Chemical composition of essential oil from Lavandula dentata L. to control citrus aphids selectively

The green citrus aphid (Aphis spiraecola) is a major pest in Mediterranean citrus orchards, transmits phytoviruses, and shows increasing resistance to synthetic insecticides. This study aimed to evaluate the chemical composition and aphicidal activity of essential oil (EO) from Lavandula dentata and to assess its selectivity toward beneficial insects. EO was extracted by hydrodistillation from leaves and analyzed using gas chromatography-mass spectrometry, yielding 1.8% of the dry biomass. The major constituents were monoterpenes (45.5%) and sesquiterpenes (22.4%), with eucalyptol (12.8%), β-pinene (5.7%), linalool (4.7%), camphene (4.4%), murolan-3,9 (11)-diene-10-peroxy (4.3%), and α-pinene (4.0%) as dominant compounds. The oil exhibited significant contact insecticidal activity against A. spiraecola. After 24 h, LD₅₀ and LD₉₀ values were 6.02 and 23.56 µL mL^⁻1, respectively. At 48 h, LD₅₀ decreased to 0.16 µL mL^⁻1. and LD₉₀ to 20.02 µL mL^⁻1, while at 72 h, values reached 0.07 and 3.39 µL mL^⁻1, respectively. Exposure to an LD₉₀ of 20.02 µL mL^⁻1 for 48 h on aphids caused no adverse effects on key aphid predators (ladybird beetles, cecidomyiid, and chrysopid larvae) or adult honeybees.