Chemical composition and insecticidal efficacy of Cyperus rotundus essential oil against three stored product pests

In recent years, the use of plant derivatives such as essential oils has been considered as a substitute for chemical pesticides in pest control. Essential oil of Cyperus rotundus L. rhizomes was extracted by hydrodistillation and its compounds were identified by GC/MS. Also, the contact toxicity and repellent activity of essential oil against adults Callosobruchus maculatus F., Oryzaephilus surinamensis L., and Trogoderma granarium Everts were evaluated in the laboratory (27 ± 2 °C, 65 ± 5% relative humidity, and dark conditions). The results showed that elemenone (13.59%), α-cyperone (13.14%), and caryophyllene oxide (13.03%) were the major constituents of essential oil. The values of LC50 for C. maculatus, O. surinamensis, and T. granarium in contact toxicity were 0.36, 0.51, and 0.2 μL/cm2, respectively. The repellency percentage of essential oil on O. surinamensis, T. granarium, and C. maculatus was 94%, 94%, and 80% after 2 h, and 90%, 92% and 70% after 4 h, respectively. According to these results, essential oil of C. rotundus can be used as a suitable substitute for chemical pesticides to protect the stored products against pests. •Sesquiterpens are the major components of the essential oil of C. rotundus rhyzomes.•Elemenone (13.59%), α-cyperone (13.41%), and caryophyllene oxide (13.03%) are the most important sesquiterpenes of the oil.•The essential oil of C. rotundus also contained monoterpenes (15.06%).•The highest repellency (94%) was at the concentration of 0.04 μl/cm2 after 2 hours for O. surinamensis and T. granarium.•Contact toxicity of C. rotundus essential oil differs for various stored product pests.