The aim of this thesis was to gain an understanding of the molecular and ecological basis for the biological control of Pythium by fluorescent pseudomonads. A fluorescent pseudomonad biocontrol agent (BCA), Pseudomonas fluorescens 54/96, identified as a potential candidate for commercial development, was analysed together with transposon induced mutants in a variety of assays for anti-fungal activity (Chapter 2). It was revealed that 54/96 had a fungistatic effect generated by a number of different mechanisms, which included nutrient competition and antibiosis. The synecology of this organism with Pythium was then compared to a similar organism (P. fluorescens SBW25) demonstrating a similar degree of anti-fungal activity (Chapter 3). The similarity of the population dynamics of these two strains prompted an examination of the genetic basis for the anti-fungal activity of the second strain, with the intention of comparing with 54/96 (Chapter 4). Again this revealed a multifactorial mode of action of SBW25 against Pythium. Whilst some mutants with reduced anti-fungal activity were deficient in growth on seed exudate others were unaffected, but the mechanisms appeared to be different to those utilized by 54/96. The comparison of strains was expanded to a larger collection of pseudomonad BCAs which were contrasted by a number of phenotypic and genotypic methods (Chapter 5). Various markers were identified which showed commonality within the different classes of BCA, the most useful of which was cyclopropanated fatty acids. These may prove to be a useful marker when screening for new pseudomonad BCAs. It was concluded that a greater understanding of the molecular, physiological and ecological basis of anti-fungal activity of bacterial will lead to the development of biocontrol strategies with improved efficacy.

Doctor of Philosophy / Department of Entomology / Raymond A. Cloyd / The life history of the rove beetle, Atheta coriaria (Kraatz) (Coleoptera:Staphylinidae), predation against the fungus gnat Bradysia sp. nr. coprophila (Lintner) and compatibility with pesticides and plant growth regulators was investigated under laboratory conditions using Sunshine LC1 Professional Growing Mix as a substrate. Duration of life stages was 2.2, 7.1, and 7.8 days for egg, larva and pupa respectively, at 26°C, whereas total development time from egg to adult was 17.0 days. In addition, A. coriaria male and female adult longevity was 60.3 and 47.8 days. Average fecundity was 90.2 eggs per female and the number of adults produced per female was 69.1. There were no significant differences in prey consumption when using second and third instar fungus gnat larvae as prey and starved and non-starved rove beetles. Overall, predation efficacy in Petri dishes was high (70 to 80%) as fungus gnat larval density increased with 3.9, 7.0, 11.1, and 15.3 larvae consumed in 24 hours after exposure of 5, 10, 15 and 20 fungus gnat larvae to one rove beetle adult. However, lower predation rates were found at different predator:prey ratios when using 1 to 5 rove beetles and growing medium as a substrate. The direct and indirect effects of pesticides and plant growth regulators on A. coriaria were investigated under laboratory conditions. Rove beetle survival was consistently higher when adults were released 24 hours after rather than before applying pesticides. Acetamiprid, lambda-cyhalothrin, and cyfluthrin were directly harmful to rove beetle adults, whereas Beauveria bassiana, azadirachtin and organic oils were compatible with A. coriaria. Similarly, the plant growth regulators acymidol, paclobutrazol and uniconazole were not harmful to rove beetle adults. In addition, Beauveria bassiana, azadirachtin, kinoprene, organic oils, and the plant growth regulators did not negatively affect A. coriaria development. However, Beauveria bassiana did negatively affect rove beetle prey consumption. This study demonstrated that A. coriaria is not compatible with the pesticides acetamiprid, lambda-cyhalothrin and cyfluthrin, whereas there is compatibility with organic oils, Beauveria bassiana, azadirachtin, and the plant growth regulators. As such, these compounds may be used in combination with A. coriaria in greenhouse production systems.

