Introdução: Após alguns anos possivelmente ausente do Brasil, o Ae. aegypti, principal transmissor dos vírus da dengue volta a ser encontrado, sendo este fato comprovado no Estado de São Paulo desde 1985. No município de Santos focos de Ae. aegypti foram assinalados em 1980, todavia a sua infestação foi comprovada em 1994 (SUCEN). Os primeiros casos de dengue autóctones (contraídos no município de Santos) emergiram no início de 1997. O objeto de estudo desse trabalho é a dengue no município de Santos e sua transmissão que parece ininterrupta. Objetivo: estudar a ocorrência da dengue no município de Santos no período de 1997 a 2008 em alguns de seus aspectos epidemiológicos, clínicos e vetoriais e possíveis causas da flutuação das epidemias1 consecutivas permeadas por períodos de surtos epidêmicos2. Método: Estudo descritivo com análise comparativa entre os índices de infestação do Aedes com a incidência3 da dengue no mesmo período para avaliar se houve impacto das ações de controle. As variáveis para a análise de incidência serão somente os casos notificados, confirmados e residentes em Santos nos anos de 1997 a 2008, por faixa etária, sexo, ano e mês de ocorrência. Resultados: A incidência acumulada da doença de aproximadamente 84% pode apontar para uma possível diminuição de suscetíveis para os três sorotipos (1, 2 e 3), e o risco de novas epidemias é possível, seja com a introdução do sorotipo 4, onde toda a população é suscetível, aumentando o risco dos casos de dengue hemorrágica, ou epidemias infantis, atingindo em maior número lactantes e crianças até 14 anos, uma vez que a prevalência é menor. Conclusões: O comportamento da incidência da dengue durante esses doze anos consecutivos de autoctonia no município de Santos mostrou como característica principal a ciclotimia, anos epidêmicos intercalados com surtos, possível esgotamento de suscetíveis adultos para cada novo vírus introduzido, e os métodos utilizados no controle da doença mostraram que não foram suficientes, embora legitimamente embasados, faltou a integração das ações, com planejamento, acompanhamento e avaliação / Introduction: After a few years away from possibly Brazil, Ae. aegypti, the main transmitter of the dengue virus is again found, and this was proven in the State of São Paulo since 1985. In the city of Santos foci of Ae. aegypti was reported in 1980, but its infestation was confirmed in 1994 (SUCEN). The first cases of indigenous dengue fever (contracted in the city of Santos) re-emerged in early 1997. The object of this paper is to study dengue in the city of Santos and its transmission that seems unbroken. Objective: To study the incidence of dengue in the city of Santos in the period 1997 to 2008 in some of its epidemiological, clinical and vector and possible causes of fluctuations in consecutive epidemics1 interspersed by periods of epidemic outbreaks2. Method: A descriptive and comparative analysis between the infestation levels of Aedes with the incidence3 of dengue in the same period to assess whether there was impact of control measures. The variables for the incidence analysis will only be notified cases confirmed and living in Santos in 1997 and 2008, by age, sex, year and month of occurrence. Results: The prevalence of the disease approximately 84% can point to a possible reduction of susceptibility to the three serotypes (1, 2 and 3), and the risk of new epidemics are possible, either with the introduction of serotype 4, where the entire population is susceptible, increasing the risk of cases of dengue hemorrhagic fever, epidemic or \"childish\", reaching in many infants and children up to 14 years, since the prevalence is lower. Conclusions: The behavior of the incidence of dengue during these twelve consecutive years of autochthony the city of Santos showed the main characteristic of cyclothymia, interspersed with years epidemic outbreaks, depletion of susceptible adults for each new virus introduced, and the methods used to control the disease showed that there were sufficient, although legitimately grounded, lacked the integration of action, with planning, monitoring and evaluation

Research trials performed in the greenhouse compared the tolerance and response of Hordeum jubatum and desirable pasture grass species to herbicides, salinity, and flooding. Desirable grass species used in this study included: `Fawn' tall fescue (Festuca arundinaceae), `Garrison' creeping foxtail (Alopecurus arundinaceus), `Palaton' reed canarygrass (Phalaris arundinacea), `Climax' timothy (Phleum pratense), `Alkar' tall wheatgrass (Thinopyrum ponticum), `Potomac' orchardgrass (Dactylis glomerata), and `Mustang' altai wildrye (Leymus angustus). Tolerance to herbicides, salinity, and flooding varied significantly among grass species. Herbicide tolerance was tested using four herbicides at five rates each. The herbicides used were imazapic (Plateau), propoxycarbazone (Olympus), sulfosulfuron (Outrider), and flucarbazone (Everest) at rates of 0, 10, 25, 50, 100, and 200 g ha-1. Foxtail barley was least tolerant of sulfosulfuron and propoxycarbazone. Tall fescue, creeping foxtail, and reed canarygrass were susceptible to all the herbicides tested. Timothy and foxtail barley were moderately tolerant while tall wheatgrass exhibited the greatest tolerance to flucarbazone. Orchardgrass was most tolerant to propoxycarbazone. Salinity tolerance was determined by exposing grasses to increasing electrical conductivity (EC) over time. Reed canarygrass and timothy were most susceptible to salinity. Orchardgrass, creeping foxtail, and tall fescue were moderately tolerant of salinity. Foxtail barley, altai wildrye, and tall wheatgrass exhibited the highest tolerances to salinity, and continued to persist at the highest EC levels tested. Flooding tolerance was determined by flooding grasses in 18 cm of water for 2, 4, 6, and 8 weeks. Grasses that were able to extend above the water surface survived, whereas plants that failed to extend beyond the water surface experienced higher mortality rates.

