First report on susceptibility of wild Aedes aegypti (Diptera: Culicidae) using Carapa guianensis (Meliaceae) and Copaifera sp (Leguminosae)

Oils of Carapa guianensis and Copaifera spp. are well known in the Amazonian region as natural insect repellent, and studies have reported their efficiency as larvicide against some laboratory mosquito species. However, in wild populations of mosquitoes, these oils have not yet been evaluated. Thus, the objective of this study was to investigate their efficiency as larvicide in wild populations of Aedes aegypti with a history of exposure to organophosphate. The susceptibility of larvae was determined under three different temperatures, 15A degrees C, 20A degrees C, and 30A degrees C. For each test, 1,000 larvae were used (late third instar and early fourth instar-four replicates of 25 larvae per concentration). Statistical tests were used to identify significant differences. The results demonstrated that as the laboratory A. aegypti, the wild populations of A. aegypti were also susceptible to C. guianensis and Copaifera sp. oils. The lethal concentrations for Copaifera sp. ranged from LC50 47 to LC90 91 (milligrams per liter), and for C. guianensis, they were LC50 136 to LC90 551 (milligrams per liter). In relation to different temperature, the effectiveness of the oils on larvae mortality was directly related to the increase of temperature, and better results were observed for temperature at 25A degrees C. The results presented here indicate the potential larvicidal activity of C. guianensis and species of Copaifera, in populations of A. aegypti from the wild. Therefore, the results presented here are very important since such populations are primarily responsible for transmitting the dengue virus in the environment.