Larvicide activity of Larrea cuneifolia (Zygophyllaceae) on Aedes aegypti (Diptera: Culicidae).

BATALLÁN G; DOUTHAT B; FLORES FS; TONN C; KONIGHEIM B; CONTIGIANI M; ALMIRÓN W

Buenos Aires

Congreso; ARGENTINE SOCIETY OF BIOLOGY; 2009

Aedes aegypti is the main vector of virus Dengue with a wide distribution in Argentina. Due to the re emergence of this virus in our region, is necessary to find out new strategies of vector?s control. Previous studies have demonstrated insecticide properties of Larrea cuneifolia and L. divaricata on Culex quinquefasciatus, therefore the larvicide activity of L. cuneifolia on Ae. aegypti was evaluated. Three concentrations of extracts of different polarities obtained with chloroform, methanol and hot water were tested (250, 100 and 50 ppm). The extracts were applied in trays containing 30 III stadium larvae; larvae mortality was registered every 24 h. In order to detect differences between the treatments an ANOVA was performed. LC50 and LC90 values were estimated by Probit regression. The chloroformic extract showed the biggest larvicide activity causing 100, 82 and 31% of mortality at 250, 100 and 50 ppm respectively. DL50 and DL90 estimated for this extract were 69 and 110 ppm respectively. Methanolic and hot aqueous extracts caused low mortalities (