73 resultados para Oidium heveae


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Calacarus heveaeFeres (Eriophyidae) and Tenuipalpus heveae Baker (Tenuipalpidae) can cause heavy defoliation of rubber tree plants. From the perspective of integrated pest management, resistant clones can be an important strategy. The objective of this work was to evaluate the resistance of rubber tree clones to the attack of mites, in an experiment carried out in Votuporanga, SP. The experimental design was a randomized blocks with eighteen treatments and three replications. The treatments were the clones PB 230, PB 243, PB 252, PB 294, PB 306, PB 311, PB 312, PB 314, PB 324, PB 346, PB 350, PB 355, IAC 56, IAC 302, IAC 328, IAC 334, Fx 3899 and RRIM 600. The evaluation of C. heveae and T. heveae populations was performed by counting mites and exuviae presence in six leaflets per plot. The defoliation levels were evaluated with a score scale, varying from 0 (no defoliation) to 4 (above 75% of defoliation). Based on the results, Fx 3899 clone is resistant through non-preference and/or antibiosis to C. heveae. The IAC 56 clone is less susceptible to defoliation caused by C. heveae and T. heveae infestation.

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

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Brazilian southeastern region has soil and climate conditions suitable for the growing of rubber trees, and most part of national yield arises from São Paulo State. The aims proposed for this work were to determine the diversity, the richness and the seasonal occurrence of mites found in a rubber tree crop in a triennial survey with monthly samplings, as well as to estimate the populational density of the major phytophagous species. This study found 74,407 mites from 26 species belonging to 10 families. The phytophagous and predators represented 95.4% and 3.9% of the total abundance, respectively. Twelve species were rare, six accessories and eight constant. The families Phytoseiidae and Tydeidae had the greatest richness (five and four species, respectively). The most numerous species was Calacarus heveae Feres (50,573), with great abundance at the end of rainy season until the beginning of dry season. Among predators, the most abundant were Zetzellia quasagistemas Hernandes & Feres (1,345), Pronematus sp. (455), Zetzellia agistzellia Hernandes & Feres (409) and Euseius citrifolius Denmark & Muma (243). C. heveae had greatest densities on March and April 2003, and Lorryia formosa Cooreman and Tenuipalpus heveae Baker on March and May 2001, respectively. Many stigmaeids were observed in association with colonies of L. formosa preying their eggs and immatures.

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A Região Sudeste do Brasil apresenta aspectos edafo-climáticos favoráveis para o plantio e desenvolvimento da seringueira, sendo o estado de São Paulo o maior produtor nacional de látex. Este trabalho teve como objetivos determinar, através de coletas mensais durante três anos de estudo, a diversidade, a riqueza de espécies e a sua sazonalidade, bem como realizar estimativas de densidade populacional das principais espécies de ácaros presentes nas folhas. Todos os ácaros foram montados em lâminas de microscopia, totalizando 74.407 indivíduos, de 26 espécies pertencentes a 10 famílias. Os fitófagos representaram 95,4% do total de indivíduos coletados e os predadores 3,9%. Doze espécies foram consideradas acidentais, seis foram acessórias e oito constantes. Apresentaram maior número de espécies as famílias Phytoseiidae (cinco) e Tydeidae (quatro). A espécie mais abundante foi Calacarus heveae Feres (50.573), com maior abundância nos meses correspondentes ao término da estação chuvosa e início da estação seca na região. Dentre os predadores, a mais abundante foi Zetzellia quasagistemas Hernandes & Feres (1.345), seguida por Pronematus sp. (455), Zetzellia agistzellia Hernandes & Feres (409) e Euseius citrifolius Denmark & Muma (243). C. heveae apresentou maior densidade populacional em março e abril de 2003, e Lorryia formosa Cooreman e Tenuipalpus heveae Baker em março e maio de 2001, respectivamente. Muitos estigmeídeos foram observados associados a agrupamentos de L. formosa predando seus ovos e estágios imaturos.

