Submitted by Ana Paula Lisboa Monteiro (monteiro@univates.br) on 2012-05-23T17:25:20Z No. of bitstreams: 3 ClovisSchwertner.pdf: 2827006 bytes, checksum: eb7b2183e0587c3616a46b69da2aefcd (MD5) license_rdf: 22192 bytes, checksum: 16508d913bcfe515c0f9e2bdf06ca16d (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2012-05-23T17:25:20Z (GMT). No. of bitstreams: 3 ClovisSchwertner.pdf: 2827006 bytes, checksum: eb7b2183e0587c3616a46b69da2aefcd (MD5) license_rdf: 22192 bytes, checksum: 16508d913bcfe515c0f9e2bdf06ca16d (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / No Brasil o cultivo de plantas ornamentais aumentou nas últimas três décadas, tornando-se uma importante atividade econômica do agronegócio. No mercado nacional, o Rio Grande do Sul é o segundo maior produtor de flores e plantas cultivadas e o maior consumidor. Dentre as espécies mais cultivadas, as gérberas (Gerbera jamesonii Adlam), nos Vales do Taquari, Caí e Rio Pardo predominam. Quanto à ocorrência de ácaros, o ácaro rajado (Tetranychus urticae Koch, 1836: Tetranychidae) na cultura de gérberas em estufa, prejudica a qualidade e beleza da flor causando danos econômicos. O uso de agrotóxicos para a eliminação de pragas diversas, elimina também os inimigos naturais destes, e a constante aplicação destes agrotóxicos tornam os insetos fitófagos resistentes. Demonstrou-se que os produtos naturais e biológicos são uma alternativa eficiente para o controle do ácaro rajado na cultura de gérberas. Entre os produtos naturais e biológicos testados (Beauveria bassiana e Metarhizium anisopliae, Azadiractina, e calda sulfocálcica à base de enxofre e cálcio) e o agrotóxico de referência (à base de Abamectina) todos estes foram eficientes para o controle do ácaro rajado. Porém, os produtos naturais e biológicos preservaram em sua maioria os inimigos naturais, não agrediram o meio ambiente, ao passo que o agrotóxico eliminou totalmente os inimigos naturais além de seu efeito ser persistente e perigoso ao meio ambiente.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-15T11:31:33Z No. of bitstreams: 1 Ilzenayde de Araujo Neves.pdf: 1760905 bytes, checksum: 12209b0fdd08a4a6195c8dc7c1fb3d71 (MD5) / Made available in DSpace on 2017-02-15T11:31:33Z (GMT). No. of bitstreams: 1 Ilzenayde de Araujo Neves.pdf: 1760905 bytes, checksum: 12209b0fdd08a4a6195c8dc7c1fb3d71 (MD5) Previous issue date: 2011-07-29 / This study inquiry the chemical composition of essential oil of Croton jacobinensis, C. micans, C. rhamnifolius, C. muscicapa, C. pulegioides, C. rhamnifolius var. helliotropiifolius, Eugenia uvalha, C. sellowii species as well as evaluates the acaricide potential of C. jacobinensis, C. micans, C. rhamnifolius, C. muscicapa, E. uvalha and C. sellowii species. The major chemical constituents identified in essential oils obtained of diverse tissues from the Croton species were: (Z)-α-atlantone (24.3%, leaves, C. jacobinensis),Trans-isolongifolanone (22.8%, stem, C. jacobinensis ), α-bulnesene (32.9%, leaves, C. micans), guaiol (17.9%, stem, C. micans), α-Cedrene epoxide (23.3%, leaves, C. rhamnifolius), camphor (16.6%, stem, C. rhamnifolius), foeniculin (50.6%, leaves, and 72.7%, stem, C. muscicapa), 1.8-cineole (15.56%, leaves, C. pulegioides ), α-calacoreno (12.95%, stem, C. pulegioides), β-caryophyllene (20.82%, leaves, C. rhamnifolius var. helliotropiifolius) and guaiol (18.38%, stem, C. rhamnifolius var. helliotropiifolius). It