Acaricidal activity of 31 essential oils extracted from plants collected in Tunisia

The two-spotted spider mite Tetranychus urticae Koch is a worldwide pest, feeding on a large variety of plant families. As its resistance to acaricides spreads rapidly, it is crucial to develop new biological control tactics to manage its populations. In this respect, essential oils may be a good alternative, as they are currently considered minimum-risk pesticides. In this paper, we conducted a series of laboratory experiments to determine the susceptibility of adult females to 31 essential oils extracted from plants collected from Tunisia and compare it with the results obtained with two synthetic acaricides (spirodiclofen and fenbutatin oxide). Details of the essential oil yield of these plants were also recorded. A maximum yield of 0.5% was obtained. Laboratory bioassay indicated that the development of the tetranychid mite population was significantly affected by the use of Deverra scoparia, Haplophyllum tuberculatum, Chrysanthemum coronarium and Mentha pulegium plant extracts that killed 97%, 93%, 93% and 91% of T. urticae, respectively. The chemical composition of the most effective extracts were characterized by gas chromatography-mass spectrometry (GC-MS) and fast GC-flame ionization detector (FID). The evaluation of the potential of biologically active plant volatiles against T. urticae might provide a new approach to the development of natural acaricides to be used both in biological and integrated pest management strategies for controlling two-spotted spider mites.