The effectiveness of benzyl benzoate and different chemicals as acaricides

Several observations have indicated that house-dust mites (HDM) play an important role in allergic diseases. Thus, the primary form of treatment should aim at reducing exposure to HDM for these patients. Allergen-avoidance measures in homes have been demonstrated to be beneficial in decreasing the risk of sensitization, severity of symptoms, bronchial reactivity, and basophil sensitivity. Various chemical methods, as well as physical measures, have been tried to eliminate mite allergens from house dust. However, none have gained wide acceptance because of the lack of effectiveness and safety, and the high cost. It is clear that new approaches are required for effective long-term control of HDM allergens. This study compared the acaricidal activities of phenyl salicylate, tea leaf extract (high tannic acid content), and essential oils (eucalyptus and laurel) with that of benzyl benzoate. The contact, short-duration persistence, and residual effects of various concentrations of these chemicals and benzyl benzoate were assessed in laboratory conditions with specially designed wells. Our data suggest that benzyl benzoate may not be effective when applied according to the manufacturer's instructions, but may be effective when applied more frequently (i.e., three to four times a year) and for longer periods (up to 24 h) even with lower concentrations (0.4%). Essential oils were shown to have little acaricidal activity, but virtually no effect was observed with tea. Among the chemicals used, phenyl salicylate seems to be promising as an alternative acaricide.