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Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 147-157). Available also in a digital version from Dissertation Abstracts.

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The boll weevil (Anthonomus grandis grandis Boheman) is currently under eradication in the U.S. The eradication program is implemented by means of area-wide applications of malathion ULV. Frequent applications of this insecticide result in high mortality of many beneficial insects, and a greater risk of secondary pest outbreaks. Notable among the latter are the outbreaks of beet armyworm (Spodoptera exigua H?bner) and cotton aphid (Aphis gossypii Glover) in the Lower Rio Grande Valley in 1995. The present study (i) compared densities of beneficial and pest insect and spider populations between cotton fields in eradication and non-eradication areas; (ii) evaluated the use of beneficial cotton arthropod population densities as indicators of pest damage risks from cotton aphid, beet armyworm, bollworm (Helicoverpa zea Boddie), and other worms (Estigmene acrea Drury, Pseudoplusia includens Walker, and Trichoplusia ni H?bner); and (iii) evaluated the effects of malathion ULV on the red imported fire ant (Solenopsis invicta Buren) a key arthropod predator in cotton agroecosystems. Studies were conducted in central Texas, in the vicinities of College Station and Dallas, during 2002 and 2003. Results showed that a majority of cotton predators were negatively impacted by malathion ULV applications. However, convergent lady beetle (Hippodamia convergens Gu?rin-M?neville) densities were greater in active eradication fields than inactive fields. Stepwise regression analyses identified densities of lacewing (Chrysoperla carnea Stephens) larvae and lady beetle larvae (H. convergens, Coleomegilla maculata De Geer, Harmonia axyridis Pallas, and Coccinella septempunctata L.) as predictors of cotton aphid density, and density of total spiders as predictors of bollworm density. Predictors of beet armyworm or other worm densities could not be determined. This study demonstrated malathion ULV was highly toxic to fire ants, and could repel ants from treated surfaces. Malathion ULV reduced the number of foraging fire ants in the cotton canopy for three weeks and reduced fire ant predation of beet armyworm eggs. Predictors of secondary pest densities have been suggested which, if utilized, may help to prevent the occurrence of secondary pest outbreaks under boll weevil eradication. Validation of these predictors should be preformed before implementing them into an eradication program.

This dissertation studies three institutions of development in the United States during the early twentieth century. The first chapter exploits a unique shift in agricultural production in the American South to analyze how the cultivation of a child labor intensive crop (cotton) impacted schooling, with a particular focus on racial differences. Since African-American children were more likely to be employed as farm laborers than white children, their educational attainment may have been more responsive to changes in cotton production. I test this prediction using newly collected county-level panel data for Georgia, a major cotton producer. The results reveal that reductions in cotton production increased the school enrollment rate of African Americans. By contrast, I find little evidence that cotton production affected the enrollment rate of whites. This suggests that the shift away from cotton production after the arrival of the boll weevil can explain a significant amount of the narrowing of the racial differential in enrollment rates. The second chapter explores how Southern school boards responded to changes in their budgetary environment. I utilize exogenous variation in state school funds generated by discontinuous budget allocation rules, and employ a differences-in-differences strategy, to investigate how the relative quality of education for African Americans changed with the level of state funding for education. Results suggest whites, rather than African Americans, bore the brunt of budget cuts, perhaps because there was little fat to trim from the budgets of African-American schools. The third chapter of this dissertation (co-authored with Carola Frydman and Eric Hilt) estimates the effect of President McKinley's assassination on corporate valuations. McKinley acted favorably toward business interests, and while in office he permitted significant merger activity. His Vice President, Theodore Roosevelt, was a well known reformer and took a stronger stance against trusts. Our analysis indicates that firms vulnerable to antitrust prosecution saw greater decreases in their valuations following the assassination. The value of railroads susceptible to antitrust litigation declined further when Roosevelt sought to apply the Sherman Act to railroads, providing further evidence that firms benefited from regulatory forbearance during McKinley's Presidency.

