Insecticidal and AChE inhibitory activities of Matricaria chamomilla var. recutita essential oils collected from different regions against storage insect pests

The essential oils of the flowers of Matricaria chamomilla var. recutita from İstanbul and Bursa were analyzed by GC-MS. The essential oil yields were 0.32 and 0.18 v/w, respectively. The main components of the essential oil of the İstanbul sample were bisabolene oxide (41.81%), (E)-β-Farnesene (7.52%), and bisabolol oxide B (3.18%). The main components of the oil from the Bursa sample were bisabolol oxide A (47.76%), (E)-β-Farnesene (12.75 %), bisabolol oxide B (3.47%), and bisabolene oxide (2.46%). The fumigant and contact insecticidal effects of these oils were determined against Sitophilus granarius, S. oryzae (Coleoptera: Curculionidae), Tribolium confusum, and T. castaneum (Coleoptera: Tenebrionidae). Additionally, the ovicidal effect of the oils was tested against T. confusum and Oryzaephilus surinamensis (Coleoptera: Silvanidae). The highest fumigant toxicity was observed against S. granarius, S. oryzae, and T. confusum (74.9–96.6% mortality) at the 20% application dose. The fumigant effect of the oils against T. castaneum was lower than the effect observed for other insect species. The highest contact toxicity was observed against S. granarius and S. oryzae (100% mortality) at a 100 μL/mL application dose. In terms of ovicidal efficacy, the oils obtained from Istanbul and Bursa were 19.7–37.7% effective on T. confusum eggs, while this ratio was 53.4–48.3% on O. surinamensis, respectively. Acetylcholinesterase inhibition of the oils was also investigated, and both oils produced mediocre activity.