Potential of garlic oil as a biopesticide against all Aedes aegypti life stages

Vector control remains the most effective approach to prevent dengue, chikungunya and Zika arboviruses transmission. Conventional insecticides have historically failed to control the Aedes aegypti mosquito due to acquired resistance, environmental impact and toxicity. This study evaluated the potential of garlic oil as a biopesticide against the eggs, larvae, pupae and adult forms of Ae. aegypti eggs, in accordance with the World Health Organization recommendations. The larvicidal and pupicidal LC50 values were 1.0 ppm and 20.3 ppm after 72 h, respectively. The oil maintained its activity in simulated field trials, killing all larvae and pupae at the tested concentrations. At 100 ppm, garlic oil inhibited 59.6 ± 10.6% of egg hatching. Toxicity against the adult form was observed as was its potent spatial repellency. Garlic oils composed of different diallyl polysulfide ratios did not significantly impact insecticidal activity although the garlic oil polysulfide mixtures were more potent than the individual polysulfides. The ovicidal, larvicidal, pupicidal, adulticidal and repellent assays showed the broad activity of garlic oil against Ae. aegypti. These results, together with the activity in simulated field trials, support the applicability of garlic oil in integrated mosquito vector control programs.