Chemical composition and acaricidal effects of essential oils of Foeniculum vulgare mill

Utilization of synthetic acaricides causes negative side-effects on nontarget organisms and environment and most of the mite species such as two spotted spider mite, Tetranychus urticae Koch, are becoming resistant to these chemicals. In the present study, essential oils of fennel, Foeniculum vulgare Mill., and lavender, Lavandula angustifolia Miller, were hydrodistilled using Clevenger apparatus and chemical composition of these oils was analyzed by GC-MS. Anethole (46.73%), limonene (13.65%), and α-fenchone (8.27%) in the fennel essential oil and linalool (28.63%), 1,8-cineole (18.65%), and 1-borneol (15.94%) in the lavender essential oil were found as main components. Contact and fumigant toxicity of essential oils was assessed against adult females of T urticae after 24 h exposure time. The essential oils revealed strong toxicity in both contact and fumigant bioassays and the activity dependeds on essential oil concentrations. Lethal concentration 50% for the population of mite ([LC.sub.50]) was found as 0.557% (0.445-0.716) and 0.792% (0.598-1.091) in the contact toxicity and 1.876 µL/L air (1.786-1.982) and 1.971 µL/L air (1.628-2.478) in the fumigant toxicity for fennel and lavender oils, respectively. Results indicated that F. vulgare and L. angustifolia essential oils might be useful for managing of two spotted spider mite, T. urticae.