Atividade inseticida e repelente de plantas do cerrado no controle alternativo do mosquito Aedes Aegypti

Abstract

The mosquito Aedes aegypti is the central vector of transmission of dengue fever and yellow fever. The majority of the world population lives in countries where the incidence of dengue fever is high, presenting a higher number of cases with death. Essential oils are complex mixtures of low molecular weight volatile organic compounds, some essential oils may still act as synergists, and may provide a reduction in the amount of oil to be applied to control a particular pest, which would reduce the costs of handling and the risks to the environment. The objective of this study was to evaluate the effects of the essential oil isolated from Hypenia irregularis and the synergistic proportions methodology with the combination of the essential oils of Cymbopogon citratus, Hyptis crenata and Morinda citrifolia, against 3rd instar larvae and adult mosquitoes of the vector Ae. aegypti. Larvae and mosquitoes were used to create the Integrated Pest Management Laboratory of the Federal University of Tocantins, Gurupi-TO Campus. The chemical composition of the oil was determined using the Gas Chromatography / Mass Spectrometer (GS / MS) technique. Concentrations ranging from 0.007 to 0.13 μL.mL-1 were applied for all the isolated tests, whereas for the synergism proportions were prepared using 100 μL.mL-1 of the essential oil as base. Thus, the best possible synergistic interaction with all bioassays was 1: 1 using H.irregularis x M. citrifolia. For the larvicidal test LC50 was denoted 0.037 μL.mL-1 and LC95 was 0.112 μL.mL-1 , already using synergy LC50 0.039 and LC95 0.119. In the oviposition bioassay it was observed that the higher the concentration of essential oil used (0.2 μL.mL-1), the lower the number of eggs deposited, the less than 50 eggs for H. irregularis isolated and 20 eggs with the synergism, when compared to untreated tests. Also, the action of H. irregularis oil showed better results with both the isolated essential oil and the interaction of the concentrations of the oils than N, N-diethyl-m-toluamide in 135 minutes of exposure to the females of the mosquitoes.