were identified the compounds β-caryophyllene (24.3%) and (33.6%) of essential oils from leaves and flowers of E. uvalha, respectively, and caryophyllene oxide (42.4%) constituent of its stems. The major component identified on C. sellowii was β-caryophyllene (33.5%, 20.9% and 41.2%) in the leaves, stem and flowers, respectively. The essential oils showed acaricidal activity against Tetranychus urticae. The better response for fumigation activity was founding for the leaves of E. uvalha and stem of C. rhaminifolius (both LC50 of 0.20 μL / L air), followed by oil from stem of C. jacobinensis (LC50 = 0.30 μL / L air). For the best patch test result was reported from the oil of the stem of C. sellowii (LC50 = 0.53 mL / mL). While for the test repellent essential oil from leaves of C. sellowii showed a better result with a RC50 of 0.009 μL/cm2. For the dual-choice test, both oils tested showed a preference for the mites to go untreated until 24 hours drive of exposure and a preference to oviposit in untreated hard even after 48 hours of experiment. With these results all oils evaluated had the potential to be used in the integrated management of the mite. / O presente trabalho investiga a composição química do óleo essencial das espécies: Croton jacobinensis, C. micans, C. rhamnifolius, C. muscicapa, C. pulegioides, C. rhamnifolius var. helliotropiifolius, Eugenia uvalha, C. sellowii e avalia o potencial acaricida das espécies: C. jacobinensis, C. micans, C. rhamnifolius, C. muscicapa, E. uvalha e C. sellowii. Os constituintes químicos majoritários identificados nos óleos das diversas partes das espécies foram: (Z)-α-atlantona (24,3%, folhas C. jacobinensis), e Trans-isolongifolanona (22,8%, caule, C. jacobinensis), α-bulneseno (32,9%, folhas, C. micans), guaiol (17,9%, caule, C. micans), α-epóxido cedreno (23,3%, folhas, C. rhamnifolius), Cânfora (16,6%, caule, C. rhamnifolius), Foeniculina (50,6%, folhas, e 72,7%, caule, C. muscicapa), 1,8-cineol (15,56%, folhas, C. pulegioides), α-calacoreno (12,95%, caule, C. pulegioides), β-cariofileno (20,82%, folhas, C. rhamnifolius var. helliotropiifolius) e guaiol (18,38%, caule, C. rhamnifolius var. helliotropiifolius). No óleo essencial da espécie E. uvalha os compostos identificados em maior percentual foram o β-cariofileno (24,3% nas folhas e 33,6% nas flores) e óxido de cariofileno (42,4%) no caule. Na espécie C. sellowii o constituinte majoritário identificado foi o β-cariofileno (33,5%; 20,9% e 41,2%) nas folhas, caule e flores, respectivamente. Ambos os óleo testados apresentaram atividade acaricida contra Tetranychus urticae, o melhor resultado para atividade de fumigação foi descrita para as folhas de E. uvalha e caule de C. rhaminifolius (ambos com CL50 de 0,20μL/L de ar), seguido do óleo do caule de C. jacobinensis (CL50=0,30μL/L de ar). Para o teste de contato o melhor resultado foi relatado para o óleo do caule do C. sellowii (CL50=0,53μL/mL). Enquanto que para o teste de repelência o óleo das folhas de C. sellowii demonstrou um melhor resultado com uma CR50 de 0,009μL/cm2. Para o teste de dupla-escolha, ambos os óleos testados demonstraram uma preferência dos ácaros em ir para o disco não tratado até 24h de exposição e uma preferência de ovipositar no disco não tratado mesmo após 48h de experimento. Com esses resultados todos os óleos avaliados apresentaram potencial para ser usado no manejo integrado do ácaro.

