Acaricidal activity of the chinaberry, Melia azedarach L. (Lamiaceae) essential oil against Tetranychus urticae Koch

The two-spotted spider mite, Tetranychus urticae Koch, is the worst pest for strawberries among all arthropod pests in Iran. In this study, essential oils from the flowering branches and fruits of the chinaberry, Melia azedarach L. were analysed using gas chromatography-mass spectrometry, and the acaricidal activity of the oil was evaluated in fumigation tests against T. urticae. Forty-three constituents were identified and Methanecarbothiolic acid (10.80%), Ethyl Acetate (9.24%), 2-Propanone, 1-fluor (9.01), Acetic acid, 1-methylethyl ester (8.33%) and n-Propyl acetate (8.02%) were the main constituents The mites were susceptible to the oil using the fumigation method. The results stated that M. azedarach oil had high toxicity on eggs and adults of two-spotted spider mite (LC50 was 18.27 and 13.63 mu L L-1 for eggs and adults, respectively) with LT50 of 12.05 h. In addition, all tested concentrations had oviposition deterrent activity and repellency on adults of this mite. For the practical use of this oil as a novel acaricide, however, further investigations are needed to evaluate the effects on non-target organisms and the cost-benefit ratio for the formulation of a product to be used on protected crops such as strawberry in the greenhouse condition.