Active monoterpene ketones isolated from Rosmarinus officinalis with fumigant and contact action against Tyrophagus putrescentiae (Schrank)

The acaricidal activities of an active material derived from Rosmarinus officinalis oil and its relative monoterpene ketones were determined using fumigant and contact toxicity bioassays against Tyrophagus putrescentiae and were compared with that of a commercial acaricide (benzyl benzoate). The active component of R. officinalis oil, isolated by silica gel column chromatography and high-performance liquid chromatography, was identified as camphor, based on various spectroscopic analyses. In the fumigant toxicity bioassay, camphor (2.25 μg/cm³) was 5.58 times more active than benzyl benzoate (12.56 μg/cm³) against T. putrescentiae, followed by (+)-camphor (3.89 μg/cm³) and (-)-camphor (5.61 μg/cm³). In the contact toxicity bioassay, camphor (1.34 mg/cm²) was 6.74 times more toxic than benzyl benzoate (9.03 μg/cm²) against T. putrescentiae, followed by (z)-camphor (2.23 μg/cm²) and (-)-camphor (2.94 μg/cm²). These results indicate that camphor and its derivatives are very useful as potential control agents against stored food mites regardless of the application method.