Orientador: Daniel Júnior de Andrade / Resumo: O ácaro-da-ferrugem-dos-citros Phyllocoptruta oleivora é uma das principais pragas dos citros no Brasil. Os problemas atribuídos a P. oleivora têm se intensificado e suspeita-se que os danos estejam relacionados a uma nova espécie de eriofiídeo descrita recentemente, o ácaro-marrom-dos-citros Tegolophus brunneus. No entanto, não há estudos com essa espécie e informações sobre sua distribuição, características bioecológicas, danos, suscetibilidade a acaricidas e inimigos naturais associados são ausentes. O objetivo principal do projeto foi estudar a distribuição de T. brunneus na principal região citrícola brasileira e sobre as principais espécies e variedades cítricas. Além disso, estudou-se a biologia de T. brunneus em laboratório, determinou-se a suscetibilidade desse ácaro aos principais acaricidas, caracterizando seus danos em plantas cítricas, bem como o potencial de predação das principais espécies de predadores associadas ao ácaro e seu potencial para o uso no controle biológico. As coletas realizadas em vários municípios do estado São Paulo e Triângulo Mineiro demonstraram que T. brunneus infestou apenas lima ácida ‘Tahiti’, enquanto P. oleivora infestou todas as outras espécies e variedades cítricas. O ácaro completa o desenvolvimento em 7 dias, com período de incubação de 3 dias, duração de larva de 2,1 dias e de ninfa 2,8 dias e as fêmeas apresentam fecundidade de 8,5 ovos a 25°C. Os danos da espécie caracterizam-se pelo prateamento dos frutos e formação de manchas... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy School of Animal, Plant and Environmental Sciences, Johannesburg, 2014 / Water hyacinth (Eichhornia crassipes) is one of the most notorious aquatic weeds in the world. Its management, despite the release of seven biocontrol agents since 1974, remains a problem in South Africa. This is often attributed to the high level of eutrophication. However, information on the effect of heavy metals or AMD on Neochetina eichhorniae and N. bruchi, which are the common and most widely established biocontrol agents in the country, is limited. In addition integrated management, which combines herbicides with biological control methods, is the current water hyacinth control method, and requires regular monitoring of the weed’s health status. This can be assessed via the canopy chlorophyll and water content, and can facilitate the decision when to intervene and what intervention measures are appropriate and timely. Hyperspectral Remote sensing (HRS) has the potential to be that monitoring tool. This thesis investigates the physiological status of water hyacinth grown with eight different heavy metals in a single-metal tub trial, three different simulated acid mine drainage (AMD) treatments in a pool trial under the influence of biocontrol agent from Neochetina spp., and in the Vaal River at the inlets of its tributaries, the Koekemoerspruit and the Schoonspruit. A hand-held spectrometer, the analytic spectral device (ASD), was used to measure reflectance. The hypothesis that HRS can detect the response of the plant to both the heavy metals and the biocontrol-induced stresses and their interactions was tested. Different spectral indices associated with the canopy chlorophyll and water content of water hyacinth were evaluated. Among these the modified normalized difference vegetation index (mNDVI) and those associated with the red edge position (the linear extrapolation and the maximum first derivative indices) were able to detect the metal, or AMD or weevil-induced plant health stresses and showed a strong positive correlation with the actual leaf chlorophyll content, measured by a SPAD-502 chlorophyll meter. Among the contaminants Cu, Hg, and Zn treatments from the single-metal tub trial and sulphate concentrations exceeding 700 mg/L in the AMD pool trial were detected by the RS as stressful to the plants. The RS also indicated that the water contamination level was greater downstream at the inlet of the Schoonspruit into the Vaal River, compared to the other sites after rainfall. These results were also consistent with actual measurements of the different plant growth parameters in all the trials and the weevils’ feeding and reproductive activities in the tub and pool trials. Thus, the results of this study indicated that the HRS has potential as a tool to assess the physiological status of water hyacinth from a remote position, which could be helpful in management of a serious national problem. The acquisition of spectral reflectance data at a larger scale, from aerial platforms, involves a complex data set with additional atmospheric interference that can mask the reflectance and which demands more complicated image analysis and interpretation. Thus, further such studies in future are recommended.

