Composition and toxicity of rough lemon (Citrus jambhiri Lush.) rind essential oil against red flour beetle

One of the most destructive beetles attacking stored grain products in the tropics is red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae). The ecological problems associated with using synthetic chemical insecticides have strongly necessitated the need to search for biorational alternatives. The aim of this experiment was to evaluate the chemical composition and the insecticidal potentials of rough lemon (Citrus jambhiri Lush.) fruit rind essential oil (EO) against the pest. The EO obtained via hydrodistillation was assayed against T. castaneum at 27, 53, 80 and 107 mL/L air. Chlorpyrifos was used as a positive control. The EO was subjected to Gas chromatography-Mass spectrometry. A total of 51 compounds, predominated by oxygenated monoterpenes, were identified. The predominant ones included α-Terpineol (8.03%), Lemonol (7.67%) Citral (7.00%), 4-Terpineol (6.52%), n-hexadecanoic acid (4.70%), Caryophellene (4.58%), Citronellol (4.38%) and β-Bisabolene (4.01%), α-Bergamotene (3.74%), and Precocene I (3.33%). Application of the EO at 80–107 mL/L air evoked toxicity (53.75–100.00%) which compared with what was observed in insects treated with Chlorpyrifos (70.00–100.00%). The median lethal time (LT50) observed when the EO was applied at the rate of 80 μL/L air [1.11 (0.00–2.48 h)] was not significantly different from 0.70 (0.16–1.12) h observed when the EO was applied at 107 μL/L air and 0.62 (0.39–1.39) h observed when Chlorpyrifos was applied. The results of this study indicate the potential of the EO as an alternative to over-dependence on synthetic pesticides in the management of red flour beetle.