Orientador: Carlos Gilberto Raetano / Banca: Mario Henrique F. do A. Dal Pogetto / Banca: Marcelo da Costa Ferreira / Banca: Wellington Pereira A.de Carvalho / Banca: Marco Antonio Gandolfo / Resumo: A otimização da deposição da pulverização pode ser obtida com a transferência de carga elétrica às gotas, as quais são fortemente atraídas pelas plantas, minimizando a exposição dos aplicadores e as perdas para o ambiente. Entretanto, a transferência de carga elétrica às gotas não é suficiente para melhorar a penetração da pulverização no dossel da cultura e, dessa forma, a assistência de ar associada à eletrificação das gotas pode contribuir para maior penetração da pulverização nas partes mais baixas da planta. O crisântemo de corte, Dendranthema grandiflora Tzvelev, especialmente a cultivar Reagan, apresenta problemas fitossanitários, como o ácaro-rajado, Tetranychus urticae, cujos danos podem comprometer a qualidade e a comercialização do produto final. O presente trabalho teve por objetivo avaliar o efeito da eletrificação das gotas associada à assistência de ar sobre os depósitos da pulverização em relação à técnica de pulverização convencional, bem como a eficiência dessas tecnologias no controle de Tetranychus urticae na cultura do crisântemo de corte. Nos ensaios os tratamentos foram constituídos pelas tecnologias de aplicação: 1. Convencional com ponta de duplo jato plano tipo TwinJet, TJ 8003; 2. Convencional, com ponta de jato cônico vazio TXVK-3; 3. Pulverizador semi-estacionário motorizado de jato lançado marca ESS, modelo MBP provido de carga elétrica e assistência de ar e; 4. O mesmo equipamento somente com a assistência de ar (sem eletrostática). Para comparar as tecnologias de pulverização quanto à eficiência no controle do ácaro-rajado, foi utilizado uma testemunha, sem aplicação do acaricida. O uso da assistência de ar associada ou não à eletrostática se mostrou... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The optimization of spraying deposition can be gotten with transferring electric charge to droplets, which are strongly attracted by the plants, decreasing operator exposure and losses to environment. However, this procedure by itself (the transference of electric charge to droplets) is not enough for the desirable spraying penetration in the crop canopy, thus the air assistance can be added to the electrostatic spraying to achieve better results. The cut chrysanthemum, Dendranthema grandiflora Tzvelev, specially the Reagan variety, shows phytosanitary problems as the two spotted spider mite Tetranychus urticae. It damages can commits the final product quality and trade. The goal of this work was evaluate the electrostatic and air assistance spraying on the spray deposition and on controlling Tetranychus urticae in cut chrysanthemum. Trials were carried out with the following treatments: 1. Conventional with TwinJet TJ 8003 double flat fan nozzle; 2. Conventional with TXVK-3 tip hollow cone; 3. Semi-stationary motorized jet launched spray, ESS brand, MBP model, with electric charge and air assistance; 4. The same equipment only with air assistance (without electric charge). To compare these spraying technologies regarding their efficiency in controlling the spider mite, a witness treatment was used without application of acaricide. The use of air assistance combined or not to the electrostatic spraying has shown efficient since larger amounts of deposits were found on the treatments 3 and 4. Additionally, it was permitted... (Complete abstract click electronic access below) / Doutor

Spine title: Interactions between plants and mites / Includes journal article by the author / Bibliography: leaves [1]-[9] / viii, 98, [110] leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1988

The objective of my work was to evaluate the efficiency of a native species of predatory mite Typhlodromus pyri Scheuten against two-spotted spider mite (Tetranychus urticae Koch) within IPM and organic hop growing and to find out if hop protection against T. urticae with the help of T. pyri can replace conventional hop protection based on miticides and if it can be profitable. The trials were carried out since 2011 till 2015 in three hop gardens at a research farm Stekník, which belongs to Hop Research Institute in Žatec (Saaz). The first experimental hop garden, where IPM is practiced, is called Černice I. The other one BIO is, as the name says, under organic regime. The third one called Kaplička (Little Chapel) I., served as a reference one because hop is grown there under a common conventional system with the use of miticides to control T. urticae. In regular intervals since the time when the first spider mites were observed at hop leaves till the harvest fifty leaves were sampled (17 from lower, 17 from middle and 16 from upper parts of hop plants) in the hop garden with IPM regime and in the organic hop garden. Population densities of eggs, mobile stages of T. urticae and T. pyri were assessed together with nymphs of predatory Thrips of the genus Aeolothrips, which occurred there naturally as the dominant native acarophagous predators. The results were statistically evaluated with the help of correlation analyses and t-test for independent groups. Efficiency of T. pyri and economical comparison with chemical protection were made as well. It is possible to conclude that after release of predatory mites and under using of selective pesticides the biodiversity is higher. Hop protection against two-spotted spider mite with the help of T. pyri can be profitable and it can replace chemical protection against this dangerous pest for many years. T. pyri is commonly more efficient if population density of T. urticae is lower. The tightest dependence at the level of 90% was statistically confirmed between occurrence of T. urticae eggs and its mobile stages. Statistically important difference was found out between the two different types of hop growing in the most of the cases.

