Utilização de Bacillus sphaericus Neide, 1904 para controle de Culex quinquefasciatus

Observou-se neste trabalho a resposta de larvas de terceiro estádio de C. quinquefasciatus à uma formulação experimental de B. sphaericus cepa 2362. A tecnologia para obtenção do larvicida obedeceu às etapas de preparação do inoculo, fermentação envolvendo um subproduto industrial (soro de queijo), e formulação líquida com agente dispersante. Com uma mortalidade nula nos controles com água ou com placebo produzido com os agentes formulantes, observou-se como resultados em duas séries uma CL50 de 0,0007323 ± 0,0001 e CL90 de 0,0042320 ± 0,0001 ppm numa delas e CL50 de 0,0006399 ± 0,0001 e CL90 de 0,0066370 ± 0,0001 ppm na outra, considerando-se 10% de creme sedimentado utilizado nas formulações. Conclui-se que 0,01 ppm de formulações experimentais consideradas integralmente seria uma concentração eficaz num meio aquático semelhante ao testado, o que é estimulante para um incremento da produção e a continuidade dos testes com este agente de controle.Baccilus sphaericus NEIDE, 1904 IN THE CONTROL OF Culex quinquefasciatus. The susceptibility of third-instar Culex quinquefasciatus say larvae to Bacillus sphaericus strain 2362 experimentally produced was observed. The larvicide was obtained following fermentation in cheese serum, a by-product of this industrial pro-duction, and formulation as an aquous suspension using surfactant agents. The control mortality either in a non-active formulation or in distilled water was negligible. The lethal concentrations derived from probit analysis were CL50 of 0,0007323 ± 0,0001 and CL90 of 0,0042320 ± 0,0001 ppm in one series and CL50 of 0,0006399 ± 0,0001 and CL90 of 0,0066370 ± 0,0001 ppm in the other one, considering only the 10% of creamy sediment used for formulation. It is proposed that 0,01 ppm of similar formulations considered as a wholecould be used for an effective mortality in similar water conditions, what is promising for an enhanced production of the larvicide and future field scale trials

Utilização de Bacillus sphaericus Neide, 1904 para controle de Culex quinquefasciatus

Observou-se neste trabalho a resposta de larvas de terceiro estádio de C. quinquefasciatus à uma formulação experimental de B. sphaericus cepa 2362. A tecnologia para obtenção do larvicida obedeceu às etapas de preparação do inoculo, fermentação envolvendo um subproduto industrial (soro de queijo), e formulação líquida com agente dispersante. Com uma mortalidade nula nos controles com água ou com placebo produzido com os agentes formulantes, observou-se como resultados em duas séries uma CL50 de 0,0007323 ± 0,0001 e CL90 de 0,0042320 ± 0,0001 ppm numa delas e CL50 de 0,0006399 ± 0,0001 e CL90 de 0,0066370 ± 0,0001 ppm na outra, considerando-se 10% de creme sedimentado utilizado nas formulações. Conclui-se que 0,01 ppm de formulações experimentais consideradas integralmente seria uma concentração eficaz num meio aquático semelhante ao testado, o que é estimulante para um incremento da produção e a continuidade dos testes com este agente de controle.Baccilus sphaericus NEIDE, 1904 IN THE CONTROL OF Culex quinquefasciatus. The susceptibility of third-instar Culex quinquefasciatus say larvae to Bacillus sphaericus strain 2362 experimentally produced was observed. The larvicide was obtained following fermentation in cheese serum, a by-product of this industrial pro-duction, and formulation as an aquous suspension using surfactant agents. The control mortality either in a non-active formulation or in distilled water was negligible. The lethal concentrations derived from probit analysis were CL50 of 0,0007323 ± 0,0001 and CL90 of 0,0042320 ± 0,0001 ppm in one series and CL50 of 0,0006399 ± 0,0001 and CL90 of 0,0066370 ± 0,0001 ppm in the other one, considering only the 10% of creamy sediment used for formulation. It is proposed that 0,01 ppm of similar formulations considered as a wholecould be used for an effective mortality in similar water conditions, what is promising for an enhanced production of the larvicide and future field scale trials

Evaluation of natural foci of Panstrongylus megistus in a forest fragment in Porto Alegre, State of Rio Grande do Sul, Brazil.

Introduction: Panstrongylus megistus is commonly found in wild environments of the State of Rio Grande do Sul, Brazil. The aim of this study was to characterize the network of refuges used by triatomine in a forest fragment of Porto Alegre and to identify Trypanosoma cruzi infection, associated hosts and the epidemiological importance of both hosts and triatomines. Methods: Techniques including the spool-and-line method and active searching (transects) were used to identify natural foci. Results: The food source for each triatomine was determined using the precipitin test, and the infection of marsupials was determined by xenodiagnosis. A total of 33 adults (domestic environment) and 27 nymphs (wild environment) of P. megistus were found in addition to 43 Didelphis albiventris specimens. The infection rates of triatomine adults, triatomine nymphs and opossums with T. cruzi I were 64%, 73% and 69%, respectively. Birds, rodents and opossums were the main resources used by triatomine. Conclusions: This work presents the fi rst characterization of a natural focus of P. megistus in Rio Grande do Sul. The natural characteristics of this focus and its implication in the transmission of T. cruzi are discussed