Insecticidal Efficacy and Repellency of Trans-Anethole Against Four Stored-Product Insect Pests

In this study, it was investigated that repellency and insecticidal efficacy of trans-anethole of botanical origin on major stored product on pests species, namely Sitophilus granarius (L.) (Coleoptera: Curculionidae), Sitophilus oryzae (L.) (Coleoptera: Curculionidae), Tribolium confusum Jacquelin du Val (Coleoptera, Tenebrionidae) and Tribolium castaneum (Herbst) (Coleoptera, Tenebrionidae). Repellency effect was evaluated by choice test in petri dishes, while the mortality effect was examined by exposure to wheat treated at different concentrations, such as 1, 2, 3, 4, and 8 μL trans anethole. In efficacy tests, after 72 hours exposure, the highest adult mortality was found on T. castaneum with a 60% mortality, while other test species showed no significant mortality. On the other hand, repellency tests revealed varying degree of repellency depending on the application dose of trans-anethole. It was determined that S. granarius belongs to repellent class III, while all of the other species fall under repellent class IV. F1 progeny decreased as trans-anethole concentration increased, and in this context 8 μL of trans-anethole is proved to be the optimal concentration causing maximum decrease in progeny production. Among the insect species tested, T. confusum was found to be the most sensitive to trans-anethole with 100% decrease in F1 progeny production. Our results indicate that trans-anethole can be used as a potential repellent for the control of major stored grain pests. Additionally, trans-anethole, by its contact efficacy, might be considered as a grain protectant against S. granarius, S. oryzae, T. confusum and T. castaneum.