No description available.

The public concern over synthetic pesticides in foods and the environment has created an interest to find effective and safe non-fungicide means of controlling postharvest pathogens. The overall objective of this thesis was to evaluate the effect of potassium silicate, yeast antagonists and hot water dip treatment to control postharvest grey mould and blue mould of pome fruits, caused by Botrytis cinerea and Penicillium expansum, respectively. Botrytis cinerea and Penicillium expansum were isolated from infected strawberry and pear fruits, respectively. These isolates were found to be non-resistant to YieldPlus® (Anchor yeast, Cape Town, South Africa), a biofungicide containing a yeast Cryptococcus albidus. A total of 100 epiphytic yeast isolates were obtained from the fruit surface of “Golden Delicious” apples and “Packham’s Triumph” pears, and screened against B. cinerea and P. expansum. Fifteen yeast isolates reduced grey mould incidence by > 50%, when applied four hours before inoculation with B. cinerea. Similarly, seven yeast isolates reduced blue mould incidence by > 50%, when applied four hours before inoculation with P. expansum. YieldPlus® and yeast Isolate YP25 provided the best control of B. cinerea, while Isolate YP60 and YieldPlus® provided the best control of P. expansum on “Golden Delicious” apples. A mixture of YP25 and YP60 provided complete control of both B. cinerea and P. expansum, when applied to “Golden Delicious” apples before inoculation with either B. cinerea or P. expansum. Electron microscopy studies showed that yeast Isolates YP25 and YP60 inhibited the mycelial growth of B. cinerea and P. expansum, respectively. Preventative and curative application of potassium silicate resulted in reduced incidence of B. cinerea or P. expansum of “Golden Delicious” apples. Electron microscopy studies indicated that potassium silicate inhibited the growth of B. cinerea and P. expansum. Furthermore, treatment of “Golden Delicious” apples with either potassium chloride or potassium hydroxide resulted in reduced incidence of both B. cinerea and P. expansum. In vivo tests showed that the disease incidence of P. expansum and B. cinerea on “Golden Delicious” apples was reduced by hot water dip treatments at 58-60°C for 60 to 120 seconds, compared with the control fruit treated with sterile distilled water, without causing skin damage. The use of potassium silicate, yeasts (Isolates YP25 and YP60), YieldPlus® and the antagonists mixture (YP25+YP60) in combination, resulted in the control of B. cinerea and P. expansum of “Golden Delicious” apples compared with Imazalil® treated fruit. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

In the genus Fusarium are many important plant pathogens. The diversity of hosts the genus attacks, the number of pathogenic taxa and the range of habitats in which they cause disease are the greatest in plant pathology. One important species complex within the genus Fusarium is Fusarium oxysporum Schlecht. This species complex consists more than 80 pathogenic forma specialis and is particularly difficult to control. The fungi can survive in soil for decades as specialized spores, known as chlamydospores. Interestingly, however, this species complex also contains beneficial non-pathogenic forms that can be exploited to manage Fusarium wilt diseases. In this study, the ability of non-pathogenic F. oxysporum strains, Trichoderma harzianum Rifai Eco-T®, soluble silicon, and their combination was evaluated on two important crops, banana (Musa sp. L.) and beans (Phaseolus vulgaris L.), for their potential to suppress pathogenic strains of F. oxysporum. The ability of these crops to take up and accumulate silicon in their organs, and its effect on low temperature stress was also investigated. Several endophytic fungi, mainly Fusarium spp. and bacteria, were isolated from healthy mature banana plants. After preliminary and secondary in vivo screening tests against F. oxysporum f.sp. phaseoli on beans (Phaseolus vulgaris L.) cv. Outeniqua, two non-pathogenic F. oxysporum strains were selected for further testing. These two non-pathogenic F. oxysporum strains were found to colonize banana (Musa sp.) cv. Cavendish Williams and bean plants, and to suppress Fusarium wilt of these crops. In order to improve the efficacy of these biocontrol fungi, soluble silicon was introduced. The relationship between plant mineral nutrition and plant diseases have been reported by several authors. Plants take up silicon equivalent to some macronutrients, although it is not widely recognized as an essential element. In this study, we established that roots, the target plant organ for soilborne plant pathogens, accumulated the greatest quantity of silicon of any plant organs when fertilized with high concentrations of silicon. On the other hand, the corm and stem accumulated the least silicon. Such observations contradict the concept of passive uptake of silicon via the transpiration stream in these plants as the only uptake mechanism. The prophylactic properties of silicon have been documented for many crops against a variety of diseases. In vitro bioassay tests of silicon against these wilt pathogens showed that silicon can be toxic to Fusarium wilt fungi at high concentrations (>7840 mg .