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Previous issue date: 2016-10-03 / CAPES / CNPq / The tick Rhipicephalus microplus has been considered the most important parasite in cattles. It causes economic lost in dairy and beef cattle. As the fungus Metarhizium spp, a promising biocontrol agent, with remarkable virulence and efficacy against this arthropod. Environmental conditions can directly influence entomopathogenic fungal activity when it is released on the field. Therefore, adjuvants should be used to enhance fungal pathogenicity, stability and viability under unfavorable environmental conditions. Accordingly, several oily vehicles have been studied as adjuvant components. The present study aimed at investigate under semi-natural conditions, the permanence of fungi in the soil, the pathogenicity and the efficacy of two isolates of Metarhizium anisopliae sensu latu (ARSEF 3641 and CG 148) formulated in oil (soy and mineral), on engorged females of R. microplus engorged. The fungus was mass produced on rice cultivation and the semi-natural environment was framed from pots with Brachiaria brizantha cv. Marandu. The experiment was compound of seven groups: Control OLV (treated with vegetable oil and 0,1% of tween 80), Control OLM (treated with mineral oil and 0,1% of Tween 80), Treated 3641 OLV (treated with isolated ARSEF 3641 + vegetable oil); Treated 3641 OLM (treated with ARSEF 3641 isolated + mineral oil); Treated CG 148 OLV (treated with CG148 isolated + vegetable oil); Treated CG 148 OLM (treated with CG 148 isolated + mineral oil). Each group contained ten pots. The soil of each pot was sprayed with 80 ml of formulation at 108 conidia/ml in accordance with the proposed group. Afterwards, 5 engorged females were put on each pot. All pots were daily inspected for evaluating the percent mortality of famales. The efficacy of formulations tested was obtained by comparison of the number of live larvae collected at the apex of forage leaves of the control groups with the number of larvae from the treated groups. The collection of larvae was held on the 7th, 14th and 21st after the hatch. To evaluate the presence of Metarhizium spp. in the soil, a methodology was established to quantify the colonies number found in samples collected from each pot before the spraying and at 3th, 7th, 21th and 60th day after treatment. For the standardization of the methodology set out in the quantification of colonies in the soil, data from three evaluators were confronted by Kaapa test, the statistical analysis of data were submitted to the distribution of normality by the Shapiro-Wilk test. Data were analyzed as nonparametric and we used the Kruskal-Wallis test for analysis of variance followed by the Student-Newman-Keuls to compare the mean. The tested oil fungal formulations showed daily efficacy ranging between 85,08 and 96,13% compared to their respective controls. The group trated with isolated ARSEF 3641 formulated both in mineral oil and vegetable oil showed the better efficacy when compared to the respective control groups. Also, during tick females? laying period, it was possible to observe Metarhizium spp. externalization on R. microplus engorged females cuticle in all groups that were exposed to fungal formulations, confirming the ability of these fungal isolates on develop all growth stages over this arthropod in semi-natural conditions. Both fungal isolates formulated in vegetable or mineral oil showed to be able to remain active in semi-natural environment as they were pathogenic and effective against engorged females, and able to reduce significantly future generations of the tick. / O carrapato Rhipicephalus microplus ? considerado um dos principais agentes de parasitismo em bovinos por representar significativas perdas econ?micas na pecu?ria de leite e corte. Sendo o fungo Metarhizium spp, um promissor agente biocontrolador para este artr?pode, por apresentar grande virul?ncia e efic?cia contra este ectoparasita. Agentes microbianos quando lan?ados a campo, podem sofrer grande influ?ncia pelas intemp?ries ambientais, devendo estes receberem componentes