Spatial distribution of citrus leprosis in the Eastern Amazon

Oliveira, Fábio Júnior de; Farias, Paulo Roberto Silva; Silva, Anderson Gonçalves da; Rodrigues, Karjoene Cassimiro Vilar; Araújo, Francisca das Chagas Bezerra de

doi:10.5935/1806-6690.20160007

Cited by 3 publications

(2 citation statements)

References 18 publications

(14 reference statements)

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“…Furthermore, wind speed is also considered an important agent of dispersal (ALvES et al, 2005). Making use of geostatistical methods, a recent study showed an aggregated distribution pattern for the disease (i.e., incidence of CiLV-C), with fitted models showing spatial dependence ranging from 9 to 30 m (OLIvEIRA JR et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

et al. 2016

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“…The local climate is characterized as a tropical climate (Am) with a moderately dry season, with annual average rainfall between 2500-3000 mm. The driest quarter of the year is between September and November (Oliveira et al 2016).…”

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confidence: 99%

Estimation of evapotranspiration and single and dual crop coefficients of acai palm in the Eastern Amazon (Brazil) using the Bowen ratio system

Sousa

Fernandes²,

Tavares

et al. 2021

Irrig Sci

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The acai palm (Euterpe oleracea Mart.) is a fruit from the Amazon that is originally found in flooded areas. Over recent years, its marketability has gained significant interest in Brazil and abroad because of its agronomic, nutritional and economic potential. However, there is a lack of technical-scientific information about crop water requirements for irrigation management during the reproductive phase of acai palm. Therefore, the aim of this research was to estimate the water requirements (crop evapotranspiration (ET c ), single (Kc) and dual (Kcb + Ke) crop coefficients) of acai palm in the Eastern Amazon (Brazil) using the Bowen ratio system. A micrometeorological tower was installed in the center of an experimental area to monitor ET c and meteorological variables. Phenological development was monitored during two growing seasons. Soil water evaporation was determined on a daily scale using weighing microlysimeters. Ke and Kcb values were calculated by the ratio of soil surface evaporation and transpiration to reference evapotranspiration (ET o ), respectively. Total water requirements of the acai palms were 1165 mm, with a daily average of 3.49 mm day −1 for the growing season. The average values of Kc, Ke and Kcb for the acai palm were 1.08; 0.21 and 0.84, respectively. The findings will assist the design of irrigation management protocols for acai trees that are better tailored to satisfy crop water requirements. This will allow improved water use efficiency, ensuring tree crop sustainability.

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Geostatistical modeling of “lethal coconut palm crown atrophy”, a new disease in the State of Pará

Gama¹,

Farias²

2021

Semina: Ciênc. Agrár.

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’Lethal Coconut Palm Crown Atrophy’ (LCCA) is a rapidly spreading disease in Brazil, capable of quickly killing coconut trees and threatening the commercial exploration of this plant. The objective of this work was to characterize the spatial and temporal distribution pattern of LCCA in green dwarf coconut commercial plantation areas, located the municipality of Santa Izabel, mesoregion of Northeastern Pará, Brazil. Surveys were carried out at monthly intervals between January 2014 and December 2018, checking for plants with LCCA-characteristic symptoms. Geostatistics was applied to perform spatial-temporal disease estimates based on semivariogram modeling and preparation of ordinary kriging maps. These spatial estimates are conducted through interpolations that characterize data variability in the area. The spherical model yielded the best fit to the spatial distribution of the disease, as it presented the best coefficient of determination (R²), with the range varying between 14m and 45m. The Spatial Dependence Index (SDI) was moderate in the evaluations carried out between 2014 and 2017 (in the 0.26-0.64 range), but not in 2018, when it was strong (0.23). The values of the clustering intensity of LCCA-symptomatic plants were estimated in non-sampled points. The spherical fit model of the data indicates an aggregated distribution pattern, shown by aggregation patches in the plantation, graded by values of dissemination intensity. The kriging maps allowed the observation that the disease expands between plants in the same line, suggesting the possibility of the presence of a short-range vector.

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Spatial distribution of citrus leprosis in the Eastern Amazon

Cited by 3 publications

References 18 publications

SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

Estimation of evapotranspiration and single and dual crop coefficients of acai palm in the Eastern Amazon (Brazil) using the Bowen ratio system

Geostatistical modeling of “lethal coconut palm crown atrophy”, a new disease in the State of Pará

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