Repellent and Insecticidal Efficacy of Four Water-Soluble Formulations of Essential Oils Against <i>Aedes aegypti</i>.

Abstract

<h4>Introduction</h4>Arboviral diseases transmitted by the <i>Aedes aegypti</i> mosquito cause high morbidity and mortality worldwide.<h4>Objective</h4>To evaluate the repellent and insecticidal efficacy of water-soluble formulations of essential oils impregnated into mosquito nets against the adult stage of <i>A. aegypti</i>.<h4>Methodology</h4>A randomized laboratory bioassay was conducted using a controlled factorial design to evaluate four essential oil formulations (<i>Eucalyptus globulus, Cymbopogon citratus, Origanum vulgare, and Mentha piperita</i>) at concentrations of 10, 100, and 250 mg/mL. Each experimental group consisted of 60 laboratory-reared adult female <i>A. aegypti</i> specimens. The repellent effect, protection time, and insecticidal effect were evaluated by exposing the insects to a sedated animal bait (<i>Rattus norvegicus albinus</i>) covered with a mosquito net impregnated with the formulations of essential oils and DEET, as a positive control.<h4>Results</h4>The highest efficacy was seen in <i>C. citratus, E. globulus</i>, and <i>O. vulgare</i> at 250 mg/mL, with 93.3%-100.0% repellent effect and 180 min of protection time, similar to that obtained by 100 mg/mL DEET. The highest insecticidal effect was observed in <i>C. citratus</i> (26.7%) at a concentration of 250 mg/mL, similar to that observed in 100 mg/mL DEET. The repellent effect and protection time varied for each concentration tested, except for the insecticide, in which concentrations of 10 and 100 mg/mL had a similar effect (0%-6%).<h4>Conclusions</h4>The repellency of water-soluble formulations of essential oils of <i>C. citratus</i>, <i>E. globulus</i>, and <i>O. vulgare</i> at 250 mg/mL, compared to 100 mg/mL DEET, represents a possible and complementary alternative for mosquito control.