-1), resulting in complete inhibition of hyphal growth, spore germination and sporulation. However, low concentrations of silicon (<490 mg .-1) encouraged hyphal growth. Silicon fertilization of banana and beans significantly reduced disease severity of these crops by reducing the impact of the Fusarium wilt pathogens on these crops. However, it could not prevent infection of plants from the wilt pathogens on its own. Synergistic responses were obtained from combined applications of silicon and non-pathogenic F. oxysporum strains against Fusarium wilt of banana. Combinations of silicon with the non-pathogenic F. oxysporum strains significantly suppressed disease severity of Fusarium wilt of banana, caused by F. oxysporum f.sp. cubense (E.F. Smith) Snyder & Hansen, better than applications of either control measure on their own. Banana production in the subtropical regions frequently suffer from chilling injury, and from extreme variations between night and day temperatures. Such stress predisposes banana plants to Fusarium wilt disease. Silicon, on the other hand, is emerging as important mineral in the physiology of many plants, ameliorating a variety of biotic and abiotic stress factors. We established that silicon fertilization of banana plants significantly reduced chilling injury of banana plants. Membrane permeability, lipid peroxidation (MDA level) and proline levels were higher in silicon-untreated plants than the treated ones, all of which demonstrated the stress alleviating effect of silicon. Low temperatures damage the cell membrane of susceptible plants and cause desiccation or dehydration of these cells. Levels of sucrose and raffinose, recognized as cryoprotectants, were significantly higher in silicon-amended banana plants than unamended plants. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Powdery mildew (PM) is an important foliar disease of many crops, occurring under both greenhouse and field conditions. The application of biological control and soluble silicon (Si) against PM has received increasing acceptance as a result of increased environmental and public concern over the use of fungicides for disease management, and because many key fungicides are no longer effective because of resistance problems. However, success with these control options depends on the development of effective antagonists and understanding how best to use Si in agriculture. Potential antagonists of PM were isolated from naturally infected leaves of different plants. A total of 2000 isolates were tested in a preliminary screening on detached leaves of zucchini. The best 30 isolates showing consistent results were further tested under greenhouse conditions for their efficacy against PM of zucchini. In a greenhouse trial, 23 isolates provided disease control to levels of 30 to 77%. Application of 29 isolates resulted in significant reductions in values of area under disease progress curve (AUDPC). The best five isolates were identified as Clonostachys rosea (Link) Schroers, Samuels, Seifert & Gams (syn. Gliocladium roseum) (Isolate EH), Trichothecium roseum (Pers.) Link (syn. Cephalothecium roseum) (Isolate H20) and Serratia marcescens (Bizio) (Isolates B15, Y15 and Y41). Three adjuvants (Break-ThruR (BK), PartnerR (PR) and Tween-80R (T-80)) were compared for their ability to improve efficacy of spray application of silicon (Si) and biocontrol agents (BCAs) against PM. Both BK and PR improved the efficacy of Si significantly (P < 0.05). Microscopic studies showed that BK affected PM fungi directly and enhanced the deposition of BCAs on the pathogen. Break-ThruR was only toxic to the pathogen mycelia when used at > 0.25 m. .-1, but phytotoxic to zucchini plants when used at > 0.45m. .-1. However, it did not affect the c.f.u. of bacterial BCAs. Use of BK at 0.2-0.4 m. .-1 can be recommended to assist spray application of Si (at 750 mg .