Responses of Tribolium castaneum (Coleoptera: Tenebrionidae) and Sitophilus oryzae (Coleoptera: Curculionidae) against essential oils and pure compounds
The essential oils of Zingiber officinale rhizomes (Zingiberaceae) and Piper cubeba berries (Piperaceae) as well as pure compounds, α-pinene and β-caryophyllene, were evaluated for their contact toxicity, persistence of insecticidal and antifeeding activities against T. castaneum and S. oryzae. β-Caryophyllene showed highest toxicity followed by P. cubeba, Z. officinale and α-pinene against both insects. S. oryzae was more sensitive than T. castaneum to both essential oils and pure compounds. α-pinene had least persistence followed in increasing order by β-caryophyllene while Z. officinale and P. cubