Four to six separate inundative releases of ~30,000 to 50,000 T. ostriniae per 0.02 ha significantly reduced damage by O. nubilalis in bell pepper. Egg parasitization averaged 48.7% in T. ostriniae release plots, which was significantly higher than non-release plots (1.9%). Also, cumulative green pepper fruit damage averaged 8.7% in release plots, which was significantly less than non-release plots (27.3%). Pesticides tested against T. ostriniae were spinosad and methoxyfenozide. Spinosad adversely affected adult T. ostriniae producing 100% mortality at the field rate of 498 mg [AI]/L for both the preimaginal and adult toxicity tests. Use of T. ostriniae can provide effective control of O. nubilalis in pepper compared to conventional and organic spray regimes (Spinosad and methoxyfenozide respectively). Augmentative releases of T. ostriniae integrated with methoxyfenozide with its limited toxicity to both preimaginal and adult stages indicate that it is a superior candidate for control O. nubilalis. To determine the behavioral differences of T. ostriniae and its response to O. nubilalis in green bell peppers, experiments were carried out to classify likely areas of O. nubilalis oviposition within the green pepper plant canopy. A total of 426 O. nubilalis egg masses were found on pepper plants during our study. Over 92% of egg masses were found on the lower surface of the leaf compared with the upper surface indicating a significant ovipositional preference for the undersides of leaves in 2002 ( x2 = 9.68; df = 1; P < 0.05) followed by similar results in 2004 (x2 = 4.34; df = 1; P < 0.05). No significant differences were found in the observed spatial distribution of egg masses among the three vertical strata in either 2002 or 2004 (x2 = 1.75; df = 2; P < 0.05 and x2 = 5.69; df = 2; P < 0.05 respectively). Field release rates of 17.0 foraging T. ostriniae females can achieve 80.0% parasitism of O. nubilalis egg masses distributed throughout the pepper plant canopy found primarily on the undersides of leaves. These data demonstrate that T. ostriniae has potential as a biocontrol agent for O. nubilalis in solanaceous crops. / Ph. D.

L’établissement correspond à la formation d’une population pérenne dans l’aire d’introduction. Les populations introduites ayant des effectifs faibles, elles sont sujettes à plusieurs mécanismes augmentant leurs risques d’extinction. La structure spatiale de l’aire d’introduction, une mosaïque hétérogène de patchs d’habitat appelée « paysage », peut affecter la persistance de la population introduite. L’objectif de cette thèse est d’étudier l’interaction entre cette structure spatiale et ces mécanismes, ainsi que leur impact sur l’établissement. Les recherches entreprises ont été conduites en utilisant des modèles stochastiques afin de simuler des invasions et faire émerger des prédictions, et en testant expérimentalement ces prédictions grâce à des introductions artificielles de Trichogramma chilonis en microcosmes. Ces travaux ont permis d’identifier un effet fort de la connectivité du site d’introduction, qui peut diminuer les chances d’établissement au niveau local en favorisant l’émigration depuis le site d’introduction, et augmenter les chances d’établissement à un niveau plus large en permettant la colonisation d’autres patchs dans l’aire d’introduction. Au niveau du paysage, nous avons identifié l’impact des hubs, des patchs concentrant les flux de dispersion, qui accroissent fortement la vitesse de colonisation mais diminuent le taux d’établissement. L’établissement était également favorisé par l’agrégation de la ressource et la colonisation par sa dissémination à travers le paysage. La nature stochastique des dynamiques de colonisation est telle qu’il est nécessaire de les prendre en compte pour étudier l’établissement. / Establishment is an important stage of biological invasions, which corresponds to the formation of a persistent population in the introduction area. It is not trivial, as introduced populations are often small, and subject to various specific mechanisms, which increase extinction risks. The spatial structure of the introduction area, which is usually a heterogeneous mosaic of habitat patches called a “landscape”, can interact with those mechanisms and impact the introduced population persistence. This thesis objective is to study the interaction between this spatial structure and those mechanisms, as well as their impact on establishment. On the one hand, we used stochastic models to simulate invasions and formulate predictions. On the other hand, we tested these predictions by performing artificial introductions of Trichogramma chilonis in laboratory microcosms. We were able to identify the impact of the introduction site connectivity, which could decrease establishment probabilities at a local level by increasing the emigration rate from the introduction site, and increase establishment at the landscape level by increasing the colonisation rate of other patches in the introduction area. At the landscape level, we identified the impact of hubs, i.e. patches concentrating dispersal fluxes. They strongly increased colonisation speed, but also decreased establishment. The clustering of resources increased establishment, while its scattering increased colonization. Our results show that introduced population dynamics are highly sensitive to their size. The stochastic nature of colonization dynamics is also necessary to study establishment.

Made available in DSpace on 2016-12-23T14:37:39Z (GMT). No. of bitstreams: 1 Carolina Oliveira Bernardes.pdf: 507333 bytes, checksum: f1bdcef3de907c50ccb23b8a69a35e0a (MD5) Previous issue date: 2009-12-10 / A soja é considerada um dos produtos de maior importância para a economia brasileira e dentre as pragas mais importantes, que limitam a sua produção, destaca-se Anticarsia gemmatalis. Visando reduzir a utilização de inseticidas no controle de pragas, têm-se buscado alternativas de controle, dentre as quais a utilização do controle biológico. Entre os agentes de controle biológico se destacam a bactéria entomopatogênica Bacillus thuringiensis (Bt) e os parasitoides de ovos do gênero Trichogramma. Este estudo avalia a interação desses dois agentes de controle biológico utilizados no controle de A. gemmatalis. Inicialmente, foram feitos testes de seleção com onze linhagens de Trichogramma, sendo a linhagem T. pretiosum 12, a que apresentou melhor desempenho para esta praga. Testes de patogenicidade e virulência foram realizados com 23 isolados de Bt, além do produto comercial Dipel® (B. thuringiensis var. kurstaki), para selecionar os mais agressivos para o inseto. Entretanto, os isolados 80, 997, 1054, 716 e 633 e o Dipel® foram os mais promissores. Por fim, foram realizados dois experimentos de interação entre o T. pretiosum 12, os isolados 80, 997, 1054, 716 e 633 e Dipel®. Foi observado que para o experimento em que os isolados foram misturados ao alimento houve uma interação positiva, em que os isolados 633 e 1054 causaram aumento no parasitismo. Com relação ao segundo experimento, foi observado que a imersão das cartelas com ovos de A. gemmatalis nas suspensões, contendo os diferentes isolados de Bt 80, 633, 716, 993, 1054 e o Dipel® reduziu o número total de ovos parasitados devido à repelência do T. pretiosum 12 aos ovos imersos em suspensão com Bt. Estudos histopatológicos da interação do Bt com as células do intestino médio de Trichogramma são necessários para elucidar como o Bt atua no inseto adulto. Esses estudos, aliados à caracterização molecular das toxinas presentes nos isolados, contribuirão para elucidar a interação parasitoide x entomopatógeno x hospedeiro / Soybean is considered one of the most important products to the brazilian economy and among the most important pests, which make its production limited, Anticarsia gemmatalis is detached. Aiming to reduce the use of insecticides on the pests control, alternatives of control have been searched, among these the use of biological control. Among the biological control agents the entomopathogenic bacterium Bacillus thuringiensis (Bt) and the egg parasitoids from the genus Trichogramma are detached. This study evaluates the interaction between these two biological control agents used on A. gemmatalis control. Initially selection tests were made with eleven Trichogramma strains and the strain T. pretiosum 12 was the one which presented best performance for this pest. Patogenicity and virulence tests were carried out with 23 Bt isolates and the commercial product Dipel® (B. thuringiensis var. kurstaki) to select the most virulent ones for the insect. This way the isolates 80, 997, 1054, 716, 633 and Dipel® were the most promising. With these results, two interaction experiments were performed among T. pretiosum 12, the isolates 80, 997, 1054, 716, 633 and Dipel®. It was observed that for the experiment in which the isolates were mixed to the food there was a positive interaction, where the isolates 633 and 1054 caused an increase on parasitism. Concerning the second experiment it was observed that the immersion of the cards containing A. gemmatalis eggs in the different Bt isolates 80, 633, 716, 993, 1054 and Dipel® reduced the total number of parasitized eggs due to repellence of T. pretiosum to the immersed eggs in Bt suspensions. Histopathologic studies of Bt interaction with T. pretiosum midgut cells are necessary to elucidate how Bt acts on the adult insect. These studies allied to molecular characterization of the toxins presented on the isolates will contribute to elucidate the interaction parasitoid x entomopathogen x host

Les parasitoïdes du genre Trichogramma sont des micro-hyménoptères oophages très utilisés comme auxiliaires de lutte biologique. Ma thèse a pour objet la caractérisation phénotypique des stratégies de mouvement de cet auxiliaire, spécifiquement les mouvements impliqués dans l’exploration de l’espace et la recherche des œufs hôtes. Ces derniers sont des phénotypes de grande importance dans le cycle de vie des trichogrammes, et aussi des caractères d’intérêt pour évaluer leur efficacité en lutte biologique. Les trichogrammes étant des organismes de très petite taille (moins de 0,5 mm), difficilement observables, l’étude de leur mouvement peut tirer profit des avancées technologiques dans l’acquisition et l’analyse automatique des images. C’est cette stratégie que j’ai suivi en combinant un volet de développement méthodologique et un volet expérimental. Dans une première partie méthodologique, je présente trois grands types de méthodes d’analyse d’images que j’ai utilisées et contribué à développer au cours de ma thèse. Dans un second temps, je présente trois applications de ces méthodes à l’étude du mouvement chez le trichogramme. Premièrement, nous avons caractérisé au laboratoire les préférences d’orientation (phototaxie, géotaxie et leur interaction) lors de la ponte chez 18 souches de trichogramme, appartenant à 6 espèces. Ce type d’étude requérant le dénombrement d’un très grand nombre d’œufs (sains et parasités), il a été développé un nouvel outil dédié, sous forme d’un plugin ImageJ/FIJI mis à disposition de la communauté. Ce plugin flexible automatise et rend plus productible les tâches de dénombrement et d’évaluation de taux de parasitisme, rendant possible des screenings de plus grande ampleur. Une grande variabilité a pu être mise en évidence au sein du genre, y compris entre souches d’une même espèce. Cela suggère qu’en fonction de la strate végétale à protéger (herbacée, arbustive, arborée), il serait possible de sélectionner des souches afin d’optimiser leur exploitation de la zone ciblée. Dans un second temps, nous avons caractérisé les stratégies d’exploration (vitesses, trajectoires, ...) d’un ensemble de souches et d’espèces de trichogramme pour rechercher des traits propres à chaque souche ou espèce. Pour cela, j’ai mis en œuvre une méthode de tracking de groupes de trichogrammes sur enregistrement vidéo sur de courtes échelles de temps à l’aide du logiciel Ctrax et de scripts R. L’objectif était de développer un protocole de caractérisation haut-débit du mouvement de souches de trichogrammes et d’étudier la variabilité de ces traits au sein du genre. Enfin, nous avons conduit une étude de la dynamique de propagation dans l’espace de groupes de trichogrammes chez l’espèce T. cacoeciae, en mettant au point un dispositif expérimental innovant permettant de couvrir des échelles de temps et d’espace supérieures à celles habituellement imposées par les contraintes de laboratoire.Grâce à l’utilisation de prises de vue très haute résolution / basse fréquence et d’un pipeline d’analyse dédié, la diffusion des individus peut être suivie dans un tunnel de plus 6 mètres de long pendant toute une journée. J’ai notamment pu identifier un effet de la densité en individus ainsi que de la distribution des ressources sur la dynamique de propagation (coefficient de diffusion) des trichogrammes testés. / Parasitoids of the genus Trichogramma are oophagous micro-hymenoptera widely used as biological control agents. My PhD is about the phenotypic characterization of this auxiliary's movement strategies, specifically the movements involved in the exploration of space and the search for host eggs. These phenotypes have great importance in the life cycle of trichogramma, and also of characters of interest to evaluate their effectiveness in biological control program. Trichogramma being very small organisms (less than 0.5 mm), difficult to observe, the study of their movement can take advantage of technological advances in the acquisition and automatic analysis of images. This is the strategy I followed by combining a methodological development component and an experimental component. In a first methodological part, I present three main types of image analysis methods that I used and helped to develop during my thesis. In a second time, I present three applications of these methods to the study of the movement of Trichogramma. First, we characterized in the laboratory the orientation preferences (phototaxis, geotaxis and their interaction) during egg laying in 22 trichogram strains belonging to 6 species. This type of study requires the counting of a large number of eggs (healthy and parasitized), it was developed a new dedicated tool in the form of an ImageJ / FIJI plugin made available to the community. This flexible plugin automates and makes more productive the tasks of counting and evaluation of parasitism rate, making possible screenings of greater magnitude. A great variability could be highlighted within the genus, including between strains of the same species. This suggests that depending on the plant layer to be protected (grass, shrub, tree), it would be possible to select trichogramma’s strains to optimize their exploitation of the targeted area. In a second time, we characterized the exploration strategies (velocities, trajectories, ...) of a set of 22 strains from 7 trichogramma species to look for traits specific to each strain or species. I implemented a method for tracking a trichogramma group on video recorded on short time scales using the Ctrax software and R scripts. The aim was to develop a protocol for high-throughput characterization of trichogramma strains movement and to study the variability of these traits within the genus. Finally, we conducted a study of the propagation dynamics in trichogramma group from the species T. cacoeciae, by developing an innovative experimental device to cover scales of time and space greater than those usually imposed by laboratory constraints. Through the use of pictures taken at very high resolution / low frequency and a dedicated analysis pipeline, the diffusion of individuals can be followed in a tunnel longer than 6 meters during a whole day. In particular, I was able to identify the effect of the population density as well as the distribution of resources on the propagation dynamics (diffusion coefficient) and the parasitism efficiency of the tested strain.

Made available in DSpace on 2014-06-11T19:27:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-10Bitstream added on 2014-06-13T19:56:01Z : No. of bitstreams: 1 almeida_amb_me_jabo.pdf: 563129 bytes, checksum: 02996595fd1963684492476407b56da9 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A traça-das-crucíferas Plutella xylostella é relatada como uma das principais pragas das crucíferas no Brasil e no mundo. Sua principal forma de controle ainda é o químico, mas seu uso indiscriminado tem causado problemas de resistência de algumas populações, além de matar seus inimigos naturais e trazer malefícios para o ambiente e para o homem. Alguns estudos de controle biológico vêm sendo realizados para o controle dessa praga, dentre eles destacando-se o uso de fungos entomopatogênicos e de parasitóides. Assim, foi realizado um estudo com o objetivo de determinar a concentração e tempo letal 50 e 90 dos fungos entomopatogênicos Beauveria bassiana, Isaria fumosorosea e Metarhizium anisopliae para lagartas de P. xylostella, e a patogenicidade de isolados deste fungos para ovos, lagartas, pupas e adultos da praga. Foram utilizados cinco isolados de cada espécie fúngica, sendo que os mais patogênicos à todas as fases do ciclo de vida do inseto foram utilizados para investigar a interação dos entomopatógenos com os parasitóides Trichogramma pretiosum e T. exiguum e com o predador Podisus nigrispinus. As CL90 para B. bassiana, I. fumosorosea e M. anisopliae foram 2 x 108, 8,65 x 107 e 1,77 x 108 conídios mL-1, respectivamente, sendo que estas foram utilizadas em todos os experimentos posteriores. Os isolados CB 75 e IBCB 133 de I. fumosorosea mostraram uma ação patogênica eficiente para ovos da praga, causando, respectivamente, 66 e 70% de mortalidade. Para a fase de lagarta os isolados E9 e o IBCB 425 de M. anisopliae, causaram, respectivamente, 98 e 96% de mortes. Considerando a mortalidade total de pupas tratadas e seus adultos emergidos, a ação dos isolados AM 09, JAB 07, IBCB 74 e IBCB 87 não diferiu significativamente (p<0,01) causando, respectivamente, 94, 92, 82 e 100% de mortalidade do inseto. Para os adultos não houve diferença significativa... / The diamondback moth Plutella xylostella is related as one of mainly pests in crucifers in Brazil. Its mainly control way still is