A major concern in animal production is the occurrence of hematophagous organisms, as ticks and poultry mites. The control of these organisms is usually done with chemicals. However, this technique is being discouraged in several countries. An alternative measure is biological control. It is known that most mites of the cohort Gamasina (order Mesostigmata) are predators and their diversity and prevalence in places where ticks and poultry mites cause problems are poorly understood. One of the first recommended steps in a biological control program is to determine the fauna where the pest organisms are to be controlled. The objectives of this study were to determine the Gamasina co-occurring with Ixodes ricinus (L.) in pastures in Norway and prospect possible edaphic predatory mites of that group in Brazil to control ticks and poultry mites. In this study, 2,900 Gamasina of 12 families were collected in Norway, co-occurring with I. ricinus. The most abundant families were Parasitidae (46.9%) and Veigaiidae (25.9%), while the most diverse were Laelapidae, Macrochelidae, Parasitidae and Zerconidae, each with five species. Among these mites, a new laelapid species of Cosmolaelaps was found and is here described. In Brazil, 551 gamasines assigned to 11 families were collected and tested for their potential to feed on larvae and eggs of two tick species, Amblyomma sculptum Berlese and Rhipicephalus microplus (Canestrini), and all stages of the red poultry mite, Dermanyssus gallinae (De Geer). The most abundant families were Ologamasidae (25.4%) and Parasitidae (21.1%), while the most diverse (in terms of genera) were Ologamasidae and Laelapidae, with five and four genera, respectively. Of the evaluated predators, only Stratiolaelaps scimitus (Womersley) fed on the larvae of both tick species and all stages of D. gallinae. / Uma das principais preocupações ao longo do processo de produção animal é a ocorrência de organismos hematófagos, como carrapatos e piolhinhos. O controle destes organismos usualmente é feito com produtos químicos. Porém, esta técnica de controle vem sendo desencorajada em diversos países. Uma forma alternativa é o controle biológico. Sabe-se que a maioria dos ácaros do grupo Gamasina (ordem Mesostigmata) são de hábito predador, porém sua diversidade e prevalência nos locais em que carrapatos e piolhinhos causam problemas são pouco conhecidas. Um dos primeiros passos recomendados num programa de controle biológico é a determinação da fauna no local onde deseja-se o controle dos organismos praga. Os objetivos deste estudo foram a determinação dos Gamasina que co-ocorrem com Ixodes ricninus (L.) em pastagens na Noruega e a busca por possíveis ácaros predadores edáficos daquele grupo no Brasil, para controle de carrapatos e piolhinhos. No presente estudo, 2900 Gamasina afiliados à 12 famílias foram coletados na Noruega, co-ocorrendo com I. ricinus. As famílias mais numerosas foram Parasitidae (46,9%) e Veigaiidae (25,9%), enquanto que as mais diversas foram Laelapidae, Macrochelidae, Parasitidae e Zerconidae, cada uma com cinco espécies. Dentre estes ácaros, um novo laelapídeo do gênero Cosmolaelaps é descrito da Noruega. No Brasil, foram testados 551 Gamasina afiliados a 11 famílias, incluindo Laelapidae, Macrochelidae, Parasitidae e Veigaiidae, os quais foram testados quanto ao seu potencial em alimentar-se de larvas e ovos dos carrapatos Amblyomma sculptum Berlese e Rhipicephalus microplus (Canestrini), e de todos os estágios do piolhinho-de- galinha, Dermanyssus gallinae (De Geer). As famílias mais abundantes foram Ologamasidae (25,4 %) e Parasitidae (21,1%), enquanto as mais diversas (em termos de gênero) foram Ologamasidae e Laelapidae, com cinco e quatro gêneros, respectivamente. Dos predadores avaliados, apenas Stratiolaelaps scimitus (Womersley) alimentou-se das larvas de ambas espécies de carrapatos e de todos os estágios de desenvolvimento de D. gallinae.

