ABSTRACT
Following the positive results obtained regarding the molluscicidal properties of the latex of Euphorbia splendens that were corroborated in laboratory and field tests restrited conditions, a field study was conducted in experimental streams located in an endemic area. After recording the average annual fluctuation of vectors in three streams, a solution of E. splendens latex at ppm was applied in stream A, a solution of niclosamide at 3 ppm that applied in stream B and a third stream (C) remained untreated for negative control. Applications of E. splendens and niclosamide resulted in a mortality of 100 per cent among the snails collected in the streams A and B. No dead snails were found in the negative control stream. A monthly follow-up survey conducted during three consecutive months confirmed the return of vectors to both experimental streams treated with latex and niclosamide. This fact has called for a need to repeat application in order to reach the snails that remained buried in the mud substrate or escaped to the water edge, as well as, newly hatched snails that did not respond to the concentration of these molluscicides. Adults snails collected a month following treatment led us to believe that they had migrate from untreated areas of the streams to those previously treated.
Subject(s)
Animals , Latex/toxicity , Molluscacides/administration & dosage , Mollusca/drug effects , Biomphalaria/drug effects , Niclosamide/administration & dosage , Schistosomiasis/prevention & control , Snails/drug effectsABSTRACT
Ethanol extracts of 83 plants species belonging to the Asteraceae (Compositae) family, collectes 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 LC90 of 1.5 mg/l and LC50 of 1.0 mg/l. This plant been the object of several studies by other groups and its active components have already been identified as thiophene derivates, 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 per cent of the larvae only at the higher dose tested (100 mg/l)
Subject(s)
Animals , Aedes/drug effects , Plant Extracts/pharmacology , Insecticides/pharmacologyABSTRACT
Extratos brutos, etanólicos, hexânicos, liofilizados de diversos vegetais e ácido anacárdico foram testados quanto a sua influência sobre o comportamento de oviposiçäo das fêmeas de Aedes fluviatilis (Lutz), nas concentraçöes de 100, 10 e 1 ppm. Os estratos de Allium sativum, jatropha curcas. MiKania schenkii, Poinciana regia s Spatodea campanulata mostraram-se repelentes (alfa = 0,05) para as fêmeas na concentraçäo de 100 ppm e os de Anacardium occidentale, Bidens segetum e Caesalpinia peltophoroides também na de 10 ppm. Os extratos Coriandrum stivum (100, 10 e 1 ppm), chara zeylanica (10 ppm), Cupressus sempervirens (10 ppm), Foeniculum vulgare (10 ppm) e Spatodea campanulata (1 ppm) atrairam a oviposiçäo das fêmeas; 13 (52,0%) dos extratos testados foram indiferentes as fêmeas nas concentraçöes utilizadas
Subject(s)
Animals , Aedes , Behavior, Animal/drug effects , Oviposition , Plant ExtractsABSTRACT
As propriedades larvicidas de 34 extratos, provenientes de 29 vegetais, foram testados em larvas de Aedes fluviatilis (Lutz) (Diptera: Culicidae) nas concentraçöes de 100, 10 e 1 ppm. 26,5% dos exames utilizados, reduziram significamente a sobrevida larvária (alfa = 0,05), quando empregados na concentraçäo de 100 ppm (Anacardium occidentale, Agave americana, Allium sativum, Coriandrum sativum, Nerium oleander, Spatodea campanulata, Tibouchina scrobiculata e Vernonia salzmanni). O ácido anacárdio (A. occidentale) mostrou-se larvicida na concentraçäo de 10 ppm e o extrato bruto de A. sativum foi eficaz contra as larvas na concentraçäo de 1 ppm