Índice de infestação e fatores de mortalidade do bicudo-do-algodoeiro (Coleoptera: Curculionidae) no semi-árido do sudoeste da Bahia, Brasil

The boll weevil (Anthonomus grandis Boheman, 1843) (Coleoptera: Curculionidae) is a pest that limits the production of cotton, especially in the North East of Brazil. The present study aimed to estimate the infestation index and natural mortality of boll weevil at Caraibas County, located in the semi-arid of the Southwest ofBahia. The experiment was performed using the cultivar BSR Aroeira, at Fazenda Lagoa Seca, in 2006. Weekly evaluations were performed, in five sampling areas 25m2, collecting blossoms fallen on the ground. The infestation was estimated by counting the oviposition punctures and /or the feeding on blossoms, and also by the presence of one of the phases of the boll weevil in the inside. Mortality factors were studied through the dissection of blossoms, estimating predation, parasitism, dissection and disease. The results obtained allowed to conclude that the boll weevil determines high infestation levels in the region. Parasitism, dissection and predation, following this order, determine high rates of real mortality of the pest. Catolaccus grandis Burks, 1954 (Hymenoptera: Pteromalidae) and Bracon sp.(Hymenoptera: Braconidae) are parasitoids of boll weevil reported in sothwestern Bahia, being the first one the predominant species. © 2009, Sociedad Venezolana de Entomología.

Umedecimento e substratos para germinação de sementes de repolho

The availability of water for seeds is closely related to their germination, since hydration is a limiting factor for their metabolic processes. Therefore, in tests carried out in laboratory, substrate must be sufficiently moistened, in order to assure both the embryo growth and seedling formation. This research was carried out to evaluate the influence of different quantities of water, in different substrates, for cabbage (Brassica oleracea var. capitata) seeds germination. The seeds, processed with Thiran 0.1%, were obtained in shops located in Jaboticabal, São Paulo State, Brazil. Germination tests were made in germitest rolled paper towel substrates, between and on draft paper, moistened with quantities of water equivalent to 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; and 4.0 times the dry substrate weight. For each treatment, four repetitions of 50 seeds were used. The seeds were kept in a germinator, at an alternate temperature of 20-30°C, without further addition of water to the substrate. The evaluations were made on the fifth and tenth days after the experiment preparation. The results obtained revealed that the quantities of water ranging from 1.5 to 2.5 times the paper weight were favorable for seeds germination, mainly in the substrate on and between the paper, while water levels above 3.0 times the substrate weight were harmful for cabbage seeds germination in the rolled paper towel substrates and between the paper.

La viabilidad de la construcción de un índice sintético de cohesión social para América Latina

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Metodología y estimación del índice de producción industrial de Jujuy. Un aporte a la cuantificación de los objetivos de desarrollo del milenio

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Metodología y estimación del índice de producción industrial de Salta: un aporte a la cuantificación de los objetivos de desarrollo del milenio

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América Latina: evolución del índice de precios de los principales productos de exportación, 1960-2010

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El índice combinado de condición étnica lingüística (CEL) y su aplicación al Censo 2001 de Bolivia

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Consideraciones sobre el índice de Gini para medir la concentración del ingreso

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Determinação do índice de estresse hídrico em cultura do feijoeiro com termômetro de infravermelho

In order to calculate the daily stress degree of a bean crop submitted to four water regime applications, cover crop and air daily measurements temperatures were accomplished by using a hand-held infrared thermometer. The treatments did not present crop water stress except the control (without irrigation). The highest yield was obtained by the treatment that received less irrigation frequency, and among the treatments that had the same number of irrigation. The largest yield was obtained with the one that received larger amount of applied water. The largest irrigation frequency did not result in larger productivity. The methodologies used for the irrigation planning were efficient for the replacement of soil water. The daily stress degree index was effective in determining crop water stress; and it was reliable presenting negative values in good water soil condition.

Sementes de feijão-caupi (Vigna unguiculata L. (Walp), tratadas com extrato de folhas de nim (Azadirachta indica A. Juss.) avaliação da germinação e da incidência de fungos

This study aimed to evaluate the effect of aqueous extract of neem on germination and fungi incidence on seeds of three cultivars (Serrinha, BR 17 and Maranhão) of cowpea. Neem leaves were dryed, crushed and prepared dilutions of 0.5; 1.0; 2.0, 4.0 g dm -3and control. The fungi incidence was evaluated by the test filter paper and germination according to the Rules for Seeds Testing (Regras para Análise de Sementes). In the three cultivars analyzed, reduction in the incidence of Aspergillus sp and Fusarium sp was observed. In relation to the influence of extracts of neem leaves on seed germination, significant effect of extract in Maranhão cultivar was observed, where all concentrations differed from the control, and propovided a considerable increase in the percentage of normal seedlings. It was concluded that the leaf extract of neem was effective in controlling Aspergillus sp, Fusarium sp , Phoma sp and Macrophomina phaseolina at different concentrations in different cultivars and seed germination was stimulated for the Maranhão cultivar.

Superação de dormência e influência dos fatores ambientais na germinação de sementes de Spermacoce latifolia

Understanding basic information on weed biology contributes to the implementation of appropriate management and control strategies. Thus, this work was developed to evaluate the germination of Spermacoce latifolia Aubl. seeds, an important weed in reforestation areas. The seeds were subjected to dormancy break treatments, in which the mechanical scarification, chemical treatment (H2SO 4 and KNO 3), heat treatment, and control, were evaluated. Three more tests were done determinate the effects of temperature (10, 15, 20, 25, 30 and 35°C), light filters (absence of light and red, green, yellow, distant red, blue, orange and clear light) and water availability (0.0, -0.2, -0.4, -0.6, -0.8 and -1.0 MPa) on the seeds germination and vigor. The treatments were arranged in a completely randomized design with four replications, and the experimental plot was constituted by gerbox plastic boxes with 50 seeds. The mechanical scarification (sanding) provided the best dormancy break, indicating that Spermacoce latifolia seeds have tegument water impermeability. The seeds showed higher germination percentage under conditions of mild water stress (-0.2 MPa) and the optimal temperature was 25°C. The blue light reduced seed germination.

Metodologia para análise da dependência térmica da germinação pelo modelo de grausdia

The effects of temperature on the rate of biological processes such as the germination are reported in several papers. The analysis of the thermal effect can be performed either from numerical indices or germination curves, which is usually presented as the accumulated percentage of germination versus time. Such curves can be fitted by empirical models and generally they offer a better description of the time-course of germination than single-value indices. On the other hand, in analyzing the germination curves, a question arises whether the model parameters have biological meaning. Thus, it is desirable that the model parameters both describe properly the germination curve and have biological meaning, which often does not occur. Considering the involvement of populations and percentages in germination assays, an analytical model has been widely used in the last two decades which is based on the concept of thermal time. This article discusses the conceptual basis and provides procedures for applying the thermal-time model in germination studies by using the probit regression method, both at infra and supra-optimal temperatures.

Instrumentos para la toma de decisiones en políticas de seguridad vial en América Latina: el índice de seguridad de tránsito (INSETRA)

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