585 resultados para Inseticidas - Toxicologia
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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As formigas cortadeiras, pertencentes aos gêneros Atta e Acromyrmex, possuem esse nome pelo hábito que têm de cortar as folhas das plantas. Por este motivo, elas causam danos econômicos, principalmente em áreas de cultura agrícola. Para realizar o controle dessas pragas, existem inúmeros métodos; porém, os únicos que apresentam resultados satisfatórios são os que utilizam inseticidas tradicionais. O controle químico pode gerar efeitos maléficos ao ambiente, à fauna e à população humana. É por isso que há uma grande procura por métodos alternativos, utilizando produtos que tenham grande especificidade e sejam passíveis de rápida degradação, sendo, portanto, menos danosos ao ambiente. Uma destas alternativas é a utilização de produtos naturais presentes nos vegetais superiores, que podem constituir novas fontes de material com ação tóxica para estes insetos praga. Este trabalho teve por objetivo avaliar a toxicidade das plantas Magonia pubescens e Duguetia lanceolata para operárias de Atta sexdens rubropilosa. Para os testes, as formigas foram divididas em lotes de 50 operárias, distribuídas em 5 placas para cada tratamento e mantidas em B.O.D. durante os 25 dias do experimento. Nos bioensaios de ingestão, os extratos provenientes das plantas foram incorporados em dieta artificial e testados durante 25 dias. No bioensaio tópico, as substâncias eram colocadas no pronoto das formigas e era oferecida dieta pura em todos os dias do experimento. Após os testes, os dados foram transferidos para o software Prisma 3.0, para a confecção de curvas de sobrevivência e para a realização das análises estatísticas. Apesar de Magonia pubescens apresentar um bom resultado, não foi possível continuar com os testes, pois a alta polaridade dos extratos impossibilitava a separação das substâncias... (Resumo completo, clicar acesso eletrônico abaixo)
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In this study were carried out toxicity tests and the evaluation of sub lethal effects of the insecticides malathion and fipronil, over the test system of Girardia tigrina, using for these analyses a great variety of methods. For evaluation of the lethal concentrations of the products, adult planarians were exposed to several different concentrations. All the tests were carried out in duplicate, maintained on the shelter of the light, on a temperature 24-26ºC and they had the duration of 96h, with observations at each 24h. The results were statically valued by the tests U of Mann- Whitney, Spearman-Karber, ANOVA and Pearson correlation. The effects over the system-test, in the different tested concentrations, varied in accordance with the time of exposition. The EC50 given by the test of Spearman-Karber was of 12,5mg/L for malathion and 13,4mg/L for fipronil. The evaluation of sub lethal effects was composed by analyses of the potential of regeneration; histological, for tissue damage evaluation; d; and the “comet assay”, for DNA damage detection. The specimens split up and exposed to the insecticides demonstrated, between other effects, retardation in development of the regenerative blastema. The histological evaluation has shown that exposed planarians to lower concentrations of the insecticides cause more significant damage against the tissues and some specific cell types. Through the comet assay, significant damages were noticed in the DNA in all the treatments, when compared with the control group. Such damages may result in reproduction and immunity alterations, which reduce the competitive efficiency and, consequently, the survival chances of these organisms.
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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)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV
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The aim of this work was study the selectivity of insecticides in favor of natural enemies in cotton (Gossypium hirsutum latifolium Hurtch Lr), DeltaOpal cultivar, in the city of Malhada (BA), and to know the associated beneficial fauna. The study was conducted at the agricultural year of 2010/2011. The design was conducted in randomized blocks with six treatments and four replications. The treatments were: (1) Fipronil 200 SC (0.38 L.ha-1); (2) Alphacypermethrin 100 SC (0.30 L.ha-1), (3) Lufenuron 50 EC (0.30 L.ha-1), (4) Imidacloprid 200 SC (0.30 L.ha-1), (5) Methyl parathion 600 EC (1.00 L.ha-1), and (6) control (water). The product was applied 80 days after emergence, and the evaluations were performed one day before application and 1, 7 and 14 days after application (DAA). The samples were taken using the sampling method beating cloth and Moericke traps. Natural enemies were brought to the laboratory for sorting, counting and identification by family. The toxicity of the products ranged according to the group of natural enemies. Imidacloprid is selective to the spiders and insecticides are moderately toxic (Methyl Parathion and Alphacypermethrin: 1 and 14th DAA; Lufenuron: 14th DAA) or toxic (Fipronil and Alphacypermethrin: 7th DAA). Fipronil (1 DAA), Alphacypermethrin (7th DAA) and Methyl Parathion (14th DAA) are moderately toxic to adult ladybirds. The analyzed insecticides are toxic to the larvae of ladybirds, with more impact until seven days after the application, with the exception of Methyl Parathion classified, as innocuous until this period. The occurrence of 13 families of spiders and 18 families of parasitic Hymenoptera is registered in cotton agroecosystems in the region of Malhada, in the state of Bahia.
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Tese de mestrado, Medicina Legal e Ciências Forenses, Universidade de Lisboa, Faculdade de Medicina, 2016
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
