Fumigant antitermitic activity of plant essential oils and components from Ajowan ( Trachyspermum ammi ), Allspice ( Pimenta dioica ), caraway ( Carum carvi ), dill ( Anethum graveolens ), Geranium ( Pelargonium graveolens ), and Litsea ( Litsea cubeba ) oils against Japanese termite ( Reticulitermes speratus Kolbe).

Plant essential oils from 26 plant species were tested for their insecticidal activities against the Japanese termite, Reticulitermes speratus Kolbe, using a fumigation bioassay. Responses varied with source, exposure time, and concentration. Among the essential oils tested, strong insecticidal activity was observed with the essential oils of ajowan ( Trachyspermum ammi ), allspice ( Pimenta dioica ), caraway ( Carum carvi ), dill ( Anethum graveolens ), geranium ( Pelargonium graveolens ), and litsea ( Litsea cubeba ). The composition of six essential oils was identified by using gas chromatography-mass spectrometry. The compounds thus identified were tested individually for their insecticidal activities against Japanese termites. Responses varied in a dose-dependent manner for each compound. Phenol compounds exhibited the strongest insecticidal activity among the test compounds; furthermore, alcohol and aldehyde groups were more toxic than hydrocarbons. The essential oils and compounds described herein merit further study as potential fumigants for termite control.