chemical, but its indiscriminate use has been causing resistance in some populations, besides to kill its natural enemies and bring bad things for environment and human. Some studies of biological control have been made, outsdanding entomopathogenic fungi and parasitoids. Thus, it was determinated the lethal time and concentration 50 and 90 of entomopathogenic fungi Beauveria bassiana, Isaria fumosorosea and Metarhizium anisopliae to larvae of P. xylostella, and the pathogenicity of strains of these fungi to eggs, larvae, pupae and adults of the pest. It was used five strains of each fungal specie, and the most pathogenic were used to investigate the interaction between entomopathogens and the parasitoids Trichogramma pretiosum and T. exiguum and with the predator Podisus nigrispinus. The LC90 for B. bassiana, I. fumosorosea and M. anisopliae were 2 x 108, 8,65 x 107 e 1,77 x 108 conidia ml-1, respectively, being used in the following bioassays. The strains CB 75 and IBCB 133 of I. fumosorosea showed an efficient pathogenic action for the eggs of the pest, causing, respectively, 66 and 70% of mortality. For larvae the isolates E9 and IBCB 425 of M. anisopliae, caused, respectively, 98 and 96% of death. Considering the total mortality of treated pupae and its emerged adults, the action of AM 09, JAB 07, IBCB 74 and IBCB 87, did not differ significantly (p<0,01) causing, respectively, 94, 92, 82 e 100% of insect mortality. For adults there was no statistical difference between the B. bassiana strains. The isolates CB 75 and IBCB 133 of I. fumosorosea caused, respectively, 98 and 94% of adults death of P. xylostella and the strains E9, IBCB 159 and IBCB 425 of M. anisopliae, caused 100, 92 and 96% of death. For the obtained results in all the stages of this study... (Complete abstract click electronic access below)

Made available in DSpace on 2016-12-08T16:44:36Z (GMT). No. of bitstreams: 1 PGPV08MA061.pdf: 1448249 bytes, checksum: 698177cc88a738bc51ae342ee9a11bb0 (MD5) Previous issue date: 2008-12-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Four trails were conducted with the objective to study the potential of neem oil, Azadirachta indica, and biotherapics on the control of lepidoptera pests in organic soybean culture. Leaf consumption, development and mortality of Anticarsia gemmatalis Hubner, 1818 (Lepidoptera: Noctuidae) were evaluated in laboratory, with larvae submitted to the treatments: leaf sprayed with neem oil (0.5%), leaf sprayed with neem oil (1.5%), leaf sprayed with neem oil (2.5%), leaf and larvar sprayed with neem oil (1.5%), leaf sprayed with A. gemmatalis macerated bioteraphic 10 mL.L-1, leaf sprayed with A. gemmatalis triturated bioteraphic 10 mL.L-1, leaf and larvae sprayed with A. gemmatalis triturated bioteraphic 10 mL.L-1, leaf sprayed with Dipel® 0,5 L.ha-1 and control. To the experiment with the soybean shoot borer Epinotia aporema Wals (Lepidoptera: Noctuidae) in the field, the treatments: neem oil (1; 3 and 5%), E. aporema triturated biotherapic, Dipel® SC (Bacillus thuringiensis) 0.5 and 0.7 L ha-1 and control with no intervention, were applied twice in a completely randomized blocks design with four replicates. Additionally, a study to verify the residual effect of the products was performed by offering soybean leaves sprayed in the field to A. gemmatalis at the laboratory, at 0, 4 and 8 days after spraying. To evaluate the compatibility of these products with the biological control, a selectivity test to natural enemies was conducted under in vitro conditions, according to the International Organization of Biological Control (IOBC), using the immature phase of the parasitoid Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae). Neem oil reduced leaf consumption, caused insects deformation and high mortality indexes. The biotherapics did not have effect to leaf consumption and neither caused deleterious effects in A. gemmatalis development. The two highest concentrations of neem oil showed control efficiency of E. aporema superior to 80%, followed by the treatment Dipel® SC 0,7 L ha-1, but did not reach a control index higher than 50%. Epinotia aporema biotherapics (30 CH) did not show effect on the own species. Adverse effects of neem oil and B. thuringiensis in larvae of A. gemmatalis were more