Insecticidal potential of cinnamon oil against cigarette beetle, Lasioderma serricorne (Fabricius) and rice moth, Corcyra cephalonica (Stainton) infesting stored products

Grain storage leads to significant losses due to insect pests, degrades grain quality and increases the risk of mould infestations. The cigarette beetle (Lasioderma serricorne) and the rice moth (Corcyra cephalonica) are cosmopolitan pests that attack various dried plant products, including grains like rice, sorghum, maize and cotton seed. In organic grain storage, synthetic pesticides are prohibited due to their toxicity. As an alternative, essential oils from aromatic plants have shown promise. Cinnamon (Cinnamomum spp.) oil, particularly, has demonstrated insecticidal properties against stored insect pests. This study aimed to evaluate the efficacy of cinnamon oil against L. serricorne and C. cephalonica adults. Cinnamon oil was extracted from cinnamon bark and analyzed using GC–MS, identifying (E)- Cinnamaldehyde (51.16 %), acetic acid and cinnamyl ester (9.67 %) as the primary compounds. The contact toxicity of the cinnamon oil was tested against adult L. serricorne and C. cephalonica at concentrations ranging from 80 to 400 µL/cm². The results showed that higher oil concentrations and longer exposure durations significantly increased toxicity. The LC50 values for L. serricorne were 260.65, 149.15 and 98.67 µL/cm² after 24, 48 and 72 hrs, respectively. For C. cephalonica, the LC50 values were 285.60, 160.08 and 109.33 µL/cm² at the same time intervals. The LT50 values at 400 µL/cm² were 20.34 hrs for L. serricorne and 21.43 hrs for C. cephalonica. Cinnamon oil proved highly effective, suggesting its potential as a botanical insecticide for managing these pests with minimal environmental impact.