Contact toxicity and repellent activity of essential oils from Alpinia zerumbet cv. ‘Variegata’ against stored product insects

Alpinia zerumbet cv. ’Variegata’, as a special spice, has attracted social attention for its potential to replace synthetic chemicals as insecticides and repellents in food protection. In this work, the essential oils (EOs) from different organs of Alpinia zerumbet cv. ’Variegata’ (stem and leaf, flower, and rhizome) were extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). The contact toxicities and repellent activities of the extracted EOs, along with their common components, against three insect species (Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila) were evaluated. GC-MS analysis identified 25 components, and eucalyptol and camphor were the common primary components in the three EOs. The result showed that EOs and the main components (eucalyptol and camphor) exhibited varying degrees of contact toxicity and repellent activity against three insect species. Camphor exhibited more obvious contact toxicity than eucalyptol against both insect species (L. serricorne and L. bostrychophila), but the toxic effect was opposite for T. castaneum. The gray relation analysis explained that REOA had the strongest repellency against L. serricorne, with a coefficient of 0.52. The results in this study suggest that EOs of A. zerumbet cv. ’Variegata’ have the potential to be developed into botanical insecticides and repellents to control stored-product insects.