Novel devices and biomaterials for testing effective oviposition deterrence in Aedes aegypti

Aedes aegypti is a species of mosquito of great importance in the transmission of arboviruses throughout the world. Their eggs have high survivability in inhospitable environments because they are resistant to desiccation. One of the forms of control of this species is interference in the oviposition of females in places that can be potential breeding sites. Essential oils can serve as repellents by decreasing egg laying and, consequently, mosquito density. Several species of plants that produce essential oils have shown promise for the control of pests and insects. However, their volatilisation can be a limiting factor for use in large spaces. This study investigated whether citronella essential oil microencapsulated in carnauba wax affects the oviposition of female Ae. aegypti mosquitoes. The microcapsules were characterised by scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis and differential scanning calorimetry together with an oviposition bioassay of Ae. aegypti females. In the multiple-choice oviposition assays and in the assays with no choice, the microcapsules showed a repellent effect. Hence, the tested microcapsules have oviposition deterrent potential in Ae. aegypti females. As a solution, carnauba wax can serve as a base for microencapsulation of these essential oils, prolonging the action of citronella and not affecting nature, given that its components are biodegradable and biocompatible.