With the aim of helping to improve cashew production by reducing the major pests of this crop, the profile of the essential oil of Ocimum canum was characterized, along with its insecticidal potential against adults of Diastocera trifasciata, one of the major pests of the cashew tree. The essential oils were extracted by hydrodistillation from fresh leafy stems and fruits, and chemical analyses were performed using GC (IR) and GC-MS. For the efficacy tests conducted at the Agricultural Production Improvement Laboratory of University Jean LOROUGNON GUEDE in Daloa, concentrations (0.04 g/mL, 0.05 g/mL, 0.07 g/mL, 0.12 g/mL, and 0.37 g/mL) were sprayed directly onto the insects in a controlled environment. Analysis of the chemical composition showed that the essential oil extracted from the leafy stems and fruits with a yield of 0.45% consists primarily of 1,8-cineole (49.7%) and camphor (15.4%). Test results revealed that the essential oil of O. canum possesses promising insecticidal properties. It caused 100% mortality of adult leaf miners at concentrations of 0.12 g/mL and 0.37 g/mL on the first day after spraying. The measured LC₅₀ and LC₉₀ values were 5.39 × 10⁻² g/mL and 8.21 × 10⁻² g/mL, respectively. Field trials will be necessary to confirm this preliminary result with a view to developing a biodegradable pesticide against this beetle.