ANTIFEEDANTS FROM CITRUS-NATSUDAIDAI HAYATA AGAINST TERMITE RETICULITERMES-SPERATUS KOLBE

The lower precipitated layer of a methanol extract of Citrus natsudaidai seeds, when applied to paper discs at a dosage ranging from 500 to 2000-mu-g/disc, significantly deterred feeding by Reticulitermes speratus nymphs. Three termite antifeedant limonoids (i.e., obacunone, nomilin and limonin) were identified as the active principles. Obacunone (with a minimum effective dosage of 150-mu-g/disc) was about two-fold more active than nomilin. Limonin was weak even at 1000-mu-g/disc.