O ácaro Aceria guerreronis Keifer representa uma das principais pragas da cultura do coqueiro em diversos países. Colônias deste ácaro, também designado de ácaro-do-coqueiro, são encontradas principalmente sob as brácteas dos frutos jovens, onde se alimentam de tecidos meristemáticos, freqüentemente causando queda prematura de frutos. O objetivo deste trabalho foi estimar os níveis de ocorrência de A. guerreronis e de outros ácaros a ele associados, para se avaliar o possível papel dos ácaros predadores no controle deste ácaro. Amostras foram coletadas em julho e dezembro de 2009 e abril de 2010 de 2 plantios de cada um dos seguintes municípios do Estado de São Paulo: Cedral, Mirandópolis, Riolândia e Tupã (região noroeste), e Peruíbe (litoral). Em cada campo, cada amostra consistiu de 10 frutos jovens, 30 folíolos e 5 espiguetas de inflorescência, tomados de cada uma de 5 plantas; além disso, até 10 frutos abortados foram também coletados de cada campo, quando presentes. Foram encontrados ácaros em todas as estruturas vegetais amostradas, predominando os ácaros fitófagos, que representaram 98,4% dos ácaros coletados; o restante dos ácaros, incluídos em grupos designados como predominantemente predadores e de hábitos alimentares variados representaram 0,7 e 0,9% do total, respectivamente. A densidade média de A. guerreronis (110,0 ácaros por fruto) correspondeu a aproximadamente 1/10 dos níveis comumente relatados no nordeste do Brasil. Os ácaros predadores predominantes foram Proctolaelaps bulbosus Moraes, Reis & Gondim Jr. e Proctolaelaps bickleyi (Bram), nos frutos; Iphiseiodes zuluagai Denmark & Muma e Euseius citrifolius Denmark & Muma, nos folíolos; E. citrifolius, P. bickleyi e Typhlodromalus peregrinus (Muma), nas inflorescências; e P. bulbosus e P. bickleyi, nos frutos abortados; estes entretanto ocorreram sempre em baixos níveis populacionais (não mais que 2 ácaros por 100 frutos, 4 ácaros por 100 folíolos, 3 ácaros por 100 espiguetas de inflorescência e 5 ácaros por fruto abortado). Neoseiulus baraki (Athias-Henriot) e Neoseiulus paspalivorus (De Leon), dois dos principais predadores de A. guerreronis na região nordeste e em outros países, não foram encontrados. Os resultados não permitem concluir que os baixos níveis populacionais de A. guerreronis no Estado de São Paulo sejam devidos à ação de seus inimigos naturais, mas que sejam pelo menos em parte devidos às condições climáticas predominantes ao longo do ano na região em que o trabalho foi conduzido. / Aceria guerreronis Keifer is a pest of coconut in many countries. Colonies of this mite, also called the coconut mite, are mainly found underneath the bracts of young fruits, where they feed on meristematic tissues, often causing premature fruit drop. The aim of this study was to estimate the level of occurrence of A. guerreronis and other mites associated with it, to evaluate the possible role of predatory mites in controlling this mite. Samples were collected in July and December 2009 and April 2010 from 2 plantations of each of the following municipalities of São Paulo State: Cedral, Mirandópolis, Riolândia and Tupã (northwest), and Peruíbe (coast side). In each field, each sample consisted of 10 young fruits, 30 leaves and 5 spikelets of inflorescences, taken from each of 5 plants; in addition, up to 10 aborted fruits were also collected from each field, when present. Mites were found in all plant structures sampled; predominant mites were phytophagous, which accounted for 98.4% of the species collected; the remaining mites, included in the groups designated as \"predominantly predatory\" and \"of varied feeding habit\" accounted for 0.7 and 0.9% of the total, respectively. The average density of A. guerreronis (110,0 mites per fruit) accounted for approximately one tenth of the levels commonly reported in northeast Brazil. The main predators were Proctolaelaps bulbosus Moraes, Reis & Gondim Jr. and Proctolaelaps bickleyi (Bram), on fruits; Iphiseiodes zuluagai Denmark & Muma e Euseius citrifolius Denmark & Muma, on leaflets; E. citrifolius, P. bickleyi and Typhlodromalus peregrinus (Muma), on the inflorescences; and P. bulbosus and P. bickleyi on aborted fruits; these however were always found at low levels (not more than 2 per 100 fruits, 4 per 100 leaflets, 3 per 100 spikelets and 5 per 10 aborted fruit). Neoseiulus baraki (Athias-Henriot) and Neoseiulus paspalivorus (De Leon), two major predators of A. guerreronis in the northeast and in other countries, were not found. The results do not suggest that the low levels of A. guerreronis in São Paulo are due to the action of natural enemies, but they are at least partly due to climatic conditions prevailing during the year in the region where the study was conducted.

