121 resultados para natural control

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Muita atenção tem sido dada ao desenvolvimento de inseticidas vegetais buscando-se um efetivo controle de ectoparasitas de bovinos, sem prejudicar animais, consumidores e meio ambiente. Este estudo, realizado de abril a julho de 2008, na Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Pecuária Sudeste, em São Carlos, SP, Brasil, avaliou a eficácia de uma torta comercial de nim (Azadirachta indica) no controle da mosca-dos-chifres (Haematobia irritans) em bovinos. A torta de nim, misturada ao sal mineral na concentração de 2%, foi fornecida a 20 vacas Nelore, durante nove semanas, e sua eficácia foi monitorada através de contagens semanais nos grupos tratado e controle. Infestações individuais foram registradas por meio de fotos digitais em todos os animais de ambos os grupos, e o número de moscas foi, posteriormente, quantificado com o auxílio de um sistema de análise de imagem computadorizado. A quantificação dos componentes da torta de nim, por cromatografia líquida, revelou a presença de azadiractina (421 mg.kg-1) e 3-tigloyl-azadirachtol (151 mg.kg-1). A adição da torta de nim a 2% reduziu o consumo de sal mineral em cerca de 22%. O tratamento com torta de nim a 2% não reduziu as infestações por mosca-dos-chifres em bovinos durante as nove semanas do estudo.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Species of Ceraeochrysa Adams are distributed from southeast Canada to Argentina. Larvae feed on aphids, thrips, white flies, mites, and neonatal larvae of Lepidoptera in varied agroecosystems. Seven species are known in Venezuela, viz. Ceraeochrysa achillea Freitas & Penny, C. angulata (Navas), C. bitacornua Freitas & Penny, C. caligata (Banks), C. cubana (Hagen), C. everes (Banks), and C. valida (Banks). In this study, three species are described as new to science, Ceraeochrysa melaenopareia sp. nov., Ceraeochrysa pittieri sp. nov., and Ceraeochrysa torresi sp. nov.

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Problem statement: One of the current requirements of agroecosystem management is the maintenance of biodiversity. Manual sugarcane harvesting with the previous burning of straw has been gradually replaced by mechanical harvesting in Brazil. However, the diversity of Formicidae, which can be a natural pest controller, has not been studied in this new system yet. Approach: This study was carried out to assess the diversity of ants in an exclusively mechanically harvested sugarcane culture based on the hypothesis that species richness and abundance will increase with the deposition of straw in this culture system. Ants were sampled using pitfall traps in six sugarcane cultivars during three consecutive harvest cycles. Results: A total of 8,139 ants, distributed in 39 species, were collected. Richness, abundance and diversity differed between harvest cycles, especially in the first cycle, when the soil did not have any straw and in the two last cycles and the straw layer was about 10-15 cm thick. The communities found in the second and third cycles were similar and the maintenance of straw in the culture contributed to a greater species diversity, particularly of generalist predaceous taxa, which may contribute to the natural control of pests. Conclusion: The diversity of ants increased with straw deposition, including of taxa that may be beneficial to the sugarcane culture. However, new studies of the predatory and competition relations in this agroecosystem are necessary. © 2010 Science Publications.