Made available in DSpace on 2016-03-07T19:20:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-10-01. Added 1 bitstream(s) on 2016-03-07T19:24:06Z : No. of bitstreams: 1 000858038.pdf: 2029297 bytes, checksum: 32eca951c39a9154e19ceffc8c5311f5 (MD5) / O bicudo-do-algodoeiro, Anthonomus grandis, é a principal praga da cotonicultura mundial e o conhecimento de sua bioecologia e distribuição na cultura é indispensável para realizar amostragens e determinar o momento adequado de seu controle. O objetivo deste trabalho foi estudar a dinâmica populacional, a distribuição vertical e espacial de A. grandis, bem como elaborar um plano de amostragem sequencial para essa praga. Os experimentos foram conduzidos nos anos agrícolas 2012/13 e 2013/14, na Estação Experimental da Fundação MS, em Maracaju, MS, em um campo de 10.000 m2, subdividido em 100 parcelas de 10 x 10 m. A cultivar utilizada foi FM 993, semeada com 80 cm de espaçamento entrelinha. Para a condução da cultura foram utilizados fungicidas, herbicidas e o regulador de crescimento, exceto inseticidas. Semanalmente foram avaliadas cinco plantas por parcela e registrou-se o número de botões florais com orifícios de alimentação, oviposição e de adultos de A. grandis em cada estrato das plantas (terço superior, médio e inferior). Para o estudo da dispersão da praga na área, foram utilizados os índices: razão variância/média, índice de Morisita, Coeficiente de Green e expoente k da distribuição Binomial Negativa. Para estudo dos modelos probabilísticos que descrevem a distribuição espacial dos insetos, foram testados os ajustes às distribuições de Poisson e Binomial Negativa. O plano de amostragem sequencial foi elaborado com base no Teste Sequencial da Razão da Máxima Verossimilhança, e foi utilizado o nível de controle de 10% dos botões florais atacados (alimentação + oviposição) e o nível de segurança de 5% de botões florais atacados (alimentação + oviposição). O valor do erro tipo I e do erro tipo II utilizado foi 0,05, o mais indicado para estudos com insetos. A distribuição espacial dos botões florais utilizados para alimentação e para oviposição foi de forma agregada até... / The cotton boll weevil Anthonomus grandis is the main pest of cotton crop worldwide, and the knowledge of its bioecology and distribution is essential to carry out sampling and determine the right time of your control. The main purpose of this study was to evaluate the population dynamics, vertical and spatial distribution of A. grandis and prepare a sequential sampling plan for this pest. The experiments were conducted in two seasons, 2012/13 and 2013/14, at the Experimental Station of the Foundation MS, in Maracaju, MS, in a field of 10,000 m2, divided into 100 plots of 10 x 10 m. The cultivar used was FM 993, seeded 80 cm rows apart. For the crop development were used fungicides, herbicides and growth regulators, except insecticides. Five plants per plot were weekly evaluated and recorded the number of flower buds with feeding and oviposition punctures, and adults of A. grandis in each part of five plants (upper, middle and lower). To dispersion study of A. grandis in the area, the following indexes were used: variance/mean ration, Morisita index, Green coefficient and k exponent of negative binomial distribution. To study the probabilistic models that describes the spatial distribution of insects, adjustments to Poisson and Negative Binomial distributions were tested. The sequential sampling plan was based on Maximum Likelihood Reason Sequential Test, and used the threshold level of 10% of attacked flower buds (feeding + oviposition) and the security level of 5% of attacked flower buds (feeding + oviposition). The values of type I and type II errors used was 0.05, the most suitable for insect studies. The spatial distribution of flower buds with feeding and oviposition was aggregate up to 85 DAE, with best fit to the Negative Binomial distribution, and as of this date was random, with best fit to the Poisson distribution. Adults of A. grandis are randomly distributed in the area, with best fit to Poisson distribution throughout ...

Orientador: Antonio Carlos Busoli / Coorientador: Marcos Gino Fernandes / Banca: José Carlos Barbosa / Banca: Raphael de Campos Castilho / Banca: Marcos Doniseti Michelotto / Banca: Crébio José Ávila / Resumo: O bicudo-do-algodoeiro, Anthonomus grandis, é a principal praga da cotonicultura mundial e o conhecimento de sua bioecologia e distribuição na cultura é indispensável para realizar amostragens e determinar o momento adequado de seu controle. O objetivo deste trabalho foi estudar a dinâmica populacional, a distribuição vertical e espacial de A. grandis, bem como elaborar um plano de amostragem sequencial para essa praga. Os experimentos foram conduzidos nos anos agrícolas 2012/13 e 2013/14, na Estação Experimental da Fundação MS, em Maracaju, MS, em um campo de 10.000 m2, subdividido em 100 parcelas de 10 x 10 m. A cultivar utilizada foi FM 993, semeada com 80 cm de espaçamento entrelinha. Para a condução da cultura foram utilizados fungicidas, herbicidas e o regulador de crescimento, exceto inseticidas. Semanalmente foram avaliadas cinco plantas por parcela e registrou-se o número de botões florais com orifícios de alimentação, oviposição e de adultos de A. grandis em cada estrato das plantas (terço superior, médio e inferior). Para o estudo da dispersão da praga na área, foram utilizados os índices: razão variância/média, índice de Morisita, Coeficiente de Green e expoente k da distribuição Binomial Negativa. Para estudo dos modelos probabilísticos que descrevem a distribuição espacial dos insetos, foram testados os ajustes às distribuições de Poisson e Binomial Negativa. O plano de amostragem sequencial foi elaborado com base no Teste Sequencial da Razão da Máxima Verossimilhança, e foi utilizado o nível de controle de 10% dos botões florais atacados (alimentação + oviposição) e o nível de segurança de 5% de botões florais atacados (alimentação + oviposição). O valor do erro tipo I e do erro tipo II utilizado foi 0,05, o mais indicado para estudos com insetos. A distribuição espacial dos botões florais utilizados para alimentação e para oviposição foi de forma agregada até... / Abstract: The cotton boll weevil Anthonomus grandis is the main pest of cotton crop worldwide, and the knowledge of its bioecology and distribution is essential to carry out sampling and determine the right time of your control. The main purpose of this study was to evaluate the population dynamics, vertical and spatial distribution of A. grandis and prepare a sequential sampling plan for this pest. The experiments were conducted in two seasons, 2012/13 and 2013/14, at the Experimental Station of the Foundation MS, in Maracaju, MS, in a field of 10,000 m2, divided into 100 plots of 10 x 10 m. The cultivar used was FM 993, seeded 80 cm rows apart. For the crop development were used fungicides, herbicides and growth regulators, except insecticides. Five plants per plot were weekly evaluated and recorded the number of flower buds with feeding and oviposition punctures, and adults of A. grandis in each part of five plants (upper, middle and lower). To dispersion study of A. grandis in the area, the following indexes were used: variance/mean ration, Morisita index, Green coefficient and k exponent of negative binomial distribution. To study the probabilistic models that describes the spatial distribution of insects, adjustments to Poisson and Negative Binomial distributions were tested. The sequential sampling plan was based on Maximum Likelihood Reason Sequential Test, and used the threshold level of 10% of attacked flower buds (feeding + oviposition) and the security level of 5% of attacked flower buds (feeding + oviposition). The values of type I and type II errors used was 0.05, the most suitable for insect studies. The spatial distribution of flower buds with feeding and oviposition was aggregate up to 85 DAE, with best fit to the Negative Binomial distribution, and as of this date was random, with best fit to the Poisson distribution. Adults of A. grandis are randomly distributed in the area, with best fit to Poisson distribution throughout ... / Doutor

