Larvicidal activity of Azadirachta indica, Melaleuca alternifolia, and Carapa guianensis oil compounds and Carica papaya fermented extract on Aedes aegypti

Abstract

The aim of this study was to evaluate the structural changes of Aedes aegypti larvae submitted to treatment with a product based on Azadirachta indica, Melaleuca alternifolia, Carapa guianensis oils and Carica papaya fermented extract. The larvae were exposed for 24h to the experimental groups: product formulated in concentrations of 50% (G1), 25% (G2), and 12.5% (G3); and negative control groups based on water (CN1) and dimethyl sulfoxide (CN2). By the end of the experimental period, some larvae were fixed in 4% buffered glutaraldehyde solution to be processed for optical microscopy. Larvae exposed to G2 and G3 presented more structural damage of the mesentery, Malpighi tubules and nerve ganglia. We conclude that the product formulated in 12.5% and 25% concentrations can be used in the population control of the 3rd larvae stage of Aedes aegypti by causing lethal injuries and avoiding the larvae development.