-1) or BCAs for improved control of PM. The effect of concentration, frequency of application and runoff of Si sprays applied to the foliage was evaluated for control of PM of zucchini. Silicon (250-1000 mg .-1) + BK (0.25 m. .-1), was sprayed onto zucchini plants at frequencies of 1-3 wk-1. Spraying Si reduced the severity of PM significantly (P < 0.05). Regardless of the concentration of Si, the best results were obtained when the frequency of the treatment was increased, and when spray drift or spray runoff were allowed to reach the rhizosphere of the plants. When Si was applied onto leaves, direct contact between the spray and the pathogen resulted in mycelial death. Part of the spray (i.e., drift and runoff) was absorbed by plant roots, and subsequently played an important role in the health of the plants. If affordable, soluble Si should be included in nutrient solutions of hydroponics or supplied with overhead irrigation schemes when PM susceptible crops are grown. Under greenhouse conditions, application of BCAs, with or without Si, reduced the severity and development of PM significantly (P < 0.001). Application of Si significantly reduced the severity and AUDPC values of PM (P < 0.05 for both parameters). Silicon alone reduced the final disease level and AUDPC values of PM by 23-32%, and improved the efficacy of most BCAs. In the course of the investigation, antagonistic fungi consistently provided superior performances to bacterial isolates, providing disease control levels of up to 90%. Higher overall disease levels reduced the efficacy of Si against PM, but did not affect the efficacy of BCAs. Under field conditions, Si alone reduced disease by 32-70%, Isolate B15 reduced disease by 30-53% and Isolate B15 + Si reduced disease by 33-65%. Other BCAs applied alone or together with Si reduced the disease level by 9-68%. Most BCAs reduced AUDPC values of PM significantly. For most antagonists, better efficacy was obtained when Si was drenched into the rhizosphere of the plant. However, efficacy of some of the BCAs and Si were affected by environmental conditions in the field. Repeated trials and better understanding of how to use Si and the BCAs, in terms of their concentration and application frequency, and their interactions with the plant and the environment, are needed before they can be used for the commercial control of PM. Elemental analysis was conducted to determine the impact of differing application levels of silicon (Si) in a form of potassium silicate (KSi) in solution in terms of Si accumulation and selected elements in different tissues of zucchini and zinnia and growth of these plants, and to study the effect of PM on the levels of selected elements in these two plant species. Plants were grown in re-circulating nutrient solutions supplied with Si at different concentrations and elemental composition in different parts were analysed using EDX and ICP-OES. Increased levels of Si in the solution increased the levels of Si in leaves and roots of both plants without affecting its distribution to other plant parts. In zucchini, the roots accumulated the highest levels of Si, substantially more than in the shoots. In contrast with zinnia, accumulation of Si was highest in the leaves. Accumulation of potassium (K) in shoots of both plants increased with increased levels of KSi in the nutrient solution. However, K levels in flower of zinnia, fruits of zucchini and roots of both plants remained unaffected. Increased level of Si reduced accumulation of calcium (Ca) in both plants. Adding Si into the nutrient solution at 50 mg .-1 resulted in increased growth of zucchini and increased uptake of P, Ca, and Mg by both plant species. However, application of higher levels of Si did not result in any further biomass increase in zucchini. Levels of Si in the nutrient solution had no effects on elemental composition and characteristics of the fruits of zucchini. In both plant species, the presence of PM on the leaves of plants resulted in these leaves accumulating higher levels of Si and Ca, but less P, than leaves of uninfected plants exposed to the same levels of soluble Si. The highest concentrations of Si were observed in leaf areas infected with PM, and around the bases of trichomes. For optimum disease control and maximum accumulation of different elements in these two plants, hydroponic applications of Si at 50-150 mg .-1 is recommended. Five selected biocontrol agents and potassium silicate, used as source of soluble Si, were tested under hydroponic conditions at various concentrations against PM of zinnia (Glovinomyces cichoracearum (DC) Gelyuta, V.P.). Application of BCAs resulted in reductions in final disease level and AUDPC values of PM by 38-68% and 30-65%, respectively. Both severity and AUDPC values of PM were reduced by 87-95% when plants were supplied with Si (50-200 mg .