Measurement of non‐randomness in spatial distributions

Green, Roger H.

doi:10.1007/bf02524740

Cited by 211 publications

(175 citation statements)

References 14 publications

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“…To study the degree of aggregation of the mites, we used the following indices of aggregation: variance/mean ratio (I) (RABINOvICH, 1980) (GREEN, 1966), and k parameter of negative binomial distribution (BLISS and FISHER, 1953;SOuTHWOOD, 1978;ELLIOT, 1979), calculated using the maximum likelihood method. The data were tested for fit with Poisson and negative binomial distributions using the chi-square goodness-of-fit test.…”

Section: Methodsmentioning

confidence: 99%

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SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

et al. 2016

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ABSTRACT-Among the pests of citrus, one of the most important is the red and black flat mite Brevipalpus phoenicis (Geijskes), which transmits the Citrus leprosis virus C (CiLv-C). When a rational pest control plan is adopted, it is important to determine the correct timing for carrying out the control plan. Making this decision demands constant follow-up of the culture through periodic sampling where knowledge about the spatial distribution of the pest is a fundamental part to improve sampling and control decisions. The objective of this work was to study the spatial distribution pattern and build a sequential sampling plan for the pest. The data used were gathered from two blocks of valencia sweet orange on a farm in São Paulo State, Brazil, by 40 inspectors trained for the data collection. The following aggregation indices were calculated: variance/ mean ratio, Morisita index, Green's coefficient, and k parameter of the negative binomial distribution. The data were tested for fit with Poisson and negative binomial distributions using the chi-square goodness of fit test. The sequential sampling was developed using Wald's Sequential Probability Ratio Test and validated through simulations. We concluded that the spatial distribution of B. phoenicis is aggregated, its behavior best fitted to the negative binomial distribution and we built and validated a sequential sampling plan for control decision-making. Index terms: red and black flat mite, negative binomial, Poisson distribution, decision making, integrated pest management. DISTRIBUIÇÃO ESPACIAL E AMOSTRAGEM SEQUENCIAL DE Brevipalpus phoenicis EM CITRUSRESUMO-Dentre as pragas dos citros, uma das mais importantes é o ácaro da leprose Brevipalpus phoenicis (Geijskes), que transmite o vírus da leprose dos citros (CiLv-C). Quando um plano racional de controle de pragas é adotado, é importante se determinar o tempo correto para se dar início ao plano de controle. Para tanto, é necessário acompanhamento constante da cultura através de amostragens periódicas, onde o conhecimento do comportamento espacial da praga é fundamental. O objetivo deste trabalho foi estudar o padrão de distribuição espacial e desenvolver um plano de amostragem sequencial para a praga. Os dados utilizados foram coletados em dois talhões de laranja valência em uma fazenda no estado de São Paulo, Brasil, por 40 inspetores treinados para a atividade.

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Section: Methodsmentioning

confidence: 99%

“…Negative values indicate a uniform distribution. Positive, small values indicate a random distribution, and values close to one indicate maximum contagion (Green, 1966). C x is determined using the following formula:…”

Section: Methodsmentioning

confidence: 99%

SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

et al. 2016

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“…A) Mean Daily Discharge (MDD) in the River Garonne between January 1994 and May 2000, with B) MDD for the period prior to and after the spate on 14-15 September 1998 (the double arrows indicate the 24-h sampling periods on 7-8 and 23-24 September 1998). Green's (1966) index, which is considered the only such index that is little influenced by differences in sample number (Elliot 1977) : ID = (s 2 I -)-1/n I --1, where s 2 is the variance, I -is the mean and n is the number of samples.…”

Section: Methodsmentioning

confidence: 99%

Diel dynamics of young and small fishes in a side-channel of the River Garonne, France, before and after a late-summer spate

Mastrorillo

Copp

2005

Ann. Limnol. - Int. J. Lim.

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“…Para este índice, valores negativos indicam padrão de distribuição uniforme, enquanto valores positivos indicam padrão agregado (Green 1966). Baseia-se na razão variância/média da distribuição e é dado por: Valores negativos indicam distribuição uniforme, valores baixos e positivos (k < 2), disposição altamente agregada, valores variando de dois a oito, agregação moderada e valores superiores a oito distribuição aleatória (Elliott 1979).…”

Section: íNdice De Morisitaunclassified

Distribuição espacial de Tenuipalpus heveae Baker (Acari: Tenuipalpidae) na cultura da seringueira

Martins¹,

Vieira²,

Barbosa³

et al. 2010

Neotrop. entomol.

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-The objective of this work was to study the spatial distribution of Tenuipalpus heveae Baker in rubber tree plantations. The experimental area was located in Marinópolis, State of São Paulo, and corresponded to a total of 1,000 plants (clone RRIM 600) divided in 100 plots of ten plants each. A total of 16 samplings were conducted, approximately once every 10 days, between December 2007 and June 2008. On each date, samples were taken from two plants per plot, each sample corresponding to the top 30 cm of a branch randomly taken from the median region of the canopy of each plant. The number of T. heveae was evaluated on three leaflets randomly taken from each sample, using a 20x power pocket magnifying glass. The number of mites was evaluated in two areas of 1 cm 2 delimited on the lower surface of each leaflet, being one along the midrib and the other along a lateral vein. The calculated dispersion indexes were: variance/mean relationship (I), index of Morisita (Iδ), coefficient of Green (Cx) and k exponent of negative binomial distribution. Tenuipalpus heveae showed aggregate distribution. The negative binomial distribution model was the most appropriate to represent the spatial distribution of the mite in the rubber tree plantation.

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Measurement of non‐randomness in spatial distributions

Cited by 211 publications

References 14 publications

SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

Diel dynamics of young and small fishes in a side-channel of the River Garonne, France, before and after a late-summer spate

Distribuição espacial de Tenuipalpus heveae Baker (Acari: Tenuipalpidae) na cultura da seringueira

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