Investigation of effects of toxicity and healthy eating (nutritional) index of Cinnamomum, Rosmarinus officinalis L. and Lavandula angustifolia L. essential oils on biological stages of Xanthogaleruca luteola (Coleoptera: Chrysomelidae)

Xanthogaleruca luteola (Coleoptera: Chrysomelidae) is considered as one of the most important pests of Ulmus trees at the adult insect stage, especially at the larval stages. The effect of toxicity and nutritional indicators of essential oils of Cinnamomum zeylanicum L., Rosmarinus officinalis L. and Lavandula angustifolia L. on different biological stages of X. luteola investigated under standard environmental conditions. Four replications were considered and after 24 hours, losses were counted. LC50 values for toxicity of C. zeylanicum L., R. officinalis L. and L. angustifolia L. essential oils on adult X. luteola were estimated to be 11.57, 28.83 and 737.87 ppm, respectively, indicating that Cinnamomum essential oil is more toxic than other essential oils. With increasing concentrations of essential oils, eating indicators of second-instar larvae reduced. The relative consumption rate (RCR) of second-instar larvae in Cinnamomum essential oil at concentrations of LC25, LC35 and LC50 showed a significant difference with the control treatment at the level of 5%. The results of essential oil analysis showed that cinnamaldehyde (91.8%), 1, 8-cinnamol (37.8%) and borneol (8.4%) are the predominant compounds in C. zeylanicum L., R. officinalis L. and L. angustifolia L. essential oils, respectively. Increased nutritional inhibition in Cinnamomum essential oil compared to R. officinalis L. and L. angustifolia L. essential oils can be attributed to the strong toxicity of cinnamaldehyde available in this essential oil. The study results show that Cinnamomum essential oil is a more suitable option for controlling this pest than R. officinalis L. and L. angustifolia L. essential oils.