Neryl formate, (Z)-3, 7-dimethyl-2, 6-octadienylformate, was identified as the alarm pheromone of Rhizoglyphus setosus and Rhizoglyphus sp. 1. The compound was also confirmed as a major pheromone component of Rhizoglyphus sp. 2, in addition to neral [(Z)-3, 7-dimethyl-2, 6-octadienal], geranial [(E)-3, 7-dimethyl-2, 6-octadienal] and α-acaridial [2(E)-(4-methyl-3-pentenyl)-butanedial]. Although citral (a mixture of neral and geranial) was not always detectable in the 4 species including R. robini, all four Rhizoglyphus mites exhibited weak activity. On the other hand, α-acaridial only indicated the activity against Rhizoglyphus sp. 2. Neryl formate was found to be commonly distributed as the major alarm pheromone component in the four Rhizoglyphus mites, and therefore, it is concluded that the alarm pheromone was non-species-specific among these species.