evident when the time between spraying and starting larvae feeding was smaller. The residual effect of neem oil was higher according to the increase of the concentration used. Biotherapics had little influence in the development and mortality of A. gemmatalis. In the selectivity test, A. gemmatalis biotherapics and Dipel® SC were classified as innocuous, neem oil (0.5%) as slightly harmful, and neem oil 1.5% and 2.5% as moderately harmful / O objetivo foi estudar o potencial do óleo de nim (Azadirachta indica) e de preparados homeopáticos no controle de lepidopteros praga na cultura da soja conduzida sob o sistema orgânico. O consumo foliar, o desenvolvimento e a mortalidade de Anticarsia gemmatalis Hubner, 1818 (Lepidoptera: Noctuidae) foi avaliado em laboratorio, a partir de lagartas submetidas aos seguintes tratamentos: folha pulverizada com óleo de nim a 0,5, 1,5 e 2,5%, folha pulverizada + lagarta pulverizada com óleo de nim 1,5%, folha pulverizada com nosódio macerado de A. gemmatalis 10 mL.L-1, folha pulverizada com nosódio triturado de A. gemmatalis 10 mL.L-1, folha pulverizada + lagarta pulverizada com nosódio macerado de A. gemmatalis 10 mL.L-1, folha pulverizada + lagarta pulverizada com nosódio triturado de A. gemmatalis 10 mL.L-1, folha pulverizada com Dipel® SC (Bacillus thuringiensis) 0,5 L.ha-1 e testemunha sem intervenção. Para o experimento com broca-das-axilas, Epinotia aporema Wals (Lepidoptera: Tortricidae) a campo, foram utilizados os seguintes tratamentos: óleo de nim a 1, 3 e 5%, nosodio triturado de E. aporema, Dipel® SC 0,5 e 0,7 L ha-1 e testemunha sem intervenção, com delineamento de blocos ao acaso e quatro repetições, sendo realizado duas aplicações, a primeira no estádio V4 a V5 e a segunda 15 dias após a primeira. Adicionalmente, foi realizado um ensaio para verificar o poder residual desses produtos, através do fornecimento de folhas pulverizadas a campo para A. gemmatalis em laboratório em três épocas diferentes, aos 0, 4 e 8 dias após a pulverização. Para verificar a compatibilidade desses produtos com o controle biológico, foi realizado teste de seletividade a inimigos naturais em laboratório, segundo as normas padronizadas da International Organization of Biological Control (IOBC), utilizando o parasitóide de ovos Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) na fase imatura (pupa). O óleo de nim reduziu o consumo foliar, provocou deformações nos insetos e causou índice de mortalidade superior a 98% nas duas maiores concentrações. Os preparados homeopáticos não promoveram redução no consumo foliar, assim como não provocaram efeitos deleterios no desenvolvimento das lagartas de A. gemmatalis. O óleo de nim nas duas maiores concentrações apresentou eficiência de controle de E. aporema superior a 80%, seguido do tratamento Dipel® SC 0,7 L ha-1, porém, o tratamento com Dipel® SC 0,7 L ha-1 não alcançou índice de controle superior a 50%. Nosódio de E. aporema na 30CH não apresentou efeito sobre a própria espécie. Os efeitos adversos do óleo de nim e do B. thuringiensis provocados em lagartas de A. gemmatalis foram mais evidentes quanto menor o intervalo entre a aplicação e o início da alimentação das lagartas. O efeito residual do óleo de nim foi dependente da concentração utilizada, sendo que quanto maior a concentração maior o efeito residual. Os bioterápicos pouco influenciaram no desenvolvimento e na mortalidade das lagartas de A. gemmatalis. No teste de seletividade, os tratamentos bioterapicos com nosódio de A. gemmatalis e Dipel® SC, foram classificados como inócuos e o óleo de nim 0,5%, levemente nocivo, já os tratamentos com óleo de nim nas concentrações 1,5% e 2,5%, foram classificados como moderadamente nocivos

