خواص حشر‌ه‌کشی برخی از اسانس‌های گیاهی روی سوسک کشیش Rhyzopertha dominica (F.)، در شرایط آزمایشگاهی

The lesser grain borer, Rhyzopertha dominica F. is one of the important pests of cereal grains in storage and causes economically severe damage. Considering the need to use eco-friendly agents in insect pest management, in the current study, the toxicity of essential oils of savory (Satureja hortensis L.), clove (Syzygium aromaticum L.), peppermint (Mentha piperata L.), ajwain (Carum Copticum L.), anise (Pimpinella anisum L.), and fennel (Foeniculum vulgare Mill) was evaluated against the lesser grain borer. The extraction of essential oils was done using a Clevenger-type apparatus through hydro-distillation method. The toxicity of essential oils was evaluated by placing one-day-old adult males and females insects on wheat grains treated with different concentrations of essential oils (from 0.5 to 15 µl/g of savory, clove, peppermint, ajwain, anise and fennel essential oil). The results showed that the mortality of pest increased with increasing essential oil concentrations. The toxicity of savory and clove essential oils on the pest was higher than the others. The LC50 values of savory and clove essential oils were calculated as 5.98 and 6.39 µl/g after 24 h, which, respectively, decreased to 3.78 and 3.95 µl/g within 72 h. The results of the sublethal experiments after 72 hours showed that males and females’ longevity and the fecundity of females affected by LC30 values of savory and clove essential oils (respectively equal to 2.37 and 2.48 µl/g) were significantly lower than other treatments (P < 0.05). The net reproductive rate (R0), intrinsic rate of natural increase (r), and finite rate of increase (λ) of the pest in savory essential oil treatments were also significantly lower than others (P <0.05). Considering the low-LC50 values of savory and clove essential oils and their effects on the demographic parameters of the pest, the mentioned essential oils can be suggested as natural alternatives to chemical pesticides in the management of the lesser grain borer for further research.