The mosquito Aedes aegypti L. (Diptera: Culicidae) is a vector of arboviral diseases such as dengue fever. Currently, the main approach to mosquito control is the application of synthetic insecticides, which can lead to negative environmental impacts and insecticide resistance in mosquito populations. As such, there has been increased interest in developing alternative methods for control of vector populations such as utilizing plant compounds that act as larvicides. The aim of this work is to evaluate the effectiveness of Eucalyptus sp. (Myrtaceae) essential oils for control of Ae. aegypti larvae. The essential oils of seven Eucalyptus species and hybrids were extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry. The essential oils were further diluted in water with acetone (0.40%) at the following concentrations: 100, 50, 25, and 10 μg ml−1. Mortality trials were conducted in plastic containers with a solution of ultrapure water and 200 μl of diluted oil for a total volume of 50 ml per treatment. The experiments for each Eucalyptus species/hybrid and concentration were performed in triplicate, using a control containing only water and acetone. Twenty larvae were added to each container and mortality was recorded at 1, 2, 4, and 24 h. The Eucalyptus essential oils showed larvicidal activity in most of the evaluated concentrations, mainly at 50 and 100 μg ml−1. Eucalyptus benthamii Maiden & Cambage and the hybrid Urograndis displayed the highest larvicidal potential (100% at 24 h) in the 100 μg ml−1 treatment. Larval mortality of Ae. aegypti showed a positive correlation with the compounds γ‐, o‐cymol, o‐cymene, terpineol, 3‐dodecylfuran‐2,5‐dione, α‐pinene, globulol, and ledol. The most abundant compounds identified in the essential oils were 1,8‐cineole and α‐pinene. These results highlight the potential of using Eucalyptus essential oils for the isolation of natural larvicidal products.

中文翻译：

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化学问题：桉树精油对蚊子幼虫死亡率的生物活性

蚊子 Aedes aegypti L.（双翅目：Culicidae）是登革热等虫媒病毒疾病的载体。目前，控制蚊子的主要方法是使用合成杀虫剂，这可能导致对环境的负面影响和蚊子种群的杀虫剂耐药性。因此，人们越来越关注开发控制载体种群的替代方法，例如利用植物化合物作为杀幼虫剂。这项工作的目的是评估 Eucalyptus sp. 的有效性。（桃金娘科）用于控制 Ae 的精油。埃及伊蚊幼虫。七种桉树和杂种的精油通过水蒸馏提取，并通过气相色谱与质谱联用进行分析。精油进一步在水中用丙酮（0. 40%) 在以下浓度：100、50、25 和 10 μg ml-1。死亡率试验在装有超纯水和 200 μl 稀释油溶液的塑料容器中进行，每次处理的总体积为 50 ml。每种桉树物种/杂交种和浓度的实验一式三份进行，使用仅包含水和丙酮的对照。每个容器中加入 20 只幼虫，并在 1、2、4 和 24 小时记录死亡率。桉树精油在大多数评估浓度下都显示出杀幼虫活性，主要在 50 和 100 μg ml-1。Eucalyptus bethamii Maiden & Cambage 和杂种 Urograndis 在 100 μg ml-1 处理中显示出最高的杀幼虫潜力（24 小时为 100%）。Ae的幼虫死亡率。aegypti 与化合物 γ-、o-cymol、o-cymene、萜品醇、3-十二烷基呋喃-2,5-二酮、α-蒎烯、球蛋白醇和利多醇。在精油中鉴定出的最丰富的化合物是 1,8-桉树脑和 α-蒎烯。这些结果突出了使用桉树精油分离天然杀幼虫产品的潜力。