Larvicidal activity of vegetable oils against Aedes aegypti larvae

Aedes aegypti L. is the mosquito vector of yellow fever, dengue, zika, and chikungunya viruses. The prevention and control of such diseases usually rely on the use of chemicals, that can cause harm to human health and the environment. Vegetable oils with larvicidal activity are used as an alternative tool to control this insect. This study aimed to evaluate the larvicidal activity of vegetable oils from Caryocar coriaceum, Mauritia fIexuosa, Carapa guianensis, Copaifera langsdorffii, Ricinus communis and Cocos nucifera against A. aegypti larvae. The experiment was divided into two bioassays. In the first, a completely randomized design was used with seven treatments (six vegetable oils at 500 ppm and one control with four replications). The number of dead larvae was evaluated 24, 48, 72, 96, and 120 h after exposure. In the second bioassay, the most efficient vegetable oils from the first bioassay (C. coriaceum and M. flexuosa) were used at the concentrations of 0, 500, 1000, 1500, 2000, and 2500 ppm, with four replications. The number of dead larvae was evaluated according to the first bioassay. All oils used had larvicidal activity on third instar stage larvae of A. aegypti, with greater efficiency 120 h after exposure. The oils of C. coriaceum and M. flexuosa at 2500 ppm had the best efficacy in the larvae control. The LD10, LD50, and LD90 of M. flexuosa oil recommended for controlling larvae are 234, 648, and 1794 ppm, respectively.