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This study aimed to evaluate the efficiency of natural biocides, brown and green propolis, for the control of bacterial contamination in the production of sugarcane spirit. The treatments consisted of brown and green propolis extracts, ampicillin, and a control and were assessed at the beginning and end of harvest season in ten fermentation cycles. In the microbiological analyses, the lactic acid bacteria were quantified in the inoculum before and after the treatment with biocides, and the viability of yeast cells during fermentation was evaluated. The levels of acids, glycerol, total residual reducing sugars, and ethanol were analyzed for the wine resulting from each fermentation cycle. A reduction in the number of bacterial contaminants in the inoculum in the treatments with the natural biocides was observed, but it did not affect the viability of yeast cells. The control of the contaminants led to the production of higher levels of ethanol and reduced acidity in the wine produced. The results of the use of brown and green propolis to control the growth microorganisms in the fermentation of sugarcane spirit can be of great importance for using alternative strategies to synthetic antibacterials in fermentation processes including other distilled beverage or spirits.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Two studies, of a natural infection and an experimental infection, were performed in order to study congenital transmission of Toxoplasma gondii in cattle. In the first study, 50 fetuses were harvested from gestating cows that were eutanasied at a municipal slaughterhouse in Jaboticabal, São Paulo state, Brazil. In the second study, 11 gestating cows were divided into four groups for inoculation with T. gondii: GI consisted of three cows inoculated with 1.0 x 10(5) oocysts during their first trimester of gestation; GII consisted of three cows inoculated with 1.0 x 10(5) oocysts during their second trimester of gestation; GIII consisted of three cows inoculated with 1.0 x 10(5) oocysts during their last trimester of gestation; and GIV consisted of two control cows, one during its first and the other during its second trimester of gestation. In both studies, the presence of T. gondii was confirmed both indirectly by immunofluorescence assay (IFAT). In the natural infection experiment, 18% (9/50) of the gestating cows were confirmed to have specific antibodies (IFAT - 1:64) against T. gondii. The bioassay was able to diagnose the presence of T. gondii in the tissue samples from three calves. In the second experiment, the nine cows from groups I, II and III presented with specific antibodies (IFAT) against T. gondii. In contrast, T. gondii could not be detected by IFAT, histopathological examination or the bioassay in any of the nine calves born to cows experimentally infected with T. gondii oocysts. Based on the results from both studies, we conclude that congenital infection of T. gondii in cattle, while infrequent, does occur naturally. The pathogenicity of the strain of T. gondii may influence the likelihood of this route of transmission. (C) 2010 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O setor citrícola enfrenta sérios problemas representados por doenças de flores e frutos jovens que, além de diminuir a produtividade, depreciam os frutos pelo aspecto que conferem aos mesmos. Tais doenças são representadas, principalmente, pela mancha preta dos frutos cítricos (MPC) e pela queda prematura dos frutos cítricos (QPFC), onde a medida predominante de controle é a pulverização com produtos químicos. Entretanto, os custos financeiros e ambientais de aplicações com tais produtos, aliado às crescentes restrições à presença de resíduos, estão a exigir o estudo de novas alternativas. Entre estas, o controle biológico surge como alternativa importante. Sabendo-se que, o conhecimento da biodiversidade dos seres vivos é importante para determinação de suas funções potenciais, o presente trabalho teve por objetivo estudar a diversidade genética, através de marcadores moleculares AFLP, de 32 isolados de B. subtilis com a finalidade de se encontrar, dentre os mesmos, um (ou mais isolados) que apresentasse maior similaridade com o isolado ACB-69, o qual apresenta potencial para o controle da doença. Diante disso, os resultados obtidos neste trabalho, permitiram concluir que: a) os isolados de B. subtilis estudados agruparam-se no filograma de distância genética, independente da procedência ou do hospedeiro; b) os isolados ACB-69 e ACB-83, com potenciais para o controle da queda prematura dos frutos cítricos, compartilham da mesma ancestralidade, o que pode ser inferido pela metodologia aplicada; c) em termos biológicos; o isolado ACB-83 merece mais estudos quanto à viabilidade de controle de doenças de citros, como a queda prematura dos frutos cítricos e a manha preta dos frutos cítricos, sob condições de campo.

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The cotton can be damaged by many pests, standing out among them cotton leafworm, responsible for major losses in production, if not controlled properly. A group of natural enemies is the most studied of the family Trichogrammatidae, mainly species of the genus Trichogramma, because of its importance in biological control at the initial stage of development of their hosts. In order to study the natural egg parasitism of Alabama argillacea (Hubner, 1818) (Lepidoptera: Noctuidae) by Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) in different phenological stages of transgenic and conventional varieties of cotton (Gossypium hirsutum L.) in the region of Ipameri, GO, it was carried out this experiment from december 2007 to april 2008, in the UEG, State of Goias. The experimental design was in randomized blocks with five treatments consisting of the conventional varieties DeltaOPAL, FMX 966, FMX 993, FMX 910 and NuOPAL transgenic variety, in four replications. In the beginning of oviposition of the A. argillacea it was started the 27 old days plant and the parasitism increased as the availability of eggs of the host, regardless of variety. It was found that the varieties over the vegetative cycle did not show statistical differences on the preference for oviposition by the moth neither on the parasitism. The level of parasitism of eggs of A. argillacea by T. pretiosum varied depending on the density of eggs on plants, not in terms of varieties and phenological stages.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)