-1). It is proposed that the provision of a continuous supply of Si and the ability of this plant species to accumulate high levels of Si in its leaves were the major reasons for the good response of zinnia to Si treatments against PM. Silicon played a protective role before infection and suppressed development of PM after infection. The combination of the best selected BCAs and Si can be used as an effective control option against PM of zinnia when grown in hydroponic system. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Plant health system is an important element for the control and management of plant pests to ensure food production and security as well as safe trade. The objectives of this study were to: identify the existing knowledge gaps on current plant health system at the national and provincial level, identify critical areas to be addressed in the current plant health institutional framework and identify the existing limitations and risks on current legislation. A semi-structured questionnaire was used to collect the data. The data was analysed statistically using the one-way frequency and Spearman’s Rank correlation coefficients.The study found that the Provincial Departments of Agriculture (PDAs) (below 50%) lack knowledge of plant health system as compared to the national authorities: DAFF and DEA (above 70%). The study also found that there were no formal linkages between the national and provincial authorities. The study further revealed that there is a need for harmonisation of relevant legislation. It can be concluded that there are knowledge gaps on plant health matters between the national authority and the provincial level and that there are no formal linkages within the spheres of government on plant health matters. / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

This research project explores the increasingly popular phenomena of companies striving to harmonize and align their business which is called a “One Company”-vision. The project is carried out on behalf of the global IT and management consultancy company, Logica. It is a case study at Saab AB, the Swedish aerospace-and defense-company, regarding corporate strategy. In this research project, the concept of parenting style is related as one important ingredient of One Company and it is considered to be the starting point for implementation of strategy. Implementation of strategy is further illustrated with the help of a tentative model. This model puts strategy in the center of the organization and then intends to align the whole company through strategic congruence and integrated control in order to implement the chosen strategy. If the whole organization is not committed, it will be very difficult to complete the journey to become One Company. The purpose of this research project is to develop a perspective of a One Company concept and to investigate the implementation of this concept at Saab AB. To further explain the purpose and to deepen the understanding of the One Company concept, the following research questions have been addressed: How does Saab AB, a large Swedish multi-business organization, strive to become One Company? What are (if any) the critical success factors in Saab’s journey to become One Saab? What are (if any) the areas of improvement for Saab, according to the developed perspective of the One Company concept? In order to accomplish the purpose, interviews have been performed with corporate level management. Moreover, gaps have been filled with empirical findings from a dissertation that investigated Saab’s competitive advantage in relation to strategic congruence and integrated control. The results show that for Saab AB, the One Company vision started as a market initiative to create a common brand for what used to be a conglomerate. The One Saab strategy has led to many changes for Saab AB, regarding organizational structure, work methods and follow-up processes. It has affected all business areas and all functions. Human Resource and Finance are functions that have already been harmonized. Current changes concern consolidation of IT and implementation of a global management system. The global management system was launched this year (2011) and it will lead to many more changes within the company before it is fully implemented. This system will help bring the company closer to become One Saab. The conclusion is that Saab AB has come a long way but today it is a synergic corporation and not yet One Company, as the concept is described in this thesis.

