Evaluation of a quasi‐dimeric eugenol derivative as repellent against the stored grain insect pest Sitophilus oryzae (Coleoptera Curculionidae)

BACKGROUND Essential oils (EOs) and their chemical components are often proposed as an alternative to synthetic pesticides for pest control of foodstuff insect pests. However, their low persistence and strong, spicy odour, make them poorly suitable for use to protect food. Modification of the EOs components molecules increases their molecular weight and reduce their volatility. However, the effectiveness of such modified molecules has, so far, not been tested against stored food insect pests. In this study, the intensity and the duration of the repellence against the insect pest Sitophilus oryzae of a recently synthesized quasi-dimeric eugenol derivative (ED) (C18H20O4) were compared to those of eugenol and three eugenol related compounds. The hypothesis tested was that by its higher molecular weight and two functional groups the ED would overcome the low persistence and strong and spicy odour drawback of eugenol without compromising the repellence against insects. RESULTS The insect behavioural tests showed a greater repellence and persistence of ED than eugenol and the three eugenol related compounds against S. oryzae. The sensory analysis of ED by panel test indicated that ED is significantly less odorous than eugenol without any spicy nor balsamic nuances in its smell profile. CONCLUSIONS Because of its high repellence against insects and its low smell intensity for humans, ED could represent a valid repellent for the control of foodstuffs insect pests.