LAUSR

BACKGROUND Plant essential oils (EOs) represent eco-friendly alternatives to conventional insecticides for managing pest populations. Carlina acaulis root EO showed a wide insecticidal spectrum, being highly effective against insect pests and vectors, coupled with low mammal toxicity. To boost the chemico-physical properties of this EO and its main active ingredient, carlina oxide, herein the C. acaulis EO was encapsulated into a nanoemulsion [NE, 6% EO (w/w)], evaluating its insecticidal properties against larvae and adults of Tribolium castaneum, Tribolium confusum and Tenebrio molitor. Two NE concentrations (500 and 1000 ppm) were applied on stored wheat. Mortality was determined after 4, 8 and 16 h and 1, 2, 3, 4, 5, 6 and 7 days. RESULTS The ΝΕ was toxic for the larvae of T. castaneum and T. confusum, by killing 93.9 and 98.9% at 1000 ppm after 7 days of exposure, respectively. T. molitor larvae were tolerant, since only 18.9% were dead after 7 days of exposure on stored wheat treated with 1000 ppm. However, the NE exhibited high adulticidal activity leading to 85.2% mortality at 1000 ppm, 7 days post-exposure. The mortalities of T. confusum and T. castaneum adults were low (i.e. 21.4 and 23.3% respectively) at 1000 ppm, 7 days post exposure. CONCLUSIONS The NE based on C. acaulis EO could be regarded as an efficacious green adulticide or larvicide, depending on the target insect species and its life stage, advancing and specifying the pest management strategies of the tested species in an eco-friendly way. This article is protected by copyright. All rights reserved.