Acaricidal Activity of Laurus nobilis Oil and its Formulation on Spider Mite, Tetranychus urticae Koch and Two Predators, Typhlodromus negevi Swirski & Amitai and Phytoseiulus persimilis Athias-Henriot (Acari: Tetranychidae, Phytoseiidae).

Laurus nobilis L. essential oil (Bay Laurel) was extracted and chemical components of the oil were determined. LLinalool was the major compound (39.18%) of the extracted oil. Extracted oil was formulated (EC) as Laurcide. Extracted oil and Laurcide toxicity and repellency on Tetranychus urticae Koch were assessed. L. nobilis oil was more toxic to females by direct spray than fumigant, while a reverse effect was on eggs. LC50values were 1.02×104 and 2.1×104 ppm for females and 1.5×104 and 1.1×104 ppm for eggs by contact and fumigant, respectively. Laurcide proved to be more toxic than oil by direct spray and the eggs were more sensitive to formulation than females. LC50 values for eggs and females were 0.002 and 0.014%, respectively. Both tested material strongly repelled T. urticae females and deterring them from oviposition at all tested concentrations and at all exposure time periods. Laurcide shortened oviposition period and female longevity as well as reduced the number of deposited T. urticae eggs. The predatory mite, Typhlodromus negevi Swirski and Amitai and Phytoseiulus persimilis Athias- Henriot females were found to be more tolerant than T. urticae females to examined materials. The LC50 values reported to T. negevi and P. persimilis by oil were (1.82×104 and 2.00×104 ppm) and (0.28×104 and 0.40%×104 ppm) by formulation, respectively. On contrast, eggs of both predatory mite were not influenced. Laurcide resulted in reduction of reproduction and food consumption for T. negevi and P. persimilis as well as reduction in the female-biased sex ratios. The tested material considered safe on predatory mite when compared to control at the lethal concentration values reported to mite. Laurcide found to be non-persistent and its effect faded gradually after 2 days from spraying and the highest mortality was recorded as 40%. [ABSTRACT FROM AUTHOR]