Multiple Insecticidal Effects of Terpene-Rich Essential Oils from Satureja intermedia, Thymus vulgaris, and Zataria multiflora Against Callosobruchus maculatus (F.)

Abstract

The detrimental side effects of synthetic chemicals in managing insect pests have led researchers to create environmentally friendly and effective alternatives. The insecticidal potential of essential oils isolated from three available aromatic plants, Satureja intermedia, Thymus vulgaris, and Zataria multiflora, was assessed for their effects on Callosobruchus maculatus. Chemical analysis indicated that essential oils contain a high percentage of terpenic compounds, dominated by carvacrol, thymol, and p-cymene. Acute toxicity assays revealed significant toxicity, with 72 h LC50 (lethal concentration to kill 50% of the tested insects) values of 0.16 μL/g for S. intermedia, 0.10 μL/g for T. vulgaris, and 0.10 μL/g for Z. multiflora against adults of C. maculatus. Treatment with the 24 h LC30 and LC50 of essential oils significantly extended the developmental and preoviposition periods while reducing the fecundity and longevity of adults. The demographic parameters, including the intrinsic rate of increase (r), gross reproductive rate (GRR), net reproductive rate (R0), and finite rate of increase (λ), were also significantly decreased by exposure to essential oils. On the basis of their acute toxicity and chronic effects on life history parameters, S. intermedia, T. vulgaris, and Z. multiflora essential oils have high potential for managing C. maculatus.