Insecticidal activity of single essential oil constituents against two stored-products insect pests

The exploration of plant-based natural products, particularly essential oils (EOs), as alternative control methods, arise due to challenges associated with the prolonged reliance on synthetic insecticides. Despite their promising activity, EOs use faces some challenges, mainly related to their standardization. This study investigates the exploration of some single chemical compounds commonly present in several EOs with insecticidal activity as candidate insecticides, specifically limonene, citral, beta-caryophyllene, and methyl salicylate. Chemicals were tested in toxicity bioassays toward Stegobium (St.) paniceum and Sitophilus (Si.) oryzae. The results showed that, among chemical tested, methyl salicylate and citral consistently exhibited high toxicity toward both the tested species. Calculated Lethal Time 50 (LT50) at the dose of 1 mg, for St. paniceum was 9.13 and 27.36 h from the treatment for citral and methyl salicylate respectively. Differently, for Si. oryzae the LT50 was higher than seven days at the 1 mg dose. However, the LT50 of adults treated with 10 mg dose of methyl salicylate was inferior to one hour, while for citral was of 4.45 h. The study reveals a dose-dependent impact on mortality, underscoring the compounds' potential for targeted pest management and offering crucial insights into their nuanced insecticidal effects for the development of tailored formulations with enhanced reliability and effectiveness in pest control strategies.