Common bean resistance expression to whitefly in winter and rainy seasons in Brazil

Whitefly Bemisia tabaci (Gennadius) biotype B is the major pest of common bean (Phaseolus vulgaris L.) in Brazil and other countries. Host plant resistance is one of the cornerstones of Integrated Pest Management (IPM), and assessment of cultivars for insect resistance is fundamental to provide farmers options for pest control. This study evaluated common bean resistance to whitefly in the winter and rainy seasons in Jaboticabal, Brazil, and correlated the infestation with climatic factors. The plant part and development period of common bean that are more susceptible to whitefly infestation were also examined for potential use in IPM. Field experiments were carried out using 18 and 19 commercial cultivars in the winter and rainy seasons, respectively. Whitefly eggs, nymphs, and adults in the upper part and lower part of plants were sampled from 25 to 60 days after emergence (DAE). Cultivars IAC-Una and IAC-Eldorado had less oviposition and the former also showed lower adult infestation in the winter season. In the rainy season, cultivars IAPAR-81 and Guará had a smaller number of eggs, whereas IAC-Centauro was less infested by nymphs. The number of nymphs and adults was similar among cultivars in the winter and rainy seasons, respectively. The upper part of plants had a greater number of eggs and adults, while, the lower part harbored larger numbers of nymphs. Common bean was more susceptible to whitefly at 25-32 DAE in both seasons. These results add useful information to IPM of whitefly in common bean.

Common bean resistance expression to whitefly in winter and rainy seasons in Brazil

Whitefly Bemisia tabaci (Gennadius) biotype B is the major pest of common bean (Phaseolus vulgaris L.) in Brazil and other countries. Host plant resistance is one of the cornerstones of Integrated Pest Management (IPM), and assessment of cultivars for insect resistance is fundamental to provide farmers options for pest control. This study evaluated common bean resistance to whitefly in the winter and rainy seasons in Jaboticabal, Brazil, and correlated the infestation with climatic factors. The plant part and development period of common bean that are more susceptible to whitefly infestation were also examined for potential use in IPM. Field experiments were carried out using 18 and 19 commercial cultivars in the winter and rainy seasons, respectively. Whitefly eggs, nymphs, and adults in the upper part and lower part of plants were sampled from 25 to 60 days after emergence (DAE). Cultivars IAC-Una and IAC-Eldorado had less oviposition and the former also showed lower adult infestation in the winter season. In the rainy season, cultivars IAPAR-81 and Guará had a smaller number of eggs, whereas IAC-Centauro was less infested by nymphs. The number of nymphs and adults was similar among cultivars in the winter and rainy seasons, respectively. The upper part of plants had a greater number of eggs and adults, while, the lower part harbored larger numbers of nymphs. Common bean was more susceptible to whitefly at 25-32 DAE in both seasons. These results add useful information to IPM of whitefly in common bean.(AU)

Spatial distribution of cases of fatal yellowing on organic oil palm plantation / Distribuição espacial de casos de amarelecimento fatal em plantio orgânico de palma de óleo

This work studied the spatial dispersion of cases of fatal yellowing (FY) in an oil palm plantation in Acará, Pará State, Brazil. Data were collected monthly from two areas, divided in 16 quadrants each, for a 24 month period (2012-2013). In each quadrant, 138 plants were evaluated. The number of diseased plants was counted in twenty planting lines, and the spatial pattern of the disease was analyzed. The following spatial analysis techniques were used: common sequences of runs, doublets and quadrants. We also determined the levels of disease aggregation in the sectors. Plants with FY had a spatial distribution aggregated in a lower line number when using the run analysis than when using the doublets method. Aggregation of FY cases was observed in 30% of the evaluated lines. The quadrant analysis confirmed the existence of case aggregation, with vertical and horizontal distribution. The existence of disease forming foci suggests that FY probably has biotic origin. Additional studies are required to confirm this hypothesis.

O trabalho teve por objetivo estudar a dispersão espacial de casos de amarelecimento fatal (FY) em plantio de palma de óleo no município de Acará, Estado do Pará, Brasil. Os dados da incidência de FY foram coletados em inspeções mensais, durante vinte e quatro meses (2012 e 2013) em duas subáreas, com dezesseis quadrantes cada. Foram avaliadas 138 plantas em cada quadrante. Em vinte linhas de plantio foram contados o número de plantas doentes e feita análise do arranjo espacial da doença. As técnicas de análise espacial utilizadas foram: a sequências ordinárias de runs, doublets e quadrantes. Também foram determinados índices de agregação da doença nas subáreas. Plantas com FY apresentaram distribuição espacial agregada em número menor de linha quando utilizando a metodologia de analise de runs que quando utilizada a metodologia de doublets. Verificou-se que em 30% das linhas avaliadas houve agregação de casos de FY. A análise de quadrantes evidenciou a existência de agregação de casos, com distribuição vertical e horizontal. A ocorrência da doença formando reboleiras sugere que o FY tem origem biótica, sendo necessários mais estudos para confirmar a hipótese.

