Carlina acaulis root essential oil (EO) is one of the most potent mosquito larvicides (LC₅₀ < 2 ppm). This EO is mainly composed of carlina oxide (> 90%). Poor water solubility and rapid degradation from UV light and oxygen in the environment limit the real-world use of this EO. Herein, we developed nanocarrier-based formulations, namely micro- and nanoemulsions (ME and NE, respectively) containing C. acaulis EO or carlina oxide (both at 0.5%) as active ingredients (a.i.). The larvicidal activity of ME and NE was evaluated against Culex quinquefasciatus. The highest larvicidal activity was achieved by the ME containing 0.5% of the EO (M1); its LC₅₀₍₉₀₎ was 579.1 (791.3) µL L⁻¹. Sublethal effects of this ME and its a.i. were assessed testing both at the LC₁₆, LC₃₀, LC₅₀ and LC₉₀ on mosquito larvae exposed to each product for 1–7 h, and then monitoring mortality for 18 days. At variance with the EO, ME application, even at LC₁₆, led to 100% mortality at 18 days. The EO and its encapsulated form were scarcely toxic to human keratinocytes (HaCaT) and human fibroblast (NHF A12) cell lines. The acute toxicity of C. acaulis EO and its ME (M1) was also evaluated in Wistar rats through oral administration; EO LD₅₀ was 1098 mg kg⁻¹ bw, whereas its ME, even at 5000 mg kg⁻¹ bw (considered the upper testing limit to establish safety to mammals), was not toxic. This study highlights the outstanding efficacy of C. acaulis EO ME for developing long-lasting and safe larvicides against Cx. quinquefasciatus.

卡里纳金合欢根精油（EO）是最有效的蚊虫幼虫（LC ₅₀  <2 ppm）之一。该EO主要由氧化卡因（> 90％）组成。不良的水溶性以及环境中紫外线和氧气的快速降解限制了该EO在现实世界中的使用。在此，我们开发了一种基于纳米载体的制剂，即微乳液和纳米乳液（ME和NE，分别地）的含C. acaulis EO或卡利娜氧化物（均为0.5％）作为活性成分（AI）。ME和NE的杀虫活性，对评估致倦库蚊。含有0.5％EO（M1）的ME可以达到最高的杀幼虫活性。LC _50（90）为579.1（791.3）µL L ^-1。通过在LC ₁₆，LC ₃₀，LC ₅₀和LC ₉₀上对暴露于每种产品1-7 h的蚊虫幼虫进行评估，评估了该ME及其致死力的亚致死作用，然后监测了18天的死亡率。与EO，ME应用不同，即使在LC _16时，也导致18天时100％的死亡率。EO及其封装形式对人角质形成细胞（HaCaT）和人成纤维细胞（NHFA12）细胞几乎没有毒性。还通过口服给药在Wistar大鼠中评估了金毛茶EO和其ME（M1）的急性毒性。EO LD ₅₀为1098 mg kg ^-1 bw，而其ME即使在5000 mg kg ^-1时bw（考虑到建立对哺乳动物安全性的测试上限），无毒。这项研究凸显了金毛隐孢子虫EO ME在开发针对Cx的持久，安全的杀幼虫剂方面的杰出功效。quinquefasciatus。