598 resultados para insecticides


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The objective of this work was to evaluate the energy and economic efficiency indexes per unit of cotton agro-ecosystem area in family production systems of Paraguay and Brazil; and, to establish a relationship between the energy and economic. Typologies presented by the Program to Support Small Cotton Holdings (Paraguay), and by the National Program for Strengthening Family Agriculture (Brazil). Family systems of the two countries were identified; these are located from Paraguay (San Juan–CA) and from Brazil (Leme–SP). To construct the energy expenditure structure of the cotton agro-ecosystem, as well as to assess the economic efficiency, the mean values obtained were considered, when they presented similarities in production systems and they were within the typology proposed in this study. From the technical itinerary observed the Paraguayan agro-ecosystem depended (fossil fuel 56.76%) and industrial source (35.99%). Thus, the energy balance of the agricultural stage was established, which attained a value of 17,740.69 MJ ha-1; an energy efficiency of 5.28, and a cultural efficiency of 3.04. The Brazilian agro-ecosystem depended on energy from industrial source (insecticides 39.82%) and from fossil fuel (33.59%); it reached an energy balance of 19,547.88 MJ ha-1; an energy efficiency of 2.12, and a cultural efficiency index of 0.71. In the economic and energy indicator ratio, with regard to the months referring to the harvest time, that is to say, March, April, and May, the maximum economic efficiency indicator of paraguay was attained in the month of May (1,00), and from Brazil in the month of May (1,71). Both production systems analyzed were presented efficient, however, dependent of external circumstances and non-renewable energy sources.

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The objective of this work was to evaluate the energy and economic efficiency indexes per unit of cotton agro-ecosystem area in family production systems of Paraguay and Brazil; and, to establish a relationship between the energy and economic. Typologies presented by the Program to Support Small Cotton Holdings (Paraguay), and by the National Program for Strengthening Family Agriculture (Brazil). Family systems of the two countries were identified; these are located from Paraguay (San Juan–CA) and from Brazil (Leme–SP). To construct the energy expenditure structure of the cotton agro-ecosystem, as well as to assess the economic efficiency, the mean values obtained were considered, when they presented similarities in production systems and they were within the typology proposed in this study. From the technical itinerary observed the Paraguayan agro-ecosystem depended (fossil fuel 56.76%) and industrial source (35.99%). Thus, the energy balance of the agricultural stage was established, which attained a value of 17,740.69 MJ ha-1; an energy efficiency of 5.28, and a cultural efficiency of 3.04. The Brazilian agro-ecosystem depended on energy from industrial source (insecticides 39.82%) and from fossil fuel (33.59%); it reached an energy balance of 19,547.88 MJ ha-1; an energy efficiency of 2.12, and a cultural efficiency index of 0.71. In the economic and energy indicator ratio, with regard to the months referring to the harvest time, that is to say, March, April, and May, the maximum economic efficiency indicator of paraguay was attained in the month of May (1,00), and from Brazil in the month of May (1,71). Both production systems analyzed were presented efficient, however, dependent of external circumstances and non-renewable energy sources.

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One of the arguments for the rapid adoption of genetically modified (GM0 corn in Brazil is the economic advantage that this technology can offer. Given that its benefits and gains are subject to the conditions of modifications of critical variables, the present work aimed to estimate the economic returns of Bt (Bacillus thuringiensis) corn by analyzing variations in quantities and prices of insecticides used, productivity gains, the price of using GM seed compared with non-GM seed, as well as changes in corn prices. It was concluded that the GM technology generated net economic gains of US$ 235.50/ha.

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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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The soybean (Glycine max) is of great importance to national economic scenario being a major Brazilian agribusiness products. In most regions, the caterpillar-of-soy (Anticarsia gemmatalis) and caterpillar-false-Medideira (Pseudoplusia includes), act as defoliators, with the highest incidence, usually during the growing season, until the end of flowering, and thus causing a significant reduction in the production, which requires control measures. Due to market demands and the large external environmental awareness exists today, the methods of ecological management have been highlighted in modern agriculture. The use of chemical insecticides, besides being harmful to the environment and man, is, in most cases, the high cost to the farmer. The biological pest control using natural enemies can be used as an alternative control method. Thus this literature review is intended to provide the updated information about these pests and biological control as an alternative form of control, as well as one more tool in the integrated pest of soybean.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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We live in a world of chemicals. Unfortunately, some of the characteristics that make household chemical products the most useful are the same qualities that lead to trouble when these products are carelessly handled. A chemical stain or spot is a serious kind of stain that is appearing with increasing frequency and is different from ordinary stains. This type of discoloration or color is caused by a variety of chemical ingredients contains in dozens of common household products. This NebFact discusses the different chemical spots, stains and discolorations that are found in your home furnishings.