Ainda é pequena a disponibilidade de agentes de controle biológico no Brasil. Isso se deve em parte à dificuldade de produção destes, o que frequentemente inviabiliza seu uso. Os ácaros da família Phytoseiidae estão entre os predadores mais utilizados como agentes de controle biológico de ácaros e de pequenos insetos pragas. Atualmente, a criação daqueles agentes é feita principalmente sobre plantas infestadas com presas naturais. Este tipo de criação, apesar de eficiente, demanda grandes áreas, o que aumenta o custo de produção. Para facilitar a produção, alimentos alternativos têm sido avaliados. O objetivo deste trabalho foi determinar alimentos alternativos para a produção massal dos fitoseídeos Amblyseius tamatavensis Blommers, Euseius concordis (Chant) e Neoseiulus anonymus (Chant e Baker). Inicialmente realizou-se um teste de oviposição com 15 espécies de ácaros Astigmatina, cinco tipos de pólen e uma espécie de nematoide. Amblyseius tamatavensis foi o único que apresentou níveis satisfatórios de oviposição quando alimentado com ácaros Astigmatina, atingindo 2,6 ovos/fêmea/dia quando alimentado com Thyreophagus n. sp. e 2,1 ovos/fêmea/dia quando alimentado com Aleuroglyphus ovatus (Troupeau, 1879). Dentre os tipos de pólen, o de Ricinus communis L. proporcionou os maiores níveis de oviposição, sendo de 1,7 e 1,2 ovos/fêmea/dia para E. concordis e A. tamatavensis, respectivamente. Neoseiulus anonymus não apresentou níveis satisfatórios de oviposição para nenhum dos tipos de pólen avaliados. Em relação ao nematoide (Protohabditis sp.) apenas A. tamatavensis apresentou nível de oviposição satisfatória, sendo este de 1,2 ovos/fêmea/dia. Com base nestes resultados, optou-se por elaborar uma tabela de vida de fertilidade apenas para A. tamatavensis alimentado com as duas espécies de Astigmatina citados anteriormente. Assim como no teste de oviposição, o melhor desempenho foi obtido com A. tamatavensis alimentado com Thyreophagus n. sp., obtendo níveis satisfatórios de rm (0,19), T (12,8), Ro (11,47) e λ (1,2). Considerando-se os resultados promissores obtidos, iniciou-se um teste preliminar de criação massal de A. tamatavensis utilizando o método descrito por Freire e Moraes (2007). Em uma criação com população inicial de 200 ácaros, o número de predadores aumentou em média 34 vezes após 30 dias. Este resultado mostrou que A. tamatavensis tem grande potencial para ser criado de forma massal com o uso de Thyreophagus n. sp. / The availability of biological control agents in Brazil is still low. This is due in part to the difficulties found in the production of those organisms, which often hampers their use. Phytoseiidae is a family of predatory mites commonly used as biological control agents of mite and small insect pests. Currently, these agents are mainly reared on infested plants with their natural prey. This type of rearing, although efficient, requires large areas, which increases production cost. To facilitate production, alternative food sources have been used. The aim of this study was to determine alternative food for mass production of the phytoseiids Amblyseius tamatavensis Blommers, Euseius concordis (Chant) and Neoseiulus anonymus (Chant and Baker). Initially, an oviposition test was conducted with 15 mite species of the cohort Astigmatina, five types of pollen and one species of bacteriophagous nematode. Amblyseius tamatavensis was the only one that presented satisfactory levels of oviposition when fed with astigmatins, reaching 2.6 eggs/female/day when fed with Thyreophagus n. sp. and 2.1 eggs/female/day when fed with Aleuroglyphus ovatus (Troupeau, 1879). Among the types of pollen, Ricinus communis L. induced the highest levels of oviposition, reaching 1.7 to 1.2 eggs/female/day for E. concordis and A. tamatavensis, respectively. Neoseiulus anonymus did not have satisfactory levels of oviposition on any type of pollen. Regarding the nematode (Protohabditis sp.), only A. tamatavensis had satisfactory level of oviposition on this prey (1.2 eggs/female/day). Based on these results, fertility life tables were constructed only for A. tamatavensis fed with Thyreophagus n. sp. and with A. ovatus. As in the oviposition test, the best performance was obtained with Thyreophagus n. sp., on which the following life table parameters were obtained: rm (0.19), T (12.8), Ro (11.47) and λ (1.2). Considering these promising results, a preliminary test for the mass rearing of A. tamatavensis was initiated using the method described by Freire and Moraes (2007). When 200 predators were initially introduced to each rearing unit, the number of predators increased 34 times within 30 days. This result indicated that A. tamatavensis may be mass produced with the use of Thyreophagus n. sp. as prey.

