Susceptibility and alterations by diflubenzuron in larvae of Aedes aegypti.

Abstract

Benzoylphenyl ureas inhibit chitin synthesis and interfere with the molting process in arthropods. In this study, the effect of diflubenzuron on third-instar larvae of Aedes aegypti was evaluated. The susceptibility to the product was determined, and the alterations generated were shown through light and electron microscopy. LC50 and LC90 were 0.23 and 0.47 ppm, respectively. The main alterations observed were the incapacity to complete the molt, a reduction of mobility, the fragmentation of the old cuticle, a division of the body segments that was not evident, and the deformation of the caudal structures. Images of the ultrastructure are included, where breaking zones in the cuticle were observed, separation of the cuticle, the epidermis and the muscles, and these latter with a disorganized arrangement. In low concentrations, from 0.15 ppm, diflubenzuron causes alterations in the behavior and morphology of Ae. aegypti.