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This NebGuide describes the life cycle of the army cutworm and pale western cutworm, and provides recommendations for management.The army cutworm, Euxoa auxiliaris, and the pale western cutworm, Agrotis orthogonia, are sporadic pests that are distributed throughout the Great Plains. The army cutworm can be found throughout Nebraska, but is more common in the western half of the state. Because of the drier environment, the pale western cutworm is found only in the western third of Nebraska. Both cutworms can feed on a vast array of crops and weeds. Their major economic impact is limited to winter wheat and alfalfa, because these are the vulnerable crops growing in the early spring when larval feeding activity occurs. However, they can also cause substantial damage to early spring row crops (sugarbeets and corn), especially in areas where winter cereal cover crops are used.

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This NebGuide describes the two common spider mites found in Nebraska corn and soybeans, their natural enemies and management. Two species of spider mites, the Banks grass mite and twospotted spider mite, commonly feed on Nebraska corn. Banks grass mites (BGM) feed almost exclusively on grasses, including corn and sorghum. Twospotted spider mites (TSM) not only feed on many species of grasses, but also on soybeans, fruit trees and a variety of vegetables and ornamental plants. Although these two species are somewhat similar in appearance, they differ in several biological characteristics and in their susceptibility to pesticides. Banks grass mites usually appear earlier in the season, feed mostly on the lower leaves of the corn plant, and in Nebraska are moderately susceptible to many of the commonly used miticides. On the other hand, TSM tend to appear in mid to late season, increase rapidly, feed over the entire plant, and often are not consistently controlled by available pesticides.

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The larvicidal activity of the neotropical "matico" Piper tuberculatum was evaluated. The secondary compounds were extracted of leaves, stems and mature spikes with fruits and seeds from wild plants and in vitro plants of Piper tuberculatum. The acute toxicities to the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), of extracts of spikes with fruits and seeds and in vitro plants of P tuberculatum were evaluated by means of contact bioassays. Only CH2Cl2:MeOH (2:1) and EtOH extracts of mature spikes and CH2C12:MeOH (2:1) extract from in vitro plants showed significant levels of larval mortality. The CH2Cl2:MeOH (2:1) and EtOH extracts of mature spikes caused 90% mortality when doses of 0.1850 mg/mu L were applied to the S. frugiperda in 24 and 48 h of exposure, respectively. The CH2Cl2:MeOH (2:1) extract from in vitro plants caused 95% mortality when doses of 0.1850 mg/mu L were too applied in 48 h of exposure. The mature spikes test best results were: LD50 0.001 mg/mu L with EtOH and 0.007 mg/mu L with CH2Cl2:MeOH (2:1) and LD90 0.027 mg/mu L with EtOH and 0.103 mg/mu L with CH2Cl2:MeOH (2:1); and, in the case of in vitro plants, only CH2Cl2:MeOH (2:1) extract was: LD50 0.003 mg/mu L and LD90 0.060 mg/mu L. The potential value of extracts derived from P. tuberculatum as efficient insecticides against S.frugiperda is discussed.

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The banana weevil Cosmopolites sordidus (Germar) is one of a number of pests that attack banana crops. The use of the entomopathogenic fungus Beauveria bassiana as a biological control agent for this pest may contribute towards reducing the application of chemical insecticides on banana crops. In this study, the genetic variability of a collection of Brazilian isolates of B. bassiana was evaluated. Samples were obtained from various geographic regions of Brazil, and from different hosts of the Curculionidae family. Based on the DNA fingerprints generated by RAPD and AFLP, we found that 92 and 88 % of the loci were polymorphic, respectively. The B. bassiana isolates were attributed to two genotypic clusters based on the RAPD data, and to three genotypic clusters, when analyzed with AFLP. The nucleotide sequences of nuclear ribosomal DNA intergenic spacers confirmed that all isolates are in fact B. bassiana. Analysis of molecular variance showed that variability among the isolates was not correlated with geographic origin or hosts. A RAPD-specific marker for isolate CG 1024, which is highly virulent to C. sordidus, was cloned and sequenced. Based on the sequences obtained, specific PCR primers BbasCG1024F (5'-TGC GGC TGA GGA GGA CT-3') and BbasCG1024R (5'-TGC GGC TGA GTG TAG AAC-3') were designed for detecting and monitoring this isolate in the field.

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The use of insecticide plants is an important tool in the management of insect pests. Aiming to control Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), neem nanoformulations were evaluated. After estimating the LC50 for a commercial neem oil formulation, selection bioassays were performed with 22 nanoformulations. In order to do that, newly emerged caterpillars were fed on leaflets treated with nanoformulation solutions for 10 days. The effect on the development and longevity of the insect was evaluated with the two most promising nanoformulations, aqueous NC40 and powdered NC40 (NC 40 = Poly- -hydroxibutirate nanocapsules). The LC50 for neem oil was estimated in 0.20% or 1.31mgL(-1) of azadiractin. The nanoformulations aqueous NC40 and powdered NC40 affected the insect development.