Orientador: Antônio Carlos Monteiro / Banca: José Eduardo Marcondes de Almeida / Banca: Sérgio Antonio de Bortoli / Resumo: A traça-das-crucíferas Plutella xylostella é relatada como uma das principais pragas das crucíferas no Brasil e no mundo. Sua principal forma de controle ainda é o químico, mas seu uso indiscriminado tem causado problemas de resistência de algumas populações, além de matar seus inimigos naturais e trazer malefícios para o ambiente e para o homem. Alguns estudos de controle biológico vêm sendo realizados para o controle dessa praga, dentre eles destacando-se o uso de fungos entomopatogênicos e de parasitóides. Assim, foi realizado um estudo com o objetivo de determinar a concentração e tempo letal 50 e 90 dos fungos entomopatogênicos Beauveria bassiana, Isaria fumosorosea e Metarhizium anisopliae para lagartas de P. xylostella, e a patogenicidade de isolados deste fungos para ovos, lagartas, pupas e adultos da praga. Foram utilizados cinco isolados de cada espécie fúngica, sendo que os mais patogênicos à todas as fases do ciclo de vida do inseto foram utilizados para investigar a interação dos entomopatógenos com os parasitóides Trichogramma pretiosum e T. exiguum e com o predador Podisus nigrispinus. As CL90 para B. bassiana, I. fumosorosea e M. anisopliae foram 2 x 108, 8,65 x 107 e 1,77 x 108 conídios mL-1, respectivamente, sendo que estas foram utilizadas em todos os experimentos posteriores. Os isolados CB 75 e IBCB 133 de I. fumosorosea mostraram uma ação patogênica eficiente para ovos da praga, causando, respectivamente, 66 e 70% de mortalidade. Para a fase de lagarta os isolados E9 e o IBCB 425 de M. anisopliae, causaram, respectivamente, 98 e 96% de mortes. Considerando a mortalidade total de pupas tratadas e seus adultos emergidos, a ação dos isolados AM 09, JAB 07, IBCB 74 e IBCB 87 não diferiu significativamente (p<0,01) causando, respectivamente, 94, 92, 82 e 100% de mortalidade do inseto. Para os adultos não houve diferença significativa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The diamondback moth Plutella xylostella is related as one of mainly pests in crucifers in Brazil. Its mainly control way still is chemical, but its indiscriminate use has been causing resistance in some populations, besides to kill its natural enemies and bring bad things for environment and human. Some studies of biological control have been made, outsdanding entomopathogenic fungi and parasitoids. Thus, it was determinated the lethal time and concentration 50 and 90 of entomopathogenic fungi Beauveria bassiana, Isaria fumosorosea and Metarhizium anisopliae to larvae of P. xylostella, and the pathogenicity of strains of these fungi to eggs, larvae, pupae and adults of the pest. It was used five strains of each fungal specie, and the most pathogenic were used to investigate the interaction between entomopathogens and the parasitoids Trichogramma pretiosum and T. exiguum and with the predator Podisus nigrispinus. The LC90 for B. bassiana, I. fumosorosea and M. anisopliae were 2 x 108, 8,65 x 107 e 1,77 x 108 conidia ml-1, respectively, being used in the following bioassays. The strains CB 75 and IBCB 133 of I. fumosorosea showed an efficient pathogenic action for the eggs of the pest, causing, respectively, 66 and 70% of mortality. For larvae the isolates E9 and IBCB 425 of M. anisopliae, caused, respectively, 98 and 96% of death. Considering the total mortality of treated pupae and its emerged adults, the action of AM 09, JAB 07, IBCB 74 and IBCB 87, did not differ significantly (p<0,01) causing, respectively, 94, 92, 82 e 100% of insect mortality. For adults there was no statistical difference between the B. bassiana strains. The isolates CB 75 and IBCB 133 of I. fumosorosea caused, respectively, 98 and 94% of adults death of P. xylostella and the strains E9, IBCB 159 and IBCB 425 of M. anisopliae, caused 100, 92 and 96% of death. For the obtained results in all the stages of this study... (Complete abstract click electronic access below) / Mestre

Les femelles parasitoïdes exploitant un agrégat d’hôtes doivent ajuster leurs comportements en fonction des facteurs environnementaux auxquels elles sont soumises, dont la présence de compétiteurs dans l’environnement. L’objectif de cette étude est de mesurer les impacts de la compétition sur les stratégies d’exploitation d’agrégats chez deux espèces de parasitoïdes non agressives. Les espèces Trichogramma pintoi et T. minutum (Hymenoptera : Trichogrammatidae), des parasitoïdes d’œufs de lépidoptères, furent utilisées et leurs temps de résidence dans l’agrégat, leurs mécanismes de prise de décision et le sexe des descendants alloués furent mesurés en l'absence de compétition et en situation de compétition directe et indirecte, intra- et interspécifique. Trichogramma pintoi privilégie une stratégie générale basée uniquement sur la qualité