18 research outputs found

    Ensaios preliminares em laboratório para verificar a ação moluscicida de algumas espécies da flora brasileira

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    The molluscicide activity of sixty-eight extracts from twenty-three Brazilian plants was studied in the laboratory. The solutions, in dechlorinated water, of hexanic and ethylic extracts at 1, 10 and 100 ppm concentrations, were tested on adult snails and egg masses of Biomphalaria glabrata, reared in the laboratory. The plants with molluscicide activity on adult snails and/or egg masses at 100 ppm concentration were: Arthemisia verlotorum Lamotte, Caesalpinia peltophoroides Benth, Cassia rugosa G. Don, Eclipta alba Hassk, Euphorbia pulcherrima Willd, Euphorbia splendens Bojer, Joannesia princeps Vell, Leonorus sibiricus L., Macrosiphonia guaranitica Muell, Nerium oleander L., Palicourea nicotianaefolia Cham. and Schlech., Panicum maximum M., Rumex crispus L., Ruta graveolens L. and Stryphnodendron barbatiman M.Estudou-se em laborat√≥rio a atividade moluscicida de 68 extratos de 23 plantas brasileiras. As solu√ß√Ķes em √°gua desclorada dos extratos hex√Ęnicos e etan√≥lico, nas concentra√ß√Ķes de 1, 10 e 100 ppm, foram testadas sobre caramujos adultos e desovas de Biomphalaria glabrata, criados em laborat√≥rio. As plantas que demonstraram a√ß√£o moluscicida na concentra√ß√£o de 100 ppm foram: Arthemisia verlotorum Lamotte, Caesalpinia peltophoroides Benth, Cassia rugosa G.Don., Eclipta alba Hassk, Euphorbia pulcherrima Willd, Euphorbia splendens Bojer, Joannesia princeps Vell, Leonorus sibiricus L.,Macrosiphonia guaranitica Muell,Nerium oleander L., Palicourea nicotianaefolia Cham, e Schlech., Panicum maximum M., Rumex crispus L., Ruta graveolens L., e Stryphnodendron barbatiman M

    Influence of metallic magnesium and various magnesium salts on egg-masses of Biomphalaria glabrata (Say, 1818)

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    Solutions of magnesium metallic and other salts of magnesium were tested in the laboratory to study the action on B. glabrata oviposition. For each solution, 10 adult snails from Pampulha, Belo Horizonte-MG (Brazil), reared in the laboratory, were used. In experiment I solutions, in dechlorinated water, of magnesium (Mg), magnesium chloride (MgCl2. 6H2O), magnesium carbonate [(MgCO3)4.Mg(OH)2.nH2O], magnesium nitrate [Mg(NO3)2.6H2O] and magnesium sulfate (MgSO4.7H2O) were tested; and in experiment II, solutions of Mg, Mg + latosoil, MgCO3, MgCO3 + latosoil, always at concentrations of 500 and 1000 ppm. The snails were kept in dechlorinate water for an adaptation period of two weeks. Then, in the solutions tested, for an exposure period of four weeks, and then in dechlorinated water for a recuperation period of a further two weeks. Each seven days egg-masses were counted and eliminated and the solutions renewed. It was observed that the solutions of Mg and MgCO3 alone or in association with the latosoil were responsible for a significant decrease in the number of egg-masses, but not a complete stopping of oviposition, when adaptation and exposure periods were compared. The solutions of Mg and MgCO3 must not be considered as possible molluscicide for the control of B. glabrata populations, since the activity was detected only when a high concentration of those substances were used.Solu√ß√Ķes de magn√©sio met√°lico e diferentes sais de magn√©sio foram testadas em laborat√≥rio, a fim de comprovar a a√ß√£o das mesmas sobre a oviposi√ß√£o de B. glabrata. Usaram-se, para cada solu√ß√£o, dez caramujos adultos origin√°rios da Pampulha, Belo Horizonte-MG (Brasil), criados em laborat√≥rio. No experimento I foram estudadas solu√ß√Ķes em √°gua desclorada de magn√©sio elementar (Mg), cloreto de magn√©sio (MgCl2.6H2O), carbonato de magn√©sio [(MgCO3)4.Mg(OH)2.nH2O], nitrato de magn√©sio [Mg(NO3)2. 6H2O] e sulfato de magn√©sio (MgSO4.7H2O), e no experimento II, Mg, Mg + latossolo, MgCO3, MgCO3 + latossolo, sempre nas concentra√ß√Ķes de 500 e 1.000 ppm. Durante duas semanas os planorb√≠deos permaneceram em √°gua para adapta√ß√£o; em seguida, por quatro semanas em exposi√ß√£o com as solu√ß√Ķes testadas e, posteriormente, em √°gua por mais duas semanas para recupera√ß√£o. A cada sete dias as desovas eram contadas, eliminadas e as solu√ß√Ķes renovadas. Foi observado que as solu√ß√Ķes de Mg e MgCO3, isoladamente ou associada ao latossolo, produziram uma diminui√ß√£o significativa do n√ļmero de desovas dos caramujos, mas n√£o parada completa de oviposi√ß√£o, quando comparados os per√≠odos de adapta√ß√£o com os de exposi√ß√£o. As solu√ß√Ķes de Mg e MgCO3 n√£o devem ser consideradas como produtos promissores para o controle da popula√ß√£o de B. glabrata, em virtude da diminui√ß√£o das desovas s√≥ terem sido observadas quando foram utilizadas concentra√ß√Ķes muito altas

    Repovoamento de criadouros de Biomphalaria glabrata após tratamento com niclosamida

