اثرات کشندگی و زیرکشندگی برخی از اسانس‌های گیاهی روی شب‌پره مدیترانه‌ای آرد، Ephestia kuehniella Zeller

Pondering the numerous side effects of chemical insecticides, the use of environmentally friendly natural compounds in pest control has attracted the attention of researchers. In the current study, the lethal and sublethal effects of essential oils of peppermint (Mentha piperata L.), savory (Satureja hortensis L.), ajwain (Carum Copticum L.), fennel (Foeniculum vulgare Mill), clove (Syzygium aromaticum L.), and anise (Pimpinella anisum L.) were studied on Mediterranean flour moth, Ephestia kuehniella Zeller. The possibility of augmentation of the toxicity of the mentioned essential oils by their combination was also studied. Bioassays were performed at six concentrations (1100 to 5000 ppm) within 24, 48, and 72 h by placing fifth instar larvae (48 h old) of Mediterranean flour moth on the treated wheat flour. The savory and ajwain essential oils were showed higher toxicity than the others on the pest. After 24 h exposure, LC50 values of savory and ajwain essential oils were calculated as 3357.04 and 3506.30 ppm, respectively which decreased to 1559.62 and 2005.81 ppm, respectively after 72 h. On the other hand, the susceptibility of the insect pest to essential oils was increased by increasing the time. Operating the LC30 values of savory and ajwain essential oils (1005.75 and 1460.81 ppm, respectively) after 72 h resulted in a significant reduction in the survival percentage of larvae, the lifespan of female insects, the number of eggs laid, and the percentage of egg hatching compared to the control. The combination of LC30 values of clove-fennel and anise-ajwain essential oils had an additive effect on pest mortality. The interaction of essential oils in other combinations had synergistic effects, increasing the mortality percentage of larvaes. The results of the present study display that the essential oils of savory and ajwain have a high potential in Mediterranean flour moth management, and they can be considered as low-risk and efficient alternatives to chemical insecticides for further research.