Chemical compositions, Fumigant and Repellent Activities, of Essential oils from three Indigenous medicinal plants and their mixture, against stored grain pest, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

The chemical composition of the essential oils (EOs) of Artemisia herba-alba Asso, Rosmarinus officinalis L and Juniperus pheonicea L and its fumigant and repellent activities against Tribolium castaneum (Herbst) were investigated as well as their mixture. Dried leaves and flowers were subjected to hydrodistillation using a Clevenger-type apparatus and the chemical composition of the volatile oils was studied by gas chromatography- mass spectrometry (GC-MS). A total of 117 components were identified from the three EOs and their mixture. The main compounds identified for EOs of A. herba alba, R. officinalis, J. pheonicea and the mixture were Car- 3-en-5-one (12.51%), Camphor (34.37%), a-Pinene (15.49%), and camphor (13.95%), respectively. it Interestingly we discovered that the EO extracted from A. herba alba from Khenchela had a new chemotype with the appearance of new compounds in the mixture of EOs. Results of fumigant toxicity showed that after 24 h exposure time, all EOs had pronounced toxicity against T. castaneum, with LC 50value of 107.199, 155.724 and 156.589pl/l air for A. herba-alba, J. pheonicea and R. officinalis, respectively, while the LC50 of the mixture was 131.570pl/l air. However, at the concentration 2pl and after 30 min exposure time, the EOs of A. herba albaand J. phoenicea showed significantly more repellent effects up to 100.00±0.00 and 90.00±10.00%, respectively, followed by the mixture and the R. officinalis EO with the percentages of repulsion equal to 76.67±11.55 and 41.67±10.41% . Data analysis by CompuSyn showed that the synergy, antagonism or additive effect of the EOs in both tests depend on the concentration of the bioinsecticides and the exposure time. The results indicated that the tested EOs and their mixture had the potential to be developed as bioinsecticides and repellent for the control of T. castaneum adults.