O carrapato Rhipicephalus microplus é o principal ectoparasita de bovinos. O controle de R. microplus baseia-se principalmente no uso de acaricidas químicos, o que contribuiu para o problema emergente da seleção de populações de carrapatos resistentes. Portanto, há a necessidade do desenvolvimento de métodos mais eficientes/sustentáveis de controle, como o controle biológico utilizando fungos acaropatogênicos. A eficácia do fungo Metarhizium anisopliae de forma isolada ou em associação com acaricida químico para controle do carrapato bovino já foi evidenciada em condições de campo utilizando uma cepa de carrapatos resistente à acaricidas. No entanto, pouco se sabe sobre os mecanismos moleculares de R. microplus envolvidos na sua interação com M. anisopliae e com acaricidas. Assim, o objetivo do presente estudo foi avaliar a resposta de larvas de R. microplus expostas ao fungo, ao acaricida e à associação de ambos. Primeiramente foi realizado um estudo para determinar a metodologia mais indicada para avaliar o efeito in vitro do fungo M. anisopliae sobre larvas de R. microplus. Para isso, comparamos o Teste de Pacote de Larvas modificado (TPL) e o Teste de Imersão de Larvas (TIL). Os valores de tempo letal mediano (TL50) obtido na maior concentração de M. anisopliae (108conídios/mL) foram 24,8 e 9,2 dias para o TPL e TIL, respectivamente. A mortalidade após 21 dias foi de 38% e 98% para o TPL e TIL respectivamente, na mesma concentração. O TIL demonstrou ser o teste mais indicado a ser utilizado, sendo, portanto, escolhido para realização dos experimentos futuros. Em seguida foi realizado um estudo para comparar a suscetibilidade de diferentes isolados de R. microplus ao fungo M. anisopliae. Foram avaliados 67 isolados de campo. Para tanto, as larvas de R. microplus foram imersas em uma suspensão de M. anisopliae (108conídios/mL) durante 5 min. Os tempos letais medianos (TL50) variaram de 2,6 a 24,9 dias A mortalidade observada no 15º dia após o tratamento variou de 26,3 a 100% nas amostras testadas. Esses resultados demonstraram que as populações de campo de R. microplus apresentam uma alta variação em sua suscetibilidade a M. anisopliae. Por fim, foi realizada uma análise transcricional (RNAseq) de larvas de R. microplus expostas a M. anisopliae, cipermetrina, associação de ambos e do controle (não-tratado). A análise dos transcritos dos quatro grupos gerou um total de 507.792 sequências com um tamanho total de 303.160.891 pb. Foram encontrados 31 genes diferencialmente expressos no grupo controle quando comparado com M. anisopliae, 39 com cipermetrina e 73 com M. anisopliae + cipermetrina. M. anisopliae e o grupo da associação apresentaram 81 genes diferencialmente expressos e M. anisopliae e cipermetrina, 46. Houve 177 genes diferencialmente expressos ao comparar M. anisopliae + cipermetrina com larvas expostas à cipermetrina Os resultados deste estudo demonstraram que a associação M. anisopliae + cipermetrina aumentou a expressão de genes relacionados a resposta à agressão, provavelmente pelo fato da associação provocar uma agressão maior ao carrapato e este responder de forma mais rápida, levando à superexpressão de genes de defesa. As descobertas deste estudo fornecem informações sobre as vias e mecanismos moleculares de R. microplus ativados em resposta à interação de M. anisopliae e a acaricida. Além disso, esses estudos estabelecem as bases para pesquisas futuras sobre genes-chave que controlam a suscetibilidade de R. microplus a M. anisopliae. O sinergismo evidenciado em nossos estudos comprova a ideia de que o controle integrado, utilizando o controle biológico com o controle químico é uma opção tanto para o controle de cepas de carrapatos resistentes à acaricidas, quanto para um controle mais rápido de cepas de carrapatos que não apresentam resistência ou que apresentem resistência intermediária. / The tick Rhipicephalus microplus is the major cattle ectoparasite. The control of R. microplus is based mainly on the use of chemical acaricides, which contributed to the emerging problem of the selection of tick populations resistant to acaricides. Therefore, there is a need for the development of more efficient/sustainable methods of control, such as biological control using acari pathogenic fungi. The effectiveness of the fungus Metarhizium anisopliae alone or in association with chemical acaricide to control the bovine tick has already been evidenced under field conditions using an acaricide resistant tick strain. However, to date, little is known about the molecular pathways of R. microplus involved with its interaction with M. anisopliae and with acaricides. Thus, the aim of the present study is to evaluate the response of R. microplus larvae exposed to the fungus, the acaricide and the association of both. Firstly, a study was carried out to determine the most appropriate methodology to evaluate the in vitro effect of the fungus M. anisopliae on larvae of R. microplus tick. For this, we compared the Modified Larval Packet Test (LPT) and the Larval Immersion Test (LIT). The values