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    Experiments were undertaken both in the laboratory and in the field between 1980-1984 to evaluate the causes of repopulation of breeding places of Biomphalaria glabrata following treatment with Niclosamide. Laboratory bioassays showed that the susceptibility to emulsifiable Niclosamide of B. glabrata collected monthly from an irrigation ditch system varied during the year. Lethal concentrations (LC90) ranged between 0.15 mg/l-1 and 0.60 mg/l-1. Statistically significant differences (alpha=0.01) were evident between the months of May/82 and January/83 and December/82 and January/83, and were related to snail nutrition. In the field two types of foci of B. glabrata were treated with 10 ppm of Niclosamide. The first one consisted of a reservoir of 12000 1 of water in which 14.5% of snails were infected with Schistosoma mansoni. One application of molluscicide followed by cleaning of the reservoir eliminated all the snails. The second one consisted of an irrigation system in which 5.6% of the snails were infected with S. mansoni. One application of molluscicide without cleaning the ditches reduced the density of snails by 98%. The causes of the survival of 2.0% of the snails in the ditches are discussed in relation to the substratum of the breeding places and the treatment technique.Experimentos foram feitos no laborat√≥rio e no campo nos anos de 1980 a 1984, objetivando detectar as causas do repovoamento de criadouros de Biomphalaria glabrata ap√≥s tratamento com niclosamida. Os bioensaios no laborat√≥rio mostraram que a suscetibilidade √† niclosamida emulsion√°vel de B. glabrata coletada mensalmente em um sistema de valas de irriga√ß√£o, variou durante o ano. As concentra√ß√Ķes letais CL90 foram 0,15 mgl-1 a 0,60 mgl-1, apresentando diferen√ßas significantes estatisticamente (p < 0,01) nos meses de maio/82 e janeiro/83 e dezcmbro/82 e janciro/83, relacionadas a nutri√ß√£o. No campo, foram tratados dois tipos de focos com solu√ß√£o aquosa a 10 ppm de niclosamida. O primeiro era formado por reservat√≥rio com cerca de 12.000 litros de √°gua e continha 14,5% de moluscos infectados pelo Schistosoma mansoni. Uma √ļnica aplica√ß√£o do produto, seguida de esvaziamento e limpeza do reservat√≥rio, eliminou os moluscos. O segundo, era constitu√≠do por sistema de valas e po√ßo com 5,6% de moluscos infectados por S. mansoni. Uma √ļnica aplica√ß√£o do produto, sem limpeza das valas, reduziu a densidade planorb√≠dica 98%. As causas da sobreviv√™ncia de 2% dos moluscos do sistema de valas, s√£o discutidas, sendo relacionadas ao substrato do criadouro e a t√©cnica utilizada no tratamento

    Evaluation of the molluscicidal properties of Euphorbia splendens var. hislopii (n. e. b.) (Euphorbiaceae) - 1: experimental test in a lentic habitat

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    The latex of Euphorbia splendens var. hislopii, at concentrations between 5 to 12 mg/l, kills 100% of the population of Biomphalaria glabrata in a lentic habitat, after 24 h. The lyophilized latex, stocked for 18 months, killed only 34.2% of the snails, at the concentration of 5 mg/l, and 96.0% at 12 mg/l. No lethal effect was observed among Pomacea haustrum exposed to the same concentrations of the molluscicide

    Ensaios preliminares do Guaiacum officinale L. como moluscicida

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    Suspens√Ķes aquosas do pericarpo do fruto, da casca da raiz, das folhas e das sementes de Guaiacum officinale foram testadas como moluscicida, cercaricida e piscicida em diferentes concentra√ß√Ķes. Em laborat√≥rio, a suspens√£o do pericarpo do fruto apresentou 100% de mortalidade a 100 ppm para desovas de B. glabrata, a 20 ppm para caramujos adultos de Biomphalaria glabrata, B. straminea e B. tenagophila, a 5 ppm para Lebistes reticulatus (peixes) e a 1 ppm para cerc√°rias de Schistosoma mansoni. O extrato etan√≥lico do pericarpo do fruto n√£o foi ativo para caramujo adulto de B. glabrata. As doses letais para 90% dos caramujos adultos (DL90), ap√≥s 24 horas de exposi√ß√£o, usando a suspens√£o do pericarpo do fruto foram de: 15 ppm para B. glabrata; 14 ppm para B. straminea e 18 ppm para B. tenagophila. As DL90 das suspens√Ķes das casca da raiz, sementes e folhas contra B. glabrata foram de 57, 33 e 15 ppm, respectivamente. No campo, coma suspens√£o do pericarpo do fruto a mortalidade de caramujos adultos de B. glabrata foi de 68% a 20 ppm e 100% a 40 ppmAqueous suspensions of fruit's pericarp, leaves, root's bark and seeds of Guaiacum officinale were tested at different concentrations as molluscicide, cercaricide and piscicide. In the laboratory the suspension of fruit's pericarp produced 100% mortality for egg masses of B. glabrata at 100 ppm, for adult snails of Biomphalaria glabrata, B. straminea and B. tenagophila at 20 ppm, for Lebistes reticulatus (fishes) at 5 ppm and Schistosoma mansoni's cercariae at 1 ppm. The ethanolic extract of fruit's pericarp was not active against adult snails of B. glabrata. The letal dose for adult snails(DL90) of the aqueous suspension of fruit's pericarp after 24 hours exposure, were: 15 ppm for B. glabrata; 14 ppm for B. straminea and 18 ppm for B. tenagophila. The DL90 of aqueous suspensions of root's bark, seeds and leaves were 57 ppm, 33 ppm and 15 ppm, respectively. In the field, B. glabrata adult snail mortality was 68% at 20 ppm and 100% at 40 ppm, when using suspension of fruit's pericar
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