ABSTRACT
Ethanol extracts of 83 plants species belonging to the Asteraceae (Compositae) family, collected in the State of Minas Gerais, Brazil, were tested for larvicidal activity against the mosquito Aedes fluviatilis--Diptera: Culicidae). The extract from Tagetes minuta was the most active with a LC90 of 1.5 mg/l and LC50 of 1.0 mg/l. This plant has been the object of several studies by other groups and its active components have already been identified as thiophene derivatives, a class of compounds present in many Asteraceae species. The extract of Eclipta paniculata was also significantly active, with a LC90 of 17.2 mg/l and LC50 of 3.3 mg/l and no previous studies on its larvicidal activity or chemical composition could be found in the literature. Extracts of Achryrocline satureoides, Gnaphalium spicatum, Senecio brasiliensis, Trixis vauthieri, Tagetes patula and Vernonia ammophila were less active, killing more than 50% of the larvae only at the higher dose tested (100 mg/l).
Subject(s)
Aedes/drug effects , Larva/drug effects , Mosquito Control/methods , Plant Extracts/pharmacology , AnimalsABSTRACT
The influence of environmental and biological factors on the efficacy of Bacillus thuringiensis serovar israelensis and B. sphaericus as mosquito larvicides are reviewed. The importance of strain dependence, cultivating media/methods, mosquito species/specificity, formulations and their relation to mosquito feeding habits, as well as temperature, solar exposure, larval density and concomitant presence of other aquatic organisms are addressed with reference to the present status of knowledge in Brazil.
Subject(s)
Animals , Bacillus thuringiensis , Culicidae , Mosquito Control , BrazilABSTRACT
The influence of environmental and biological factors on the efficacy of Bacillus thuringiensis serovar israelensis and B. sphaericus as mosquito larvicides are reviewed. The importance of strain dependence, cultivating media/methods, mosquito species/specificity, formulations and their relation to mosquito feeding habits, as well as temperature, solar exposure, larval density and concomitant presence of other aquatic organisms are addressed with reference to the present status of knowledge in Brazil.
Subject(s)
Bacillus thuringiensis/physiology , Culicidae/microbiology , Mosquito Control/methods , Animals , BrazilABSTRACT
Two fish species, Astronotus ocellatus (Cichlidae) and Macropodus opercularis (Anabatidae) were tested for predacious behavior toward immature mosquitoes (Aedes fluviatilis, Diptera:Culicidae) and schistosomiasis snail hosts (Biomphalaria glabrata, Mollusca:Planorbidae), in the presence or absence of non-living food and in laboratory conditions. A. ocellatus, a species indigenous to Brazil, was a very efficient predator of both organisms (alpha = 0.05); M. opercularis, an exotic species, preyed well on immature mosquitoes, but small snails and snail egg-masses were ingested only irregularly. Both fish species seemed to prefer live to non-living food.
Subject(s)
Aedes , Biomphalaria , Fishes , Pest Control, Biological/methods , Animals , Mosquito Control/methodsABSTRACT
The larvicidal properties of 34 plant extracts were tested against Aedes fluviatilis (Lutz) (Diptera: Culicidae) larvae, at 100, 10 and 1 ppm concentrations; 26.6% of the extracts enhanced larval mortality (alpha = 0.05) at 100 ppm (Anacardium occidentale, Agave americana, Allium sativum, Coriandrum sativum, Nerium oleander, Spatodea campanulata, Tibouchina scrobiculata and Vernonia salzmanni). Anacardic acid (A. occidentale) was effective at 10 ppm and A. sativum (crude extract) at 1 ppm.
