020 ◽  
Vol 113 (6) ◽  
pp. 2900-2910
Author(s):  
Xareni Can-Vargas ◽  
Natalia Barboza ◽  
Eric J Fuchs ◽  
Eduardo J Hernández
Keyword(s):  
Spatial Distribution ◽  
Costa Rica ◽  
Bemisia Tabaci ◽  
Restriction Analysis ◽  
Trialeurodes Vaporariorum ◽  
Cytochrome C Oxidase I ◽  
Tomato Production ◽  
Predominant Species ◽  
Pcr Rflp ◽  
Bacterial Endosymbionts

Abstract In Costa Rica, tomato (Solanum lycopersicum Linnaeus) Linnaeus (Solanales: Solanaceae) is one of the crops most severely affected by the whiteflies (Hemiptera: Aleyrodidae) Trialeurodes vaporariorum (Westwood) and the Bemisia tabaci (Gennadius) species complex. The objective of this study was to monitor the spatial distribution and diversity of these species and to detect the presence of secondary bacterial endosymbionts in individuals collected in areas of intensive tomato production. In total, 628 whitefly individuals were identified to the species level using restriction analysis (PCR-RFLP) of a fragment of the mitochondrial cytochrome C oxidase I gene (mtCOI). Trialeurodes vaporariorum was the predominant species, followed by B. tabaci Mediterranean (MED). Bemisia tabaci New World (NW) and B. tabaci Middle East-Asia Minor 1 (MEAM1) were present in lower numbers. The mtCOI fragment was sequenced for 89 individuals and a single haplotype was found for each whitefly species. Using molecular markers, the 628 individuals were analyzed for the presence of four endosymbionts. Arsenophonus Gherna et al. (Enterobacterales: Morganellaceae) was most frequently associated with T. vaporariorum, whereas Wolbachia Hertig (Rickettsiales: Anaplasmataceae) and Rickettsia da Rocha-Lima (Rickettsiales: Rickettsiaceae) were associated with B. tabaci MED. This study confirmed that B. tabaci NW has not been completely displaced by the invasive species B. tabaci MED and B. tabaci MEAM1 present in the country. An association was found between whitefly species present in tomato and certain secondary endosymbionts, elevation was the most likely environmental factor to affect their frequency.

scholarly journals Spatial distribution of soybean plants infested with whitefly Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae)

2018 ◽  
Vol 85 (0) ◽  
Author(s):  
Renato Suekane ◽  
Paulo Eduardo Degrande ◽  
Elmo Pontes de Melo ◽  
Thiago Moreira Azambuja ◽  
Carlos Tutida Menegati
Keyword(s):  
Spatial Distribution ◽  
Bemisia Tabaci ◽  
Sampling Methods ◽  
Chi Square ◽  
Frequency Distributions ◽  
Average Percentage ◽  
Theoretical Frequency ◽  
Chi Square Test ◽  
Soybean Plants

ABSTRACT: The determination of the spatial distribution of a pest is the first step in the establishment of a sampling plan, as sampling methods are contingent upon the type of spatial distribution of the specific pest studied, varying according to the number and size of samples in the area. This work aimed to study the spatial distribution of soybean plants infested with Bemisia tabaci, under field conditions, through the determination of the aggregation indices and the chi-square test of fitness to the main types of theoretical frequency distributions. The average percentage of whitefly (B. tabaci) infestation increasing after the V1 stage, reaching the maximum infestation of 60.3% in the R1 stage. At the R2 stage, the percentage of infestation ranged from 20 to 40%. According to the models of theoretical distributions studied, the Poisson distribution best defines the distribution of the whitefly.

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

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