Insecticidal activity of monoterpenes against Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst)

Secondary metabolites play an important role in plant resistance to insects. The monocyclic monoterpenes 1,8-cineole (eucalyptol) and R-(+)-limonene have been considered economically important in this context. Cineole is a component of different species of Eucalyptus spp. and limonene is a constituent of Citrus spp. essential oils. These substances were bioassayed to determine possible fumigant, contact, and ingestion activity against Rhyzopertha dominica (F.), lesser grain borer, and Tribolium castaneum (Herbst), red flour beetle, which are important pests of stored grain. It was possible to show that both compounds are insecticidal against the two insects, mainly in the contact and/or ingestion action.