Myriophyllum spicatum L. (Haloragaceae), a submerged macrophyte, has been recorded in southern Africa since 1829, but only considered problematic as recently as 2005. In light of this, water resource managers are looking to control M. spicatum in southern African water bodies where it is problematic. Amongst control options available in South Africa, biological control is potentially the most cost effective and sustainable option for M. spicatum. However, there is a debate over the status of this plant in southern Africa with several authors reporting it as a native component of the aquatic ecosystem, while others argue that it has been introduced from Europe or Asia. The aim of this thesis is to use a multifaceted approach to resolve the status of M. spicatum, by studying aspects of its history, distribution, mechanisms of its adaptations, biotic interactions and genetic relationships in southern Africa. By resolving the status of this plant as either native or exotic, appropriate management strategies can be initiated for its control in situations where it is considered a problem.A review of the evidence collected from this thesis does not provide convincing evidence for the anthropogenic introduction of M. spicatum into southern Africa, and it is probably native to the region. The disjunct distribution as well as regular local extinctions of populations is relatively common for species that are at the edge of their range. The populations in southern Africa could thus be relics from a much wider distribution in the past. The development of local adaptations in southern Africa provides evidence for this and suggests that the populations have been isolated for a substantial period of time and have had a long evolutionary history in the region. The lack of specialist herbivores should suggest that M. spicatum has been introduced, but the complete lack of herbivores, including generalists, may weaken that argument. The lack of herbivores could be a result of something inherent in the plant, irrespective of a lack of evolutionary history in the region. The genetic evidence suggests a European origin, but is characteristic of a population (southern Africa as a whole) that has been isolated for a considerable time. Despite the findings of this research, M. spicatum is considered problematic in southern Africa and warrants control in certain systems. Whether or not biological control should be a component of the management strategy is open to further debate. The benefits in a southern African context may outweigh the risks, based on the specificity of the biological control agent proposed. However, the perceived negative impacts of M. spicatum are likely to be a symptom of a more serious underlying cause, such as nutrient loading and changes in land use patterns. Therefore the control of this native species is a water resource management issue and not a biological control issue.

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Apesar de o Brasil ser um dos principais produtores de laranja no mundo e o maior exportador de suco concentrado, atualmente a cultura vem sofrendo perdas em razão do ataque de diversas pragas e doenças, sendo a principal o Huanglongbing (HLB), ou Greening, que foi relatada pela primeira vez em 2004 no estado de São Paulo. Essa doença está associada às bactérias do gênero \"Candidatus Liberibacter sp.\", sendo que no Brasil ocorrem as bactérias \"Ca. Liberibacter asiaticus\" e \"Ca. Liberibacter americanus\", tendo como seus vetores o psilídeo Diaphorina citri, praga importante devido a sua distribuição geográfica e características biológicas. Existe registro de cerca de 50 espécies da família Rutaceae, que incluem as espécies do gênero Citrus (laranjas, limões, limas, etc.), que podem hospedar esse inseto, além da murta (Murraya paniculata). Na natureza, D. citri é controlado por uma série de fatores, podendo ser outros insetos, fungos ou até condições climáticas desfavoráveis para seu desenvolvimento. Porém, os resultados de pesquisas indicam que ectoparasitoide Tamarixia radiata é eficiente no controle de D. citri. Entretanto, levantamentos realizados nos últimos anos verificaram que o parasitismo natural vem sendo reduzido consideravelmente, devido, principalmente, à aplicação intensiva de agroquímicos. Dessa