Adulticidal, Ovicidal and Repellent Activity of Zno and Tio2 Nps against Anopheles Stephensi, Aedes Aegypti and Culex Quinquefasciatus

Abstract

Synthetic insecticides are used to control mosquitoes, but in the process, they contaminate soil, water, and air. They also have side effects on populations that are not intended targets, particularly humans, and in recent years, resistance to these insecticides has grown significantly. Inorganic nanoparticles such as zinc oxide (ZnO) and titanium dioxide (TiO₂) are far safer for humans and animals. Therefore, the current study was aimed to evaluate the adultcidal, ovicidal and repellent activity of ZnO and TiO₂ nanoparticles, in combination, against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The adulticidal activity was performed at 3, 6, 9, 12 and 15 ppm of a combination of ZnO and TiO₂ NPs. The adult mortality values of LC₅₀ were 4.415, 4.585, and 4.757, respectively, while the LC₉₀ mortality values were 11.159, 12.778, and 14.168 for An. Stephensi, Ae. aegypti and Cx. quinquefasciatus, respectively. In combination, the selected mosquitoe eggs were treated with ZnO and TiO₂ NPs at concentrations of 2, 4, 6, 8 and 10 ppm. The egg hatchability rate was found to be good at 8 and 10 ppm. The repellent activity was performed at different concentrations, i.e., 0.5, 1 and 1.5 mg/cm², at various intervals viz., 2, 4, 6, 8, and 10 hours. All the selected concentrations showed good repellent activity for up to 6 hours, but 1.5 mg/cm² showed a prominent repellent effect against the selected mosquitoes. Thus, the present results confirmed that ZnO and TiO₂ NPs, in combination, possess the potential to manage mosquito populations.