Aedes aegypti mosquitoes are the primary vectors of Zika virus and Dengue virus and represent a massive threat to public health worldwide. There are between 50-100 million cases of Dengue fever every year, and the geographical distribution of the Zika virus continues to increase rapidly. Extensive use of insecticides for mosquito-borne disease control led to the development of insecticide-resistant mosquito populations, and there is need for the development of new insecticidal formulations. For this investigation, we measured the relative toxicities of commercial insecticides azinphos-methyl and chlorfenapyr via topical applications. After determining the relative toxicities, we screened mixtures of each compound with various natural plant oils in order to assess their ability to enhance insecticidal effectiveness. We previously demonstrated plant oils possess promising enhancement features when combined with various types of pesticides against Aedes aegypti. Through this study, we found a significant increase on toxic activity in the natural plant oil mixtures. Hence, the increased efficacy of azinphos-methyl and chlorfenapyr when combined with plant oils may contribute to the development of environmentally favorable formulations. Ultimately, plant oil mixtures may be used as part of global efforts toward controlling Aedes aegypti populations, and the spread of Dengue virus and Zika virus.