The present study was designed to determine chemical composition of essential oils extracted from different species of the Myrtaceae family and to evaluate their insecticidal activities against Tribolium castaneum (Coleoptera: Tenebrionidae). The essential oils of 10 species were extracted by hydrodistillation and analyzed by a gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The main component of Eucalyptus crebra, E. microtheca, E. rudis and Melaleuca quinquenervia essential oils was 1,8-cineole (31.6-49.7%). E. melanophloia and E. tereticornis contained p-cymene (41.8-58.1%) as a major component, while Eucalyptus kitsoniana and E. pruinosa essential oils were dominated by α-pinene (25.8-31.4%). Eugenol methyl ether was identified as a major component in M. bracteata essential oil (82.3%). α-Pinene (31.4%) was the main component in the C. viminalis essential oil. Essential oils of all selected plant species showed good insecticidal activities against T. castaneum when compared with pyrethroid as a positive control. Eucalyptus rudis proved most potent against T. castaneum, followed by M. bracteata, M. quinquenervia, and C. viminalis. The results of this study indicate that essential oil of Myrtaceae leaves have potential to be used in the control of T. castaneum.

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Better plant growth of crop plants has been a major concern of mankind since antiquity. Indole acetic acid is one of the natural plant growth regulators studied in plant sciences for a long time, followed by cytokinins, ethylene, gibberellic acid, and others that were discovered later. Indole acetic acid is responsible for promoting root growth while cytokinins like zeatin are considered specialized for shoot growth [1]. Later on, the attention of scientists was diverted toward commercial production of