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The growing interest in the development of green pest management strategies is leading to the exploitation of essential oils (EOs) as promising botanical pesticides. In this respect, nanotechnology could efficiently support the use of EOs through their encapsulation into stable nanoformulations, such as nanoemulsions (NEs), to improve their stability and efficacy. This technology assures the improvement of the chemical stability, hydrophilicity, and environmental persistence of EOs, giving an added value for the fabrication of natural insecticides effective against a wide spectrum of insect vectors and pests of public and agronomical importance. <i>Carlina acaulis</i> (Asteraceae) root EO has been recently proposed as a promising ingredient of a new generation of botanical insecticides. In the present study, a highly stable <i>C. acaulis</i>-based NE was developed. Interestingly, such a nanosystem was able to encapsulate 6% (<i>w</i>/<i>w</i>) of <i>C. acaulis</i> EO, showing a mean diameter of around 140 nm and a SOR (surfactant-to-oil ratio) of 0.6. Its stability was evaluated in a storage period of six months and corroborated by an accelerated stability study. Therefore, the <i>C. acaulis</i> EO and <i>C. acaulis</i>-based NE were evaluated for their toxicity against 1st instar larvae of the European grapevine moth (EGVM), <i>Lobesia botrana</i> (Denis & Schiffermüller, 1775) (Lepidoptera: Tortricidae), a major vineyard pest. The chemical composition of <i>C. acaulis</i> EO was investigated by gas chromatography–mass spectrometry (GC–MS) revealing carlina oxide, a polyacetylene, as the main constituent. In toxicity assays, both the <i>C. acaulis</i> EO and the <i>C. acaulis</i>-based NE were highly toxic to <i>L</i>. <i>botrana</i> larvae, with LC₅₀ values of 7.299 and 9.044 µL/mL for <i>C. acaulis</i> EO and NE, respectively. The <i>C. acaulis</i>-based NE represents a promising option to develop highly stable botanical insecticides for pest management. To date, this study represents the first evidence about the insecticidal toxicity of EOs and EO-based NEs against this major grapevine pest.