perçue de l’agrégat. À l’inverse, T. minutum privilégie une stratégie adaptée au type de la compétition (directe ou indirecte) et à la nature des compétiteurs (intra ou interspécifiques), sans égards à la qualité de l’agrégat. La distinction de ces deux stratégies amène des perspectives de recherche intéressantes sur les impacts de la compétition à l’échelle du paysage, et est d’un intérêt certain pour ceux voulant améliorer l’efficacité des programmes et des élevages de masse utilisés en lutte biologique. / Female parasitoids must adjust their behavior in response to different environmental factors when foraging for hosts. One of the most important factors they must cope with is the presence of competitors in their environment. The objective of this study is to measure the effects competition has on the foraging strategies of non-aggressive parasitoids. We used the species Trichogramma pintoi and T. minutum (Hymenoptera: Trichogrammatidae), two egg parasitoids of lepidoteran species. We measured patch residence times, patch-leaving mechanisms and progeny sex allocation of females foraging alone, and of females foraging under direct or indirect, intra- or interspecific competition. Trichogramma pintoi females favoured a general strategy entirely based on the perceived quality of the patch, whereas T. minutum females favoured a strategy that was adapted to the type of competition (direct or indirect) and to the nature of the competitors (intra- or interspecific) they were subjected to, with no regards for the quality of the patch. The distinction between these two strategies brings forth interesting research opportunities regarding the effects of competition at the landscape level, and should be of interest for biological control practitioners wishing to increase the efficacy of biological control programs and of commercial mass rearings.

Master of Science / Department of Biological & Agricultural Engineering / Naiqian Zhang / The primary objective of this research is to achieve automatic evaluation of the efficiency of using Trichogramma bourarachae for biological control of Cadra (=Ephestia) cautella by calculating the rate of parasitization. Cadra cautella is a moth feeding as a larva on dried fruit as well as stored nuts, seeds, and other warehouse foodstuffs. It attacks dates from ripening stages while on tree, throughout storage, and until consumption. These attacks cause significant qualitative and quantitative damages, which negatively affect dates’ marketability, resulting in economic losses. To achieve this research goal, tasks were accomplished by developing image processing algorithms for detecting, identifying, and differentiating between three Cadra cautella egg categories based on the success of Trichogramma parasitization against them. The egg categories were parasitized (black and dark red), fertile (unhatched yellow), and hatched (white) eggs. Color, intensity, and shape information was obtained from digital images of Cadra eggs after they were subjected to Trichogramma parasitization and used to develop detection algorithms. Two image processing methods were developed. The first method included segmentation and extractions of color and morphological features followed by watershed delineation, and is referred to as the "Watershed Method" (WT). The second method utilized the Hough Transformation to find circular objects followed by convolution filtering, and is referred to as the "Hough Transform Method" (HT). The algorithms were developed based on 2 images and then tested on more than 40 images. The WT and the HT methods achieved correct classification rates (CCRs) of parasitized eggs of 92% and 96%, respectively. Their CCRs of yellow eggs were 48% and 94%, respectively, while for white eggs the CCRs were 42% and 73%. Both methods performed satisfactorily in detecting the parasitized eggs, but the HT outperformed the WT in detecting the unparasitized eggs. The developed detection methods will enable automatic evaluation of biological control of Cadra (=Ephestia) cautella using Trichogramma bourarachae. Moreover, with few adjustments these methods can be used in similar applications such as detecting plant diseases in terms of presence of insects or their eggs.

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