que favore?am a sua patogenicidade, perman?ncia e viabilidade no ambiente, a fim de atingirem resultados satisfat?rios. Visto isto, diferentes ve?culos oleosos v?m sendo alvos de estudos como componentes adjuvantes. O objetivo deste trabalho foi investigar, sob condi??es seminaturais, a perman?ncia no solo, a virul?ncia e a efic?cia de dois isolados do fungo Metarhizium anisopliae s.l. (ARSEF 3641 e CG 148) formulados em ?leo (soja e mineral) sobre f?meas de R. microplus, assim como a taxa e recupera??o de larvas. O fungo foi produzido em massa a partir do cultivo dos isolados em arroz e para a forma??o do ambiente seminatural, sementes de Brachiaria brizantha, cultivar Marandu, foram plantadas em vasos de polipropileno. O experimento foi composto por sete grupos: Controle CTR (grupo sem tratamento); Controle OLV (tratado com ?leo vegetal e Tween 80 a 0,1%), Controle OLM (tratado com ?leo mineral e Tween 80 a 0,1%), Tratado 3641 OLV (tratado com o isolado ARSEF 3641 + ?leo vegetal + Tween 80 a 0,1%); Tratado 3641 OLM (tratado com o isolado f?ngico ARSEF 3641 + ?leo mineral + Tween 80 a 0,1%); Tratado CG 148 OLV (tratado com o isolado 148 + ?leo vegetal + Tween 80 a 0,1%); Tratado CG 148 OLM (tratado com o isolado CG 148 + ?leo mineral + Tween 80 a 0,1%). Cada grupo conteve dez vasos. Foram pulverizados sobre a superf?cie do solo de cada vaso, 80ml da formula??o a 108 con?dios/ml de acordo com o grupo proposto para cada formula??o e posteriormente 5 f?meas ingurgitadas de peso m?dio e homog?neo foram adicionadas em cada vaso. Os mesmos foram vistoriados diariamente para a avalia??o da mortalidade das f?meas. O percentual de efic?cia das formula??es dos isolados testados foi obtido a partir da compara??o entre o n?mero de larvas vivas coletadas no ?pice das folhas da forrageira dos grupos controles e dos grupos tratados. A coleta de larvas foi realizada no 7?, 14? e 21? ap?s a eclos?o das mesmas. Para a avalia??o da presen?a de Metarhizium spp. no solo, foi estabelecido e validada uma metodologia para a quantifica??o do n?mero de col?nias encontradas em amostras coletadas de cada vaso antes da pulveriza??o e no 3?, 7?, 21? e 60? dia ap?s o tratamento. A valida??o do m?todo se fez pelo confronto da avalia??o de tr?s observadores utilizando o teste Kaapa. Para a an?lise estat?stica dos demais dados, os mesmos foram submetidos ? distribui??o da normalidade pelo teste de Shapiro-Wilk sendo classificados como n?o param?tricos e foi utilizado o teste de Kruskal Wallis para an?lise de vari?ncia, seguido do Student-Newman-Keuls para compara??o entre as ordena??es m?dias. Os grupos tratados com as formula??es f?ngicas oleosas apresentaram efic?cia m?dia no controle de R. microplus variando entre 85,08 e 96,13% em rela??o aos seus respectivos grupos controles durante o per?odo de avalia??o do n?mero de larvas infestantes. O isolado ARSEF 3641 formulado tanto em ?leo vegetal quanto em ?leo mineral apresentou os melhores percentuais de efic?cia. Durante o per?odo de postura das f?meas, foi poss?vel encontrar a exterioriza??o de Metarhizium sp. nas mesmas em todos os grupos tratados com as formula??es f?ngicas, confirmando a capacidade dos isolados f?ngicos em se manterem e realizarem todas as fases de desenvolvimento sobre o artr?pode em condi??es seminaturais. Ambos os isolados testados, nas duas condi??es de formula??es propostas, mostraram-se aptos a permanecerem ativos no ambiente seminatural, virulentos e eficazes contra f?meas de R. microplus, sendo capazes de reduzir significativamente gera??es futuras do carrapato.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:jspui/2389 |
| Date | 03 October 2016 |
| Creators | MARCIANO, Allan Felipe |
| Contributors | Bittencourt, V?nia Rita Elias Pinheiro, Perinotto, Wendell Marcelo de Souza, Bittencourt, V?nia Rita Elias Pinheiro, Fernandes, Everton Kort Kamp, Angelo, Isabele Costa |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Programa de P?s-Gradua??o em Ci?ncias Veterin?rias, UFRRJ, Brasil, Instituto de Veterin?ria |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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