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Pós-graduação em Agronomia - FEIS

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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La caléndula (Calendula officinalis) es una planta herbácea utilizada por sus hermosas flores amarillas o naranjas en borduras, jardinería y como flor de corte. Está ampliamente difundida en el mundo, no sólo por la belleza de sus flores o por su uso en la cosmética sino por ser resistente, de fácil cultivo y poco exigente en condiciones ambientales. En Mendoza es muy empleada como ornamental y todos los años es afectada por una enfermedad denominada oídio. En Argentina se mencionan como agentes etiológicos del oídio diversas especies del género Erysiphe y Oidium erysiphoides, pero no se había descripto la forma teleomórfica sino hasta 1991 en Corrientes y Córdoba, cuando fue citada como Sphaerotheca fusca. En 2004, en Mendoza, se produjo un intenso ataque de oídio sobre esta especie floral y al estudiar la pulverulencia típica de la enfermedad se observaron cuerpos negros, lo que motivó el estudio etiológico de la enfermedad en dicha provincia. Se muestrearon ejemplares de caléndula afectados procedentes de distintos orígenes. En laboratorio se realizaron observaciones y estudios morfométricos que permitieron reconocer Podosphaera fusca (=Sphaerotheca fusca) como agente responsable del oídio de la caléndula en Mendoza.

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[Cont.] The grape leaf-hopper (Bulletin no.198), by H. J. Quayle, 1908 -- Selection from Imperial Valley settlers' crop manual (pp.193-212) (Bulletin no.210), 1911?

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Agricultural crops can be damaged by funguses, insects, worms and other organisms that cause diseases and decrease the yield of production. The effect of these damaging agents can be reduced using pesticides. Among them, triazole compounds are effective substances against fungus; for example, Oidium. Nevertheless, it has been detected that the residues of these fungicides in foods as well as in derivate products can affect the health of the consumers. Therefore, the European Union has established several regulations fixing the maximum residue of pesticide levels in a wide range of foods trying to assure the consumer safety. Hence, it is very important to develop adequate methods to determine these pesticide compounds. In most cases, gas or liquid chromatographic (GC, LC) separations are used in the analysis of the samples. But firstly, it is necessary to use proper sample treatments in order to preconcentrate and isolate the target analytes. To reach this aim, microextraction techniques are very effective tools; because allow to do both preconcentration and extraction of the analytes in one simple step that considerably reduces the source of errors. With these objectives, two remarkable techniques have been widely used during the last years: solid phase microextraction (SPME) and liquid phase microextraction (LPME) with its different options. Both techniques that avoid the use or reduce the amount of toxic solvents are convenient coupled to chromatographic equipments providing good quantitative results in a wide number of matrices and compounds. In this work simple and reliable methods have been developed using SPME and ultrasound assisted emulsification microextraction (USAEME) coupled to GC or LC for triazole fungicides determination. The proposed methods allow confidently determine triazole concentrations of μg L‐1 order in different fruit samples. Chemometric tools have been used to accomplish successful determinations. Firstly, in the selection and optimization of the variables involved in the microextraction processes; and secondly, to overcome the problems related to the overlapping peaks. Different fractional factorial designs have been used for the screening of the experimental variables; and central composite designs have been carried out to get the best experimental conditions. Trying to solve the overlapping peak problems multivariate calibration methods have been used. Parallel Factor Analysis 2 (PARAFAC2), Multivariate Curve Resolution (MCR) and Parallel Factor Analysis with Linear Dependencies (PARALIND) have been proposed, the adequate algorithms have been used according to data characteristics, and the results have been compared. Because its occurrence in Basque Country and its relevance in the production of cider and txakoli regional wines the grape and apple samples were selected. These crops are often treated with triazole compounds trying to solve the problems caused by the funguses. The peel and pulp from grape and apple, their juices and some commercial products such as musts, juice and cider have been analysed showing the adequacy of the developed methods for the triazole determination in this kind of fruit samples.