Toxicity of Rosmarinus Officinalis Essential Oil to the Pest Tetranychus Urticae Koch (Acari: Tetranychidae) and its Predator Phytoseiulus Persimilis Athias-Henroit (Acari: Phytoseiidae)

Abstract

This study aims to determine the chemical composition of Rosmarinus officinalis (Lamiales: Lamiaceae) and its acaricidal effect on the pest mite Tetranychus urticae Koch (Acari: Tetranychidae). and its predator Phytoseiulus persimilis Athias-Henroit (Acari: Phytoseiidae). The analysis of the chemical composition of the essential oil extracted was carried out on gas chromatography coupled with mass spectrometry. Three major compounds found in the essential of R. officinalis were α-pinene (32.64%), β-Humulene (8.71%), and Camphene (5.95%). The toxicity of R. officinalis oil was performed using inhalation bioassay on both T. urticae and its predator P. persimilis. The results obtained showed high toxicity on the mite than to its predator with a mortality rate of 80% and 16.11% respectively at the dose of 4%. The fertility of females, the hatching of eggs, and the emergence of adults in T. urticae were also studied using contact bioassay where a total reduction of all three biological parameters was recorded at the dose of 4%. Besides, the application of this oil will also allow the conservation of P. persimilis. Altogether, the combination of toxicity on T. urticae and preservation of its predator gives R. officinalis essential oil a propitious potential for the control of the pest mite T. urticae and maintenance of environmental balance.