Submitted by Nathália Faria da Silva (nathaliafsilva.ufv@gmail.com) on 2017-10-02T13:10:51Z No. of bitstreams: 1 texto completo.pdf: 635809 bytes, checksum: e37d831054d0f79444a7bba9655025d9 (MD5) / Made available in DSpace on 2017-10-02T13:10:51Z (GMT). No. of bitstreams: 1 texto completo.pdf: 635809 bytes, checksum: e37d831054d0f79444a7bba9655025d9 (MD5) Previous issue date: 2017-08-08 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Os ácaros predadores são comumente usados como agentes de controle biológico e as espécies Phytoseiulus macropilis e Neoseiulus californicus têm sido consideradas para serem liberadas em conjunto para controlar uma importante praga, o ácaro rajado Tetranychus urticae. Porque predadores que interagem podem interferir uns com os outros, um passo importante para a liberação bem-sucedida de múltiplos predadores em programas de controle biológico requer determinar como os predadores respondem à presença uns dos outros e se eles estão envolvidos em interações intraguilda. Diante disso, inicialmente, foi investigado se esses dois ácaros predadores evitam a presença um do outro. Sabe-se que predadores e parasitoides podem usar voláteis associados à presença de espécies competidoras quando forrageiam por áreas com presas ou hospedeiros. Portanto, foi analisado se as duas espécies de predadores usam substâncias voláteis que emanam de plantas com presas e heteroespecíficos para evitar locais de presa com a outra espécie de predador. Além disso, foi avaliado se esses predadores interagem através da predação intraguilda, em que predadores competidores matam e comem-se uns aos outros. No entanto, como não há consenso em relação aos critérios para avaliar a ocorrência de tal interação, primeiro foi explorado os critérios existentes e então foi sugerido diretrizes para o desenho de experimentos. Com base nessas diretrizes, foi investigado tanto a capacidade de P. macropilis e N. californicus para matar os estágios da outra espécie como a capacidade de se beneficiar alimentando-se destes estágios, ambos pré-requisitos para a ocorrência de predação intraguilda. As descobertas mais importantes sobre as possíveis interações entre esses predadores são que nenhum dos predadores usou voláteis para evitar locais de presas ocupadas pelos heterospecíficos. No entanto, eles se envolveram em predação intraguilda recíproca. Além disso, foi mostrado que a ontogenia claramente desempenhou um papel crítico na determinação da ocorrência de predação intraguilda dentro deste sistema de predadores. Foi discutido as possíveis explicações para não se evitar os odores produzidos e a interação entre estágios ontogênicos e interações intraguilda. / Predatory mites are commonly used as biological control agents and the species Phytoseiulus macropilis and Neoseiulus californicus have been considered to be released together to control an important pest, the two-spotted spider mite Tetranychus urticae. Because interacting predators may interfere with each other, an important step towards the implementation of successful release of multiple predators in biological control programs requires to resolve how predators respond to the presence of each other and whether they are involved in intraguild interactions. Given this, initially, I investigated whether these two predatory mites avoid the presence of each other. It is known that predators and parasitoids can use volatiles associated with the presence of competing species when foraging for patches with prey or hosts. I therefore investigated whether the two predator species use volatiles emanating from plants with prey and heterospecifics to avoid prey patches with the other predator species. Furthermore, I assessed whether these predators interact trough intraguild predation, in which competing predators also kill and eat each other. However, because there is no consensus regarding criteria to evaluate the occurrence of such interaction, I first explored existing criteria and suggested guidelines for the design of experiments. Based on these guidelines, I subsequently evaluated both the capacity of P. macropilis and N. californicus to kill stages of the other species and the capacity to benefit from feeding on these stages, both prerequisites for the occurrence of intraguild predation. The most important findings regarding the possible interactions among these predators are that neither of the predators used volatiles to avoid prey patches occupied by the heterospecific predators. However, they did engage in reciprocal intraguild predation. Moreover, I show that ontogeny clearly played a critical role in determining the occurrence of intraguild predation within this predator system. I discuss the possible explanations for the lack of odour-mediated avoidance and the interplay between ontogenetic stages and intraguild interactions.