forma, a utilização de produtos seletivos, ou seja, que atue contra o psilídeo D. citri e tenha o menor impacto possível sobre o parasitoide T. radiata é imprescindível para o sucesso do manejo integrado de pragas em que se utiliza o controle químico juntamente com a liberação do parasitoide. Assim, objetivou-se com esse trabalho: 1) Estudar o efeito direto e a persistência de inseticidas sobre o parasitoide T. radiata; 2) Estudar o efeito de inseticidas sobre a fase pupal do parasitoide; 3) Determinar a interferência dos inseticidas na capacidade de parasitismo; 4) Avaliar a toxicidade diferencial dos inseticidas para o parasitoide T. radiata e para o psilídeo D. citri. Dos 25 inseticidas testados no efeito direto, 20% foram considerados inócuos (classe 1); 12% levemente nocivo (classe 2); 12% moderadamente nocivo (classe 3); e 56% como nocivo (classe 4). Apesar de vários serem nocivos para adultos do parasitoide, apenas Lorsban® 480 BR e Perfekthion® afetaram a emergência do parasitoide quando pulverizados sobre a sua fase de pupa, sendo que os demais permitiram a emergência e não afetaram a duração, razão sexual e longevidade. No teste de persistência, 25% dos inseticidas testados foram considerados de vida curta (classe 1); 37,5% como levemente persistentes (classe 2); 29,2% moderadamente persistentes (classe 3); e apenas 8,3% persistentes (classe 4). Portanto, para a escolha de um inseticida para controle de pragas dos citros, deve-se levar em consideração seu efeito no adulto, fase imatura e sua persistência biológica na planta. / Although Brazil is one of the major orange producers and largest exporter of juice concentrate in the world, currently the citrus culture suffers losses due to the attack of several pests and diseases. Huanglongbing (HLB), or Greening, is the main disease and it was first reported in 2004 in the State of São Paulo, Brazil. This disease is associated with bacteria of the genus \"Candidatus Liberibacter sp.\", and in Brazil the bacteria \"Ca. Liberibacter asiaticus\" and \"Ca. Liberibacter americanus\" occur, and the psyllid Diaphorina citri is its main vector, an important pest insect because of its geographical distribution and biological characteristics. There is record of about 50 species of the family Rutaceae, including the species of the genus Citrus (oranges, lemons, limes, etc.) that can host this insect, in addition to orange jasmine (Murraya paniculata). In nature, a number of factors control D. citri, namely other insects, fungi or even adverse weather conditions for their development. However, studies show that the ectoparasitoid Tamarixia radiata is efficient in the control of D. citri. However, recent studies indicate that natural parasitism has been reduced considerably, mainly due to the intensive application of pesticides. Thus, the use of selective products, i.e., which act against the psyllid D. citri with the lowest possible impact on the parasitoids T. radiata is indispensable for the success of the integrated pest management that uses chemical control along with the release of parasitoids. Thus, the objectives of this work were: 1) to study the direct effect and the persistence of insecticides on the parasitoid T. radiata; 2) to investigate the effect of insecticides on the pupal stage of the parasitoids; 3) to determine the effect of insecticides on parasitism capacity; 4) to assess the differential toxicity of insecticides to the parasitoid T. radiata and psyllid D. citri. Of the 25 insecticides tested in terms of direct effect, 20% was considered harmless (class 1); 12% slightly harmful (class 2); 12% moderately harmful (class 3); and 56% as harmful (class 4). Although several are harmful to adult of the parasitoid, only Lorsban® 480 BR and Perfekthion® affected the emergence of the parasitoid when sprayed in the pupal stage, and the others allowed the emergence and did not affect the duration, sex ratio and life span. In the test of persistence, 25% of the insecticides were considered short life (class 1); 37.5% slightly persistent (class 2); 29.2% moderately persistent (class 3); and only 8.3% persistent (class 4). Therefore, choosing an insecticide for control of pests of citrus requires consideration of its effect on adults, immature phase and their biological persistence in the plant.