Bio-insecticidal efficacy of four essential oils against adults of Sitophilus granarius (Coleoptera: Curculionidae) and larvae of Tenebrio molitor (Coleoptera: Tenebrionidae)

The bio-insecticidal efficacy of essential oils from anise (Pimpinella anisum L.), cumin (Carum carvi L.), fennel (Foeniculum vulgare Miller) and origanum (Origanum vulgare L.) essential oils was tested using adults of wheat granary weevil, Sitophilus granarius L. (Coleoptera: Curculionidae) and larvae of yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae), as the two representants of stored grain pests. From the essential oils used, cumin showed the highest bio-insecticidal efficacy by both types of tests. From the model organisms used, only adults of wheat granary weevil were affected, since yellow mealworm larvae did not respond nor to any of the essential oils used neither to test type. Essential oils seem to have strong potential to replace dangerous synthetic toxic insecticides, however, their efficacy seems to be strongly dependent on the target organisms as well as way of application.