of lethal time (LT50) obtained in the highest concentration of M. anisopliae (108conidia / mL) were 24.8 and 9.2 days for LPT and LIT, respectively. Mortality after 21 days was 38% and 98% for LPT and LIT, respectively, at the same concentration. The LIT proved to be the most indicated test to be used and was therefore chosen to carry out the following experiments Then, a study was performed to compare the susceptibility of different R. microplus isolates to M. anisopliae fungus. Sixty-seven field isolates were evaluated. For this, R. microplus larvae were immersed in a suspension of M. anisopliae (108conidia/mL) for 5 min. Lethal times (LT50) ranged from 2.6 to 24.9 days. Mortality observed on the 15th day after treatment ranged from 26.3 to 100% in the tested samples. These results demonstrated that R. microplus field populations showed a high variation in their susceptibility to M. anisopliae. Finally, a RNAseq analysis of R. microplus larvae exposed to M. anisopliae, cypermethrin, association of both or untreated (control) was performed. Analysis of the transcripts of the four groups generated a total of 507,792 sequences with a total length of 303,160,891 bp. We found 31 differentially expressed genes in the control group when compared to M. anisopliae, 39 with cypermethrin and 73 with M. anisopliae + cypermethrin. M. anisopliae and the association group had 81 differentially expressed genes and M. anisopliae and cypermethrin, 46 There were 177 differentially expressed genes when comparing M. anisopliae + cypermethrin with cypermethrin exposed larvae. The results of this study demonstrated that the association of M. anisopliae + cypermethrin increased the expression of genes related to response to aggression, possibly because the M. anisopliae + cypermethrin association causes a greater aggression to the tick and, then it could respond quickly, leading to overexpression of defense genes. The findings of this study provide information on the pathways and molecular mechanisms of R. microplus in response to the interaction of M. anisopliae and acaricides. In addition, these studies establish the basis for future research on key genes that control the susceptibility of R. microplus to M. anisopliae. The synergism evidenced in our studies confirms the idea that integrated control using biological control and chemical control is an option both for the control of acaricide resistant tick strains and for a faster control of tick strains that do not show resistance or exhibit intermediate resistance.

O carrapato Rhipicephalus microplus é o principal ectoparasita de bovinos. O controle de R. microplus baseia-se principalmente no uso de acaricidas químicos, o que contribuiu para o problema emergente da seleção de populações de carrapatos resistentes. Portanto, há a necessidade do desenvolvimento de métodos mais eficientes/sustentáveis de controle, como o controle biológico utilizando fungos acaropatogênicos. A eficácia do fungo Metarhizium anisopliae de forma isolada ou em associação com acaricida químico para controle do carrapato bovino já foi evidenciada em condições de campo utilizando uma cepa de carrapatos resistente à acaricidas. No entanto, pouco se sabe sobre os mecanismos moleculares de R. microplus envolvidos na sua interação com M. anisopliae e com acaricidas. Assim, o objetivo do presente estudo foi avaliar a resposta de larvas de R. microplus expostas ao fungo, ao acaricida e à associação de ambos. Primeiramente foi realizado um estudo para determinar a metodologia mais indicada para avaliar o efeito in vitro do fungo M. anisopliae sobre larvas de R. microplus. Para isso, comparamos o Teste de Pacote de Larvas modificado (TPL) e o Teste de Imersão de Larvas (TIL). Os valores de tempo letal mediano (TL50) obtido na maior concentração de M. anisopliae (108conídios/mL) foram 24,8 e 9,2 dias para o TPL e TIL, respectivamente. A mortalidade após 21 dias foi de 38% e 98% para o TPL e TIL respectivamente, na mesma concentração. O TIL demonstrou ser o teste mais indicado a ser utilizado, sendo, portanto, escolhido para realização dos experimentos futuros. Em seguida foi realizado um estudo para comparar a suscetibilidade de diferentes isolados de R. microplus ao fungo M. anisopliae. Foram avaliados 67 isolados de campo. Para tanto, as larvas de R. microplus foram imersas em uma suspensão de M. anisopliae (108conídios/mL) durante 5 min. Os tempos letais medianos (TL50) variaram de 2,6 a 24,9 dias A mortalidade observada no 15º dia após o tratamento variou de 26,3 a 100% nas amostras testadas. Esses resultados demonstraram que as populações de campo de R. microplus apresentam uma alta variação em sua suscetibilidade a M. anisopliae. Por fim, foi realizada uma análise transcricional (RNAseq) de larvas de R. microplus expostas a M. anisopliae, cipermetrina, associação de ambos e do controle (não-tratado). A análise dos transcritos dos quatro grupos gerou um total de 507.792 sequências com um tamanho total de 303.160.891 pb. Foram encontrados 31 genes diferencialmente expressos no grupo controle