Valorization as bioinsecticide of the essential oils of two indigenous lavender species in Morocco: Lavandula stoechas and Lavandula pedunculata

Abstract

Aromatic and medicinal plants contain essential oils, which have an antifungal, bactericidal, antitoxic, insecticidal and insect repellent properties, etc. The aim of this work is a interspecific comparison of two Moroccan species belonging to the Lamiaceae family (genus: Lavandula): Lavandula stoechas and Lavandula pedunculata. The aim is to reveal the morphological confusion existing between them and the valorization of their essential oils, as bioinsecticide. The results obtained showed that the extraction of essential oils from the aerial part, obtained by hydrodistillation showing a high profitability in L. pedunculata. The tests of the insecticidal activity of these oils with the adults of Tribolium castaneum, (Tenebrionidae), showed that the essential oil of Lavandula stoechasa exhibited an important insecticidal and repulsive activity, which exceed the essential oil of Lavandula pedunculata. The lethal times 50 and 99 (LT50 and LT99) recorded from tests with Lavandula stoechas oil are lower to those obtained in Lavandula pedunculata for the whole range of concentrations used, which confirms that the first essence is very active compared to the second.