The acaricidal activities of compounds derived from the oil of Pelargonium graveolens leaves against the storage food mite, Tyrophagus putrescentiae, were compared with the activity of a commercial acaricide, benzyl benzoate, in an impregnated fabric disk bioassay. Purification of the active constituent from P. graveolens was accomplished by silica gel chromatography and high-performance liquid chromatography. Structural analysis of the active constituent by 1H nuclear magnetic resonance (NMR), 13C-NMR, 1H-13C shift correlated spectroscopy NMR, and distortionless enhancement by polarization transfer NMR identified trans-3,7-dimethyl-2,6-octadien-1-ol (geraniol). Based on the 50% lethal dose values, the most toxic compounds against T. putrescentiae were geraniol (1.95 microg/cm3), which was followed by nerol (2.21 microg/cm3), citral (9.65 microg/cm3), benzyl benzoate (11.27 microg/cm3), and beta-citronellol (15.86 microg/cm3). Our results suggest that geraniol is more effective in controlling T. putrescentiae than benzyl benzoate is. Furthermore, geraniol, which is used as a flavoring for beverages, candies, ice creams, and baked goods and congeners (citral and nerol), may be useful for managing populations of T. putrescentiae.