Spatial distribution of cases of fatal yellowing on organic oil palm plantation / Distribuição espacial de casos de amarelecimento fatal em plantio orgânico de palma de óleo

This work studied the spatial dispersion of cases of fatal yellowing (FY) in an oil palm plantation in Acará, Pará State, Brazil. Data were collected monthly from two areas, divided in 16 quadrants each, for a 24 month period (2012-2013). In each quadrant, 138 plants were evaluated. The number of diseased plants was counted in twenty planting lines, and the spatial pattern of the disease was analyzed. The following spatial analysis techniques were used: common sequences of runs, doublets and quadrants. We also determined the levels of disease aggregation in the sectors. Plants with FY had a spatial distribution aggregated in a lower line number when using the run analysis than when using the doublets method. Aggregation of FY cases was observed in 30% of the evaluated lines. The quadrant analysis confirmed the existence of case aggregation, with vertical and horizontal distribution. The existence of disease forming foci suggests that FY probably has biotic origin. Additional studies are required to confirm this hypothesis.(AU)

O trabalho teve por objetivo estudar a dispersão espacial de casos de amarelecimento fatal (FY) em plantio de palma de óleo no município de Acará, Estado do Pará, Brasil. Os dados da incidência de FY foram coletados em inspeções mensais, durante vinte e quatro meses (2012 e 2013) em duas subáreas, com dezesseis quadrantes cada. Foram avaliadas 138 plantas em cada quadrante. Em vinte linhas de plantio foram contados o número de plantas doentes e feita análise do arranjo espacial da doença. As técnicas de análise espacial utilizadas foram: a sequências ordinárias de runs, doublets e quadrantes. Também foram determinados índices de agregação da doença nas subáreas. Plantas com FY apresentaram distribuição espacial agregada em número menor de linha quando utilizando a metodologia de analise de runs que quando utilizada a metodologia de doublets. Verificou-se que em 30% das linhas avaliadas houve agregação de casos de FY. A análise de quadrantes evidenciou a existência de agregação de casos, com distribuição vertical e horizontal. A ocorrência da doença formando reboleiras sugere que o FY tem origem biótica, sendo necessários mais estudos para confirmar a hipótese.(AU)

Resistência de cultivares de feijoeiro, dinâmica populacional de Bemisia tabaci (Genn., 1889) (Hemiptera: Aleyrodidae) e incidência de mosaico dourado

A cultura do feijoeiro (Phaseolus vulgaris L.) pode ser infestada por insetos que afetam a produção antes e após a colheita, tendo como estimativa de perdas causadas nos rendimentos pelas pragas variando de 33 a 86%. Dentre essas pragas a mosca-branca Bemisia tabaci (Genn., 1889) biótipo B (Hemiptera: Aleyrodidae) merece destaque. Esta ocasiona danos diretos decorrentes de sua alimentação e indiretos que ocorrem por meio da excreção açucarada de honeydew ou ?mela? e simbiose com a fumagina. No entanto, o dano mais sério causado pela B. tabaci biótipo B é a transmissão de viroses como o mosaico-dourado-do-feijoeiro, provocando perdas econômicas que podem variar de 30% a 100%. Dessa forma, os objetivos da presente pesquisa foram: avaliar a resistência de cultivares de feijoeiro a B. tabaci biótipo B, discriminar as cultivares quanto aos tipos de resistência envolvidas, classificá-las quanto ao grau de resistência, estudar a não preferência para oviposição e biologia da mosca-branca nas cultivares selecionadas dos ensaios de campo, avaliar a influência dos fatores abióticos (precipitação pluviométrica e temperatura) na dinâmica populacional da praga, além de avaliar a incidência de mosaico dourado na área experimental. Os ensaios foram instalados de junho de 2010 a abril de 2012, todos conduzidos no Departamento de Fitossanidade da FCAV/UNESP ? Campus de Jaboticabal, SP. O estudo consistiu de duas etapas, a campo e em casa de vegetação. Para os testes de campo foram utilizadas as cultivares (tratamentos): IAC-Formoso, IAC-Diplomata, IAC-Una, IAC-Alvorada, IAC-Harmonia, IAC-Galante, IAC-Carioca-Eté, IAC-Centauro, IAC-Carioca-Tybatã, BRS-Supremo, BRS-Requinte, BRS-Pontal, BRS-Cometa, IAPAR-81, IPR-Siriri, IPR-Eldorado, Guará, IPR-139 e Pérola. Posteriormente, as cultivares...