Made available in DSpace on 2014-06-11T19:35:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-07-02Bitstream added on 2014-06-13T20:25:42Z : No. of bitstreams: 1 cerqueira_dtr_dr_botfca.pdf: 472475 bytes, checksum: 666774bdf6039b70f280c297ceac23be (MD5) / A otimização da deposição da pulverização pode ser obtida com a transferência de carga elétrica às gotas, as quais são fortemente atraídas pelas plantas, minimizando a exposição dos aplicadores e as perdas para o ambiente. Entretanto, a transferência de carga elétrica às gotas não é suficiente para melhorar a penetração da pulverização no dossel da cultura e, dessa forma, a assistência de ar associada à eletrificação das gotas pode contribuir para maior penetração da pulverização nas partes mais baixas da planta. O crisântemo de corte, Dendranthema grandiflora Tzvelev, especialmente a cultivar Reagan, apresenta problemas fitossanitários, como o ácaro-rajado, Tetranychus urticae, cujos danos podem comprometer a qualidade e a comercialização do produto final. O presente trabalho teve por objetivo avaliar o efeito da eletrificação das gotas associada à assistência de ar sobre os depósitos da pulverização em relação à técnica de pulverização convencional, bem como a eficiência dessas tecnologias no controle de Tetranychus urticae na cultura do crisântemo de corte. Nos ensaios os tratamentos foram constituídos pelas tecnologias de aplicação: 1. Convencional com ponta de duplo jato plano tipo TwinJet, TJ 8003; 2. Convencional, com ponta de jato cônico vazio TXVK-3; 3. Pulverizador semi-estacionário motorizado de jato lançado marca ESS, modelo MBP provido de carga elétrica e assistência de ar e; 4. O mesmo equipamento somente com a assistência de ar (sem eletrostática). Para comparar as tecnologias de pulverização quanto à eficiência no controle do ácaro-rajado, foi utilizado uma testemunha, sem aplicação do acaricida. O uso da assistência de ar associada ou não à eletrostática se mostrou... / The optimization of spraying deposition can be gotten with transferring electric charge to droplets, which are strongly attracted by the plants, decreasing operator exposure and losses to environment. However, this procedure by itself (the transference of electric charge to droplets) is not enough for the desirable spraying penetration in the crop canopy, thus the air assistance can be added to the electrostatic spraying to achieve better results. The cut chrysanthemum, Dendranthema grandiflora Tzvelev, specially the Reagan variety, shows phytosanitary problems as the two spotted spider mite Tetranychus urticae. It damages can commits the final product quality and trade. The goal of this work was evaluate the electrostatic and air assistance spraying on the spray deposition and on controlling Tetranychus urticae in cut chrysanthemum. Trials were carried out with the following treatments: 1. Conventional with TwinJet TJ 8003 double flat fan nozzle; 2. Conventional with TXVK-3 tip hollow cone; 3. Semi-stationary motorized jet launched spray, ESS brand, MBP model, with electric charge and air assistance; 4. The same equipment only with air assistance (without electric charge). To compare these spraying technologies regarding their efficiency in controlling the spider mite, a witness treatment was used without application of acaricide. The use of air assistance combined or not to the electrostatic spraying has shown efficient since larger amounts of deposits were found on the treatments 3 and 4. Additionally, it was permitted... (Complete abstract click electronic access below)

Historically, most twospotted spider mite, Tetranychus urticae Koch, infestations occurred during the late season near maturity, but since 2005, infestations of cotton have become more common throughout the entire season. Several factors may have contributed to the increasing frequency of mites in seedling cotton, one of which is a shift in production practices from furrow applied aldicarb to neonicotinoid seed treatments for thrips control. Another factor that may impact T. urticae densities in seedling cotton is a shift from pre-plant tillage to conservation tillage or no-till cropping systems. Although the literature confirms that T. urticae can cause extensive cotton yield losses, there is a need to further refine potential late-season yield loss. From 2007 to 2009 a series of experiments were conducted to address these issues. In a series of 12 field experiments, neonicotinoid seed treatments resulted in