Estudo da atividade inseticida e repelente de Pelargonium graveolens L’Her (geraniaceae) nos diferentes estágios de vida do Aedes aegypti L. (diptera: culicidae)

Abstract

The Aedes (Stegomyia) aegypti mosquito is considered a major public health problem, since it is the main vector of dengue, chikungunya and zika viruses. Efficient vaccines against these viruses have not yet been developed. In this way, thevector control is the main form of combat. Several studies have shown that the continuous application of chemical agents has led to resistance in mosquitoes, in addition, the use of these products can have negative effects on human health and the environment, making it necessary to seek safer and more effective alternatives. One option for vector control is the use of compounds of natural products likeactive constituents from plant species, resulting in several studies carried out in Brazil and in the world. Perlagonium graveolens is a resistant tissue plant growing up to 1 meter tall. The essential oil of P. Graveolens is constantly used in the cosmetic industry, mainly in flavoring, but some studies also demonstrate repellent and insecticidal activity. Based on this context, the general objective of this study is to study the effects of the essential oil of Pelargonium graveolens in the different stages of life of Aedes aegypti. In this context, larvicidal, ovicidal, pupicid, adulticide and repellent tests were carried out at different concentrations based on protocols of the world health organization. As results, the the larvicidal activityof 100% was achieved at the concentration of 500 ppm.In the ovicidal activity,88.33% of the eggs become unviable after 25 days of exposure (500 ppm), in the pupicid activity there was a mortality of 90% (500 ppm) and in the evaluation of adulticidal activity there was a mortality of 80% of adult mosquitoes after body contact with a concentration of 500 ppm. The IRE was 0.35 showing the repellent activity of Perlagonium graveolens essential oil at a concentration of 1000 ppm. Tests were also carried out for the experience of nitric oxide production and evaluation of cytotoxicity. After 24 hours of exposure to CL 50 (181.5 ppm), the hemolymph of larvae (L4) of Aedes aegypti was collected, where there was a marked decrease in the production of nitric oxide. In the cytotoxicity assay was possible to identify the prevalence of types of hemocytes and also to verify viable (not stained) and non-viable (stained) cells through the Annexin V (FITC) and propidium iodide (PI) marking methods. In addition of the presence of apoptotic and necrotic cells, doubly labeled cells were also finded, being designated as cells in the process of secondary necrosis. In conclusion, the essential oil of Pelargonium graveolens proved to be a potential insecticide and repellent against Aedes aegypti mosquito.