Atividade larvicida de extratos vegetais de espécies do cerrado sobre Aedes aegypti L. (Diptera: Culicidae)

Abstract

The mosquito species Aedes aegyptiis one of the main vectors arboviruses, including Dengue, Chikungunya and Zika. Its adaptation to urban environments in tropical and subtropical regions exposes 2.5 million people to risks. This vector control, through the use of synthetic insecticides, is an important strategy for these vector-borne diseases control. In this context, natural insecticides are an alternative to synthetics one, since they degrade easily, are less harmful to the environment and less toxic to non-target insects. In thiswork, the larvicidal activity of extracts from Cerrado species against the Aedes aegyptimosquito was evaluated. For that, larvae were exposed to solutions, in different concentrations, according to the WHO protocol, to assess their toxicities. Mortality was verified after 24 and 48 hours of exposure, the results were statistically analyzed and mortality rates were determined. The extracts obtained from the leaves of Philodendron adamantinum, Xylopia emarginata and Schinopsis brasiliensis and from the stembark of Psidium cattleianumand Myracrodruon urundeuva, at a preliminary concentration of 2000 mg/L and both exposure times, showed low (> 30%) or none larvicide activities. Only Magonia pubescens leaf extract showed a mortality rate greater than 90% at 2000 mg/Land 48 hours exposure. However, only at the concentration of 500 mg/L and 48h exposure, statistically significant larvicidal activity was observed, when compared to the positive control, but less than 15%. The results of this study do not rule out, definitively, the species evaluated to have larvicidal activity, as only hydroalcoholic extracts from a single part of each plant were tested.