twospotted spider mite densities greater than those in the untreated check, aldicarb, and acephate treatments. Untreated check and aldicarb treatments had the lowest mite densities. Only aldicarb controlled mites compared to the untreated check. A twospotted spider mite host survey determined that henbit, Lamium amplexicaule L., was the most consistent and preferred host. Carolina geranium, Geranium carolinianum L., cutleaf geranium, Geranium dissectum L., vetch, Vicia spp., volunteer soybean, Glycine max L., purple deadnettle, Lamium purpureum L., and spiny sowthistle, Sonchus asper (L.) Hill, were other frequently infested dicotyledonous species. Herbicide burndown timing in reduced tillage cotton production was not critical, given all weeds were killed before cotton was planted. The herbicide glufosinate was efficacious against T. urticae, providing control equal to low- to mid-rates of labeled acaricides. Including glufosinate in a herbicide burndown program was only beneficial for mite control if living weeds were present at planting. Artificial infestation experiments were adversely affected by unseasonably wet and cool weather. Infestations established at the third true leaf resulted in an average yield loss of 44.7%. It is difficult to make any conclusions about infestations made from first bloom and later because of the difficulty in establishing mite populations later in the season.

The twospotted spider mite, Tetranychus urticae Koch, is a serious pest of many ornamental plants (Johnson and Lyon, 1991). Pesticide resistance, the high cost of pesticides and loss of production time have raised interest by growers to introduce predatory phytoseiid mites to manage twospotted spider mites and reduce their need for acaricide applications (Sabelis, 1981). The predatory mite Phytoseiulus persimilis Athias-Henriot has been used successfully in integrated pest management programs for T. urticae suppression. Despite the success of P. persimilis in reducing populations of T. urticae, acaricide applications may still necessary due to limitations associated with the effectiveness of P. persimilis introductions. The objectives of this study were to; 1. Measure the effects of acaricides on the density and age structure of T. urticae populations. 2. Determine the compatibility of acaricides in an IPM program by measuring the toxicity of residues to P. persimilis and T. urticae adults. 3. Study the feeding behavior of P. persimilis on T. urticae. 4. Measure the effects of combinations of acaricides followed by release of P. persimilis on T. urticae populations using greenhouse trials. The effects of ten acaricides on T. urticae populations were measured on infested Buddleia x davidii 'White Profusion' cuttings. Acaricides did not alter age structure in predictable manner. Initial analysis of results demonstrates that cuttings treated with acaricides had age structures that were different from control treatments. However, these differences were not distinguishable from natural fluctuations in the age structure. Chlorfenapyr may have changed the age structure of T. urticae. Azadirachtin, pyridaben and spinosad did not suppress T. urticae populations at the rates and formulations tested in this trial. Abamectin, bifenthrin, chlorfenapyr, Gowan 1725,oil and neem oil suppressed T. urticae populations. Hexythiazox suppressed T. urticae populations but these results were not seen until two weeks after application. The effects of acaricide residues were tested on adult P. persimilis and T. urticae 1, 3, 7, and 14 days after application using a leaf disk system. Abamectin, Gowan 1725, hexythiazox, horticultural oil, neem oil, pyridaben and spionsad were not toxic to P. persimilis adults while bifenthrin and chlorfenapyr residues were toxic to P. persimilis. Tetranychus urticae mortality from chlorfenapyr residues was significantly greater than the control 1,3,7 and 14 days after application. Tetranychus urticae mortality from bifenthrin and abamectin residues was significantly greater than the control 3, 7, and 14 days after application. Tetranychus urticae mortality caused by Gowan 1725, horticultural oil, and neem oil residues was significantly greater than the control 1 day after application, while mortality from hexythiazox and spinosad residues was not significantly greater than the control at any of the times tested in this study. Phytoseiulus persimilis feeding behavior studies examining life stage preference tests and