Oil in water (o/w) emulsions stabilized by an amphiphilic copolymer have been studied in relation to their potential insecticidal activity against Aedes aegypti mosquito larvae. These emulsions contain as the oil phase different blends of two isomeric essential oil compounds, thymol and carvacrol. The results show that the addition of carvacrol facilitates the dispersion of the oil within the aqueous phase, with the stabilization and polydispersity of the emulsions being controlled by the change of the ratio between the copolymer concentration and that of the oil phase (R_cop/EOC). Emulsions containing pure essential oil compounds as the oil phase do not present any significant difference on their larvicidal activity against mosquito larvae, with emulsions containing only thymol being slightly more effective than those containing only carvacrol as the oil phase. Furthermore, the use of blends containing different weight fractions of thymol and carvacrol as the oil phase results in formulations with an additive larvicidal activity in relation to those with the pure compounds. Despite the larvicidal activity of the emulsions, they do not provoke inhibition to the emergence of adult individuals in A. aegypti populations. The spreading and evaporation of the emulsions onto the solid surface, which may be an important parameter for the performance of larvicidal formulations, were found to be dependent on the same parameters that govern the stability of the emulsions. This study helps in seeking new alternatives for the preparation of new eco-sustainable formulations against insect pests.

中文翻译：

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基于香精油化合物控制埃及伊蚊幼虫的环境友好型杀幼虫剂的开发：理化性质与杀虫活性之间的关系

对于两性共聚物稳定的水包油型乳剂，它们对埃及伊蚊的幼虫具有潜在的杀虫活性。这些乳液含有两种异构体香精油化合物百里酚和香芹酚的不同混合物作为油相。结果表明，香芹酚的添加促进了油在水相中的分散，通过改变共聚物浓度与油相之间的比率（R _{cop / EOC）}来控制乳液的稳定性和多分散性）。含有纯精油化合物作为油相的乳液在杀灭蚊子幼虫的杀幼虫活性上没有任何显着差异，其中仅含有百里酚的乳液比仅含有香芹酚作为油相的乳液更为有效。此外，使用含有不同重量百分数的百里香酚和香芹酚的共混物作为油相导致制剂具有相对于纯化合物而言具有附加杀幼虫活性的制剂。尽管乳剂具有杀幼虫活性，但它们并未引起抑制埃及埃及按蚊成年个体的出现。人口。发现乳剂在固体表面上的铺展和蒸发可能是杀幼虫剂制剂性能的重要参数，它取决于控制乳剂稳定性的相同参数。这项研究有助于寻找新的替代方法来制备新的生态可持续配方，以对抗害虫。