Spike Lavender Essential Oil Reduces the Survival Rate and Fecundity of Two-spotted Spider Mite, Tetranychus urticae (Acari: Tetranychidae)

The two-spotted spider mite, Tetranychus urticae Koch, causes major yield loss in numerous plants. The control of this mite is achieved mainly with synthetic acaricides; other strategies are the use of predatory mites or plant natural products. This study evaluated the effects of Lavandula latifolia Medik. (Lamiaceae) essential oil on the survival rate and fecundity of T. urticae by slide-dip and leaf-disk bioassays. Acute contact toxicity was provoked by different spike lavender oil concentrations although 95-100% mortality was observed when emulsions contained at least 0.20% (v/v). In the residual toxicity experiments, lavender oil (0.15-0.25%) reduced mite survival and affected its fecundity; laid eggs and emerging larvae were lowered as the oil concentration increased. Incubation temperature determined egg viability; 12ºC did not allow larval development, while the highest percentage of hatched eggs was counted at 30ºC. Our results confirmed the possibility of using spike lavender oil as an alternative to conventional pesticides.