functional response studies were conducted on bean leaf disks. We found P. persimilis functional response to be a type II response for both eggs and adults with handling times of 0.079 hours for eggs and 3.399 hours for adults. The effects of a combination of acaricides followed by release of P. persimilis on T. urticae populations was tested using greenhouse studies conducted on infested Buddleia plants. In the first trial, severe plant damage occurred despite a reduction in the mean number of mites per leaf in treatments with oil+ predator treatments 7 days after release. Results from the second greenhouse trial produced plants with less visual damage compared to those in the first greenhouse trial. Treatments with predators alone and predators + acaricides produced similar results. However, treatments with predators had a mean numbers of mites per leaf that were significantly less than treatments with acaricides alone. The results demonstrate that the acaricides tested in the second greenhouse trial allowed the predators to provide suppression of T. urticae populations. A high release rate was used in the second greenhouse trial and lower release rates as well as different acaricide predator combinations need be tested to explore the possibility of new management techniques. Our results suggest that the number of pest mites present in the crop may be the most important factor affecting the success of biological control with predators. Combinations of oil applications followed by introduction of P. persimlis 3 days after release provided suppression of T. urticae populations in a meaningful time frame. I was not able to shape the age structure of T. urticae populations in a predictable manner with acaricide applications. Phytoseiulus persimilis does not have a prey-stage preference when feeding on T.urticae, but the shorter handling time for eggs may indicate that they are better able to suppress populations with higher proportions of eggs. However, we cannot determine if P. persimilis can keep T. urticae populations composed of predominately of eggs below threshold levels because our greenhouse trials did not test this hypothesis. Phytoseiulus persimilis feeding on adult T. urticae may suppress T. urticae populations below threshold levels because a reduction in the number of adults will lead to a reduction in the number of T. urticae eggs deposited on a plant. Our research suggests that abamectin and oil are two acaricides that would be less detrimental to the survival of P. persimilis. Additional greenhouse trials with compatible acaricides should be conducted as well as research on the threshold density of T. urticae that will allow P. persimilis to provide adequate control. / Master of Science

O cultivo de flores iniciou-se no Brasil como atividade econômica em maior escala a partir de 1960. Atualmente, cerca de 5.000 produtores dedicam-se à floricultura em todo país. O setor gera um faturamento estimado em U$ 400 milhões/ano. No varejo, o faturamento é estimado em U$ 1,3 bilhões/ano. Acredita-se que a floricultura brasileira gera atualmente entre 120 a 160 mil empregos, caso seja considerada toda a cadeia produtiva que envolve o campo, a distribuição, o comércio varejista e os segmentos de apoio. O ácaro rajado, Tetranychus urticae Koch, é uma das principais pragas em plantas ornamentais, com destaque para o cultivo de gérberas e roseiras. O uso excessivo de acaricidas para o controle desta praga tem trazido sérios problemas ao ambiente e à saúde humana. Diversos trabalhos têm mostrado o potencial dos ácaros predadores da família Phytoseiidae para o controle de T. urticae. Alguns parecem ser promissores no controle daquela praga, sendo Neoseiulus californicus (McGregor) um deles. No Brasil, não há nenhuma informação sobre o potencial deste predador em cultivos comerciais de gérberas e roseiras. O objetivo do presente trabalho foi: estabelecer estratégias de manejo de T. urticae em cultivos de gérberas e roseiras; estabelecer um sistema de criação massal de N. californicus; determinar o ciclo de vida de duas espécies de ácaros predadores que pudessem ser eventualmente utilizadas em futuros estudos ou estratégias de manejo de pragas daquelas culturas. Uma metodologia para estimar a densidade populacional de T. urticae sobre Canavalia ensiformis (L.) DC foi determinada (para sistemas de criação massal de ácaros predadores) através da contagem de T. urticae em 3 regiões de 1 cm2 cada (base, meio e ápice). A maior precisão