Design and evaluation of deltamethrin‐based microemulsion formulation to control Aphis gossypii (Hemiptera: Aphididae)

Abstract

A microemulsion is a stable, homogeneous pesticide formulation, based on an aqueous solvent, which is considered as a suitable alternative to emulsion formulations. In this study, microemulsion formulations of deltamethrin insecticide were designed to control Aphis gossypii Glover (Hemiptera: Aphididae), one of the important pests of many crops and ornamental plants. The solvent was selected based on the higher solubility of deltamethrin, and the appropriate surfactants were selected based on the quality of microemulsion formation. Pseudo‐ternary phase diagrams were constructed by the water titration method. The microemulsion systems were prepared using mixtures composed of deltamethrin, surfactants including Kenon 10 + SDS, Tensiofix 8427 + SDS and Tensiofix 8427 + SLS, and cosurfactant (1‐butanol). The Physico‐chemical properties of the obtained microemulsions were also evaluated. The appearance of microemulsion systems was transparent, and the droplet size of all samples was less than 20 nm. The formulations showed thermodynamic stability and low viscosity. All four microemulsion formulations had high insecticidal activity against A. gossypii, compared with an aqueous solution of pure deltamethrin. In this study, an environment‐friendly microemulsion system was designed to improve the efficacy of deltamethrin for controlling populations of A. gossypii. However, further research could be performed to assess the behaviour and ultimate fate in the environment prior to commercialization.