Effect of the ethanolic extract of Pachygone ovata (Poir.) leaf extract on the viability of the egg and larva of Aedes aegypti (Diptera: Culicidae) in the laboratory conditions

Abstract

Numerous plant species are utilised as valuable biological resources because active ingredients are inside them, which have been effectively exploited as insecticides. Pachygone ovata (Poir.), a plant species, exhibited characteristics of being predominantly non-aggressive and environmentally benign. However, its capacity to effectively regulate insect populations, namely mosquitoes, remained little explored. Dengue fever is an infectious disease caused by the dengue virus, which is predominantly transmitted by mosquito bites from the Aedes genus, with Aedes aegypti being the primary vector. This study examined the effect of an ethanolic extract derived from the leaves of Pachygone ovata on the survival rates of Aedes (Stegomyia) aegypti (Diptera: Culicidae) eggs and larvae in the laboratory of Acharya Nagarjuna University. Aedes aegypti is the arthropod vector that transmits the viruses that cause dengue fever, Zika virus, and Chikungunya fever. The vector has proved resistant to organophosphate chemicals used to combat the disease globally. Eggs and fourth-stage larvae of Aedes aegypti were exposed to three distinct concentrations of an ethanolic extract derived from the plant of P. ovata (C_1 = 0.0017 g/ml, C_2 = 0.0034 g/ml, and C_3 = 0.0051 g/ml) in a bioassay. The egg viability was greater than 70% in all three concentrations, whereas the larval mortality rate was greater than 70% in C_3.