na determinação do número total de ácaros na folha foi obtida através da estimativa dos ácaros na região basal e do somatório das 3 regiões [coeficiente de determinação (r2) = 0, 63 e 0,85, respectivamente]. O sistema de produção massal de N. californicus mostrou-se satisfatório. A partir de uma estrutura simples e com um custo relativamente baixo foi possível produzir até 300.000 ácaros predadores a cada 15 dias nos períodos mais quentes do ano. Em relação às tabelas de vida dos predadores estudados, Proprioseiopsis cannaensis (Muma) e Neoseiulus barkeri Hughes não completaram o desenvolvimento quando alimentados com Phyllocoptruta oleivora (Ashmead). Os valores de rm de P. cannaensis foram -0,05, -0,09 e 0,002 alimentado com Brevipalpus phoenicis (Geijskes), T. urticae e pólen de Typha angustifolia L, respectivamente. Os valores de rm de N. barkeri foram -0,03, 0,139 e 0,141, alimentado com B. phoenicis, T. urticae e pólen, respectivamente. N. barkeri parece ter potencial no controle de ácaros Tetranychidae, embora situações de campo devam ser testadas. Em relação às liberações de N. californicus em cultivos de gérberas e roseiras, os resultados foram altamente satisfatórios. Além de menor impacto ambiental, a utilização deste predador associada às aplicações de acaricidas seletivos mostrou-se uma alternativa eficiente e economicamente viável no controle de T. urticae. / Flower growing on a large scale as an economic activity in Brazil started in 1960. Currently, approximately 5.000 farmers practice floriculture in the whole country. The sector generates an estimated income of U$ 400,000/year. Retail income is estimated at US$ 1.3 billions/year. It is currently believed that Brazilian flower industry generates between 120 and 160 thousand employment opportunities if all the productive chains are considered which involve field work, distribution, retail sales and support segments. The two spotted spider mite, Tetranychus urticae Koch, is one of the principal pests of ornamental plants and prominently attacking gerberas and roses. The excessive use of acaricides for the control of this pest poses serious problems on the environment and human health. Several studies have demonstrated the potential of predatory mites from the family Phytoseiidae in the control of T. urticae. Some of these predators seem to be promising for the control of this pest among them Neoseiulus californicus (McGregor). In Brazil, information about the potential of this predator in commercial crops of gerberas and roses is lacking. The objective of the current work was: establish management strategies of T. urticae in gerbera and rose flowers; establish a mass rearing system for N. californicus; determine the life cycle of the two predatory mite species that could be used in future studies or management strategies for pests on these crops. A method for estimating population density of T. urticae on Canavalia ensiformis (L.) DC was determined (for mass rearing system of predatory mites) through counting of T. urticae in 3 regions of 1 cm2 each (bottom, middle and apex). The highest precision in the determination of the total number of mites on leaves was obtained through mite estimates at the basal region and the summations of the 3 regions [coefficient of determination (r2) = 0. 63 and 0.85, respectively]. The mass production system of N. californicus was shown to be satisfactory. Starting with a simple structure and with a relatively low cost, it was possible to produce up to 300.000 predatory mites every 15 days during the hottest period of the year. In relation to the life tables of the studied predators, Proprioseiopsis cannaensis (Muma) and Neoseiulus barkeri Hughes did not complete their development when fed on Phyllocoptruta oleivora (Ashmead). The rm values of P. cannaensis were -0.05, -0.09 and 0.002 when fed on Brevipalpus phoenicis (Geijskes), T. urticae and pollen of Typha angustifolia L, respectively. The rm values of N. barkeri were -0.03, 0.139 and 0.141, when fed on B. phoenicis, T. urticae and pollen, respectively. N. barkeri seem to have potential for the control of tetranychid mites, however, field conditions should be tested. In relation to release of N. californicus in gerbera and rose flowers, the results were highly satisfactory. In addition to lower environmental impact, the use of this predator in combination with selective acaricides shows an efficient and economically viable alternative for the control of T. urticae.