quando comparado com M. anisopliae, 39 com cipermetrina e 73 com M. anisopliae + cipermetrina. M. anisopliae e o grupo da associação apresentaram 81 genes diferencialmente expressos e M. anisopliae e cipermetrina, 46. Houve 177 genes diferencialmente expressos ao comparar M. anisopliae + cipermetrina com larvas expostas à cipermetrina Os resultados deste estudo demonstraram que a associação M. anisopliae + cipermetrina aumentou a expressão de genes relacionados a resposta à agressão, provavelmente pelo fato da associação provocar uma agressão maior ao carrapato e este responder de forma mais rápida, levando à superexpressão de genes de defesa. As descobertas deste estudo fornecem informações sobre as vias e mecanismos moleculares de R. microplus ativados em resposta à interação de M. anisopliae e a acaricida. Além disso, esses estudos estabelecem as bases para pesquisas futuras sobre genes-chave que controlam a suscetibilidade de R. microplus a M. anisopliae. O sinergismo evidenciado em nossos estudos comprova a ideia de que o controle integrado, utilizando o controle biológico com o controle químico é uma opção tanto para o controle de cepas de carrapatos resistentes à acaricidas, quanto para um controle mais rápido de cepas de carrapatos que não apresentam resistência ou que apresentem resistência intermediária. / The tick Rhipicephalus microplus is the major cattle ectoparasite. The control of R. microplus is based mainly on the use of chemical acaricides, which contributed to the emerging problem of the selection of tick populations resistant to acaricides. Therefore, there is a need for the development of more efficient/sustainable methods of control, such as biological control using acari pathogenic fungi. The effectiveness of the fungus Metarhizium anisopliae alone or in association with chemical acaricide to control the bovine tick has already been evidenced under field conditions using an acaricide resistant tick strain. However, to date, little is known about the molecular pathways of R. microplus involved with its interaction with M. anisopliae and with acaricides. Thus, the aim of the present study is to evaluate the response of R. microplus larvae exposed to the fungus, the acaricide and the association of both. Firstly, a study was carried out to determine the most appropriate methodology to evaluate the in vitro effect of the fungus M. anisopliae on larvae of R. microplus tick. For this, we compared the Modified Larval Packet Test (LPT) and the Larval Immersion Test (LIT). The values of lethal time (LT50) obtained in the highest concentration of M. anisopliae (108conidia / mL) were 24.8 and 9.2 days for LPT and LIT, respectively. Mortality after 21 days was 38% and 98% for LPT and LIT, respectively, at the same concentration. The LIT proved to be the most indicated test to be used and was therefore chosen to carry out the following experiments Then, a study was performed to compare the susceptibility of different R. microplus isolates to M. anisopliae fungus. Sixty-seven field isolates were evaluated. For this, R. microplus larvae were immersed in a suspension of M. anisopliae (108conidia/mL) for 5 min. Lethal times (LT50) ranged from 2.6 to 24.9 days. Mortality observed on the 15th day after treatment ranged from 26.3 to 100% in the tested samples. These results demonstrated that R. microplus field populations showed a high variation in their susceptibility to M. anisopliae. Finally, a RNAseq analysis of R. microplus larvae exposed to M. anisopliae, cypermethrin, association of both or untreated (control) was performed. Analysis of the transcripts of the four groups generated a total of 507,792 sequences with a total length of 303,160,891 bp. We found 31 differentially expressed genes in the control group when compared to M. anisopliae, 39 with cypermethrin and 73 with M. anisopliae + cypermethrin. M. anisopliae and the association group had 81 differentially expressed genes and M. anisopliae and cypermethrin, 46 There were 177 differentially expressed genes when comparing M. anisopliae + cypermethrin with cypermethrin exposed larvae. The results of this study demonstrated that the association of M. anisopliae + cypermethrin increased the expression of genes related to response to aggression, possibly because the M. anisopliae + cypermethrin association causes a greater aggression to the tick and, then it could respond quickly, leading to overexpression of defense genes. The findings of this study provide information on the pathways and molecular mechanisms of R. microplus in response to the interaction of M. anisopliae and acaricides. In addition, these studies establish the basis for future research on key genes that control the susceptibility of R. microplus to M. anisopliae. The synergism evidenced in our studies confirms the idea that integrated control using biological control and chemical control is an option both for the control of acaricide resistant tick strains and for a faster control of tick strains that do not show resistance or exhibit intermediate resistance.