Subject(s)
Aedes , Insecticides , Plant Extracts , AnimalsSubject(s)
Biomphalaria , Leeches , Pest Control, Biological , Animals , Biomphalaria/physiology , Female , OvipositionABSTRACT
O potencial de predacao de Helobdella triserialis lineata sobre desovas e exemplares de Biomphalaria straminea e Biomphalaria tenagophila foi estudado em laboratorio visando, por um lado, verificar a influencia desta predacao sobre criacoes destes moluscos em laboratorio e, por outro, avaliar a possivel utilizacao deste hirudineo no controle de populacoes de planorbineos hospedeiros intermediarios da esquistossomose mansoni em condicoes naturais. Nas condicoes experimentais exemplares recem-eclodidos,jovens e adultos de B.straminea e B. tenagophila, foram predados por H: t. lienata que nao predou as desovas dos planorbineos. Observou-se uma ligeira aceleracao no crescimento e uma discreta reducao na oviposicao dos planorbineos mantidos juntos com os hirudineos
Subject(s)
Animals , Biomphalaria , Leeches , Pest Control, BiologicalSubject(s)
Aedes , Culex , Leeches/physiology , Pest Control, Biological , Aedes/growth & development , Animals , Culex/growth & development , Female , OvipositionABSTRACT
Foi avaliada a atividade predatoria, em laboratorio, de Helobdella triserialis lineata (Hirudinea: Glossiphonidae) sobre ovos, larvas e pupas de Aedes fluviatilis e Culex quinquefasciatus (Diptera: Culicidae), bem como a influencia da presenca desses hirudineos sobre o comportamento de oviposicao das femeas das duas especies de mosquitos. Experimentos adicionais foram feitos testando a influencia da profundidade da agua e da sua salinidade sobre a capacidade predatoria dos hirudineos. Nas condicoes do experimento, foi observada predacao de larvas e pupas, porem nao de ovos das duas especies de dipteros. Numero estatisticamente menor de desovas foi depositado por femeas de Cx. quinquefasciatus em recipientes que continham hirudineos, nao ocorrendo o mesmo com femeas de Ae. fluviatilis. As diferentes profundidades de agua testadas nao interferiram na atividade predatoria de H. t. lineata e somente em concentracoes acima de 3% de NaC1 essa atividade mostrou-se bastante diminuida
Subject(s)
Female , Animals , Aedes , Culex , Leeches , Pest Control, BiologicalABSTRACT
A predacao de Helobdella triserialis lineata Blanchard, 1849 sobre desovas e exemplares de Biomphalaria glabrata Say, 1818, foi acompanhada visando por um lado verificar a extensao desta predacao sobre criacoes deste molusco em laboratorio e, por outro, avaliar a possivel utilizacao desta sanguessuga no controle biologico de planorbineos hospedeiros intermediarios da esquistossomose mansoni em condicoes naturais. Nas condicoes do experimento, H. t.lineata mostrou-se eficaz predadora de exemplares de B. glabrata recem-eclodidos, jovens e adultos com diametro de ate 10 mm Nao ocorreu predacao sobre desovas. Observou-se uma aceleracao do crescimento e uma reducao na oviposicao dos planorbineos mantidos juntos com os hirudineos.Foram feitas algumas observacoes sobre a biologia de H. t. lineata e sugeridas medidas de controle deste hirudineo em criacoes de planorbineos de laboratorio
Subject(s)
Animals , Biomphalaria , Pest Control, Biological , LeechesSubject(s)
Aedes/physiology , Animals , Feeding Behavior , Female , Fertility , Oviposition , ReproductionSubject(s)
Aedes/physiology , Diet , Glucose/metabolism , Sucrose/metabolism , Animals , Energy Metabolism , Female , Guinea Pigs , Humans , Longevity , Male , Mice , RatsABSTRACT
Adultos de Aedes fluviatilis foram submetidos em laboratorio a 17 dietas experimentais, constituidas de solucoes de carbohidratos, sangue e agua destilada. Os carbohidratos foram D. Galactose, D. Frutose, D. Manose, D. Xilose , L. Arabinose, Maltose, Sarcarose e Rafinose; os hospedeiros para o repasto sanguineo das femeas em alguns experimentos foram homem, camundongo (Mus musculos), rato (Rattus novergicus) e cobaio (Cavia porcellus).Foi concluido que na concentracao de 5% todos os carbohidratos testados, exceto D. Xilose e L. Arabinose prolongaram consideravelmente a sobrevida de machos e femeas. A eficacia para prolongar a sobrevida media da maioria dos carbohidratos diferiu entre machos e femeas. O aumento da concentracao de alguns carbohidratos para 10% nao foi seguida de um acrescimo na sobrevida media dos mosquitos. Um unico repasto em sangue humano, de rato ou de cobaio, adicional a alimentacao continua com Dextrose prolongou a sobrevida media das femeas