Common bean crop (Phaseolus vulgaris L.) may be attacked by insects, affecting the production before and after the harvest, with the estimative of losses caused by the pests ranging from 33 to 86%. Among these pests, the whitefly Bemisia tabaci (Genn., 1889) biotype B (Hemiptera: Aleyrodidae) stands out. It causes direct damages due to its feeding and indirect through sugary excretion of honeydew and symbiosis with sooty mold. However, the most serious damage caused by B. tabaci biotype B is the transmission of viruses such as the bean golden mosaic, causing economic losses ranging from 30 to 100%. Thus, the objectives of this research were: to evaluate the resistance of bean cultivars to B. tabaci biotype B, discriminate the cultivars regarding the type of resistance involved, classify them regarding the degree of resistance, study the non-preference for oviposition and biology of the whitefly on the cultivars screened from the field assays, assess the influence of abiotic factors (rainfall and temperature) on the population dynamics of the pest, in addition to evaluate the incidence of golden mosaic on the experimental area. The experiments were set up from June 2010 to April 2012, all carried out in the experimental area of the Departamento de Fitossanidade at FCAV/UNESP ? Campus of Jaboticabal, SP. The study consisted of two stages, in the field and greenhouse. For the field tests, the cultivars (treatments) were used: IAC-Formoso, IAC-Diplomata, IAC-Una, IAC-Alvorada, IAC-Harmonia, IAC-Galante, IAC-Carioca-Eté, IAC-Centauro, IAC-Carioca-Tybatã, BRS-Supremo, BRS-Requinte, BRS-Pontal, BRS-Cometa, IAPAR-81, IPR-Siriri, IPR-Eldorado, Guará, IPR-139 and Pérola. After, the cultivars screened in the field experiments were used in greenhouse tests, studying the non-preference for oviposition and antibiosis...

Dinâmica populacional de mosca-negra-dos-citros (Aleurocanthus woglumi Ashby, 1915) em pomares de citros em sistema agroflorestal e monocultura

Entre os insetos pragas que mais preocupam os citricultores no estado do Pará, a mosca-negra-dos-citros, Aleurocanthus woglumi destaca-se por acarretar danos diretos e indiretos ás plantas cítricas, além de constituir praga quarentenária presente ou A2 de alerta máximo, restringindo o comércio com outras regiões. Por ser uma praga exótica, recém introduzida, faltam conhecimentos básicos para a implementação de um manejo adequado na região amazônica. Desse modo, o objetivo do presente trabalho foi avaliar a dinâmica populacional de mosca-negra-dos-citros em pomares de citros em sistema de plantio agroflorestal e monocultura, utilizando a metodologia geoestatística. A área experimental está localizada no município de Capitão Poço onde foram realizadas 12 amostragens durante o período de setembro de 2008 a outubro de 2009, avaliando a presença ou ausência da praga nas laranjeiras em ambos os sistemas de produção. Os resultados obtidos mostraram que o sistema de plantio agroflorestal apresentou maior incidência de plantas com presença de mosca-negra-dos-citros comparado ao sistema de plantio de citros em monocultura, houve influência da temperatura na regulação da população da praga e precipitações elevadas reduziram o número de plantas com presença de A. woglumi. Observou-se que a distribuição espacial da mosca negra dá-se, predominantemente, em agrupamentos com dependência espacial descrita pelo modelo esférico, formando reboleiras de 8,5 a 34m (alcance do modelo) para ambos os sistemas de plantio adotados

Among the insect pests of most concern to citrus growers in the state of Pará (Brazil), the citrus blackfly, Aleurocanthus woglumi stands to cause direct or indirect damage to citrus plants, besides being a pest is present or A2 of this alert, restricting trade with other regions. Being an exotic pest, recently introduced, it lacks basic knowledge for the implementation of appropriate management in the Amazon region. Thus, the objective of this study was to evaluate the population dynamics of blackfly in a citrus orchards from an agroforestry and monoculture plantations, using geostatistical methodology. The experimental area is located in the municipality of Capitão Poço where 12 samples were taken during the period September 2008 to October 2009, evaluating the presence or absence of the pest in orange in both production systems. The results showed that the system of agroforestry plantation had a higher incidence of plants with the presence of citrus blackfly compared with monoculture planting citrus crop, there was influence of temperature on the regulation of pest population and heavy rain reduced the number of plants with presence of A. woglumi. It was observed that the spatial distribution of the blackfly takes place predominantly in clusters with spatial dependence described by the spherical model, forming foci of 8.5 to 34m (range model) for both planting systems adopted