Study of toxicity and nutritive indicators of herbal essential oils of cinnamon, peppermint and Eucalyptus against different stages of Elm Leaf Beetle Xanthogaleruca luteola (Coleoptera:Chrysomelidae) in vivo

Elm leaf beetle is one of the most important pests of Elm trees at adult stage and especially at larval stages. In this research work, the contact toxicity and nutritive indicators of Cinnamon, Peppermint, and Eucalyptus have been investigated. The experiments were performed in five densities with three repetitions for each essential and for each life stage of the elm leaf beetle at 25±1C0 and relative humidity of 60±5 percent for 16 hours in daylight and 8 hours in darkness in vitro. The results obtained from biometry data showed that with an increase in density of the essential oils, the mortality rate of elm leaf beetle at different stages of their life increased for all the three essential oils. Based on these results, the essential oil of Cinnamon proved to have the most effect at different stages of elm leaf insect by creating 80 percent mortality relative to the two essential oils of eucalyptus and peppermint after 24 hours. Furthermore, with an increase in the density of the essential oils, the nutritive indicators at the second. instar larva were also reduced. Statistical analysis of variance showed that the relative rate of second instar larva (PCR) in cinnamon essential oil in three concentrations of LC25, LC35 and LC50 compared with the control group was more meaningful compared with the two other essential oils at 5 percent and nutrition inhibition was positive for all the essential oils especially for cinnamon essential oil.  The findings indicate that Cinnamon essential oil compared to Peppermint, and Eucalyptus essential oils is a more suitable candidate to control this pest.