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Made available in DSpace on 2014-06-11T19:26:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-07Bitstream added on 2014-06-13T19:25:31Z : No. of bitstreams: 1 alves_mc_me_jabo.pdf: 784728 bytes, checksum: a9d8c2237ee21059f774f2a73b627b7f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O controle biológico utilizando microrganismos vem sendo estudado como uma alternativa ao uso de agroquímicos. Estes pesticidas poluem o ambiente, além de serem tóxicos a diversas espécies vegetais e animais. Diante disso, a bactéria Bacillus thuringiensis é um importante entomopatógeno que vem sendo utilizado na agricultura pelo fato de secretar proteínas que são tóxicas a insetos pertencentes a diversas ordens. Dentre os diversos genes de B. thuringiensis que codificam proteínas tóxicas, as classes vip1, vip2 e cry3 destacam-se como alternativa para o controle de insetos-praga da ordem Coleoptera. O presente trabalho objetivou a identificação e caracterização molecular, por meio da técnica de PCR-RFLP, dos genes cry3, vip1, vip2 e vip1/vip2 em uma coleção de B. thuringiensis, quanto a possíveis polimorfismos existentes, procurando relacioná-los à toxicidade em larvas de Anthonomus grandis. Da análise de 1078 isolados de B. thuringiensis, foram encontrados 151 isolados positivos para os genes em estudo e 14 perfis polimórficos, indicando a presença de subclasses destes genes. Os resultados obtidos nos ensaios de toxicidade indicam que os polimorfismos gênicos podem apresentar interferência na toxicidade das proteínas, sendo que a toxina Cry3 apresentou uma maior efetividade na mortalidade em larvas de A. grandis. Os resultados também evidenciaram que a PCR-RFLP mostrou-se apropriada para a detecção da variabilidade genética em B. thuringiensis, permitindo a identificação de haplótipos / Biological control using microorganisms is being studied as an alternative to the use of agrochemicals. These pesticides pollute the environment, being toxic to many species of plants and animals. For these reasons, the bacterium Bacillus thuringiensis is an important entomopathogen that has been used in agriculture, once it produces proteins that are toxic to many target insect orders. Among several genes from B. thuringiensis that encode toxic proteins there are vip1, vip2 and cry3 classes that stand as an alternative for controlling insect pests belonging the Coleoptera order. The objective of this work was to identify and characterize molecularly, through PCR-RFLP, the genes cry3, vip1, vip2 and vip1/vip2 in a collection of B. thuringiensis, for possible polymorphisms exist, trying to relate them to the toxicity in Anthonomus grandis larvae. Analysis of 1078 isolates of B. thuringiensis, were found 151 positive isolates for the genes under study and 10 polymorphic profiles, which indicate the presence of subclasses of the genes. These results obtained in tests toxicity indicate that polymorphisms gene may have interference with the toxicity of the protein, and the toxin Cry3 showed a greater effectiveness in mortality in A. grandis larvae. These results also showed that the PCR-RFLP proved to be suitable for the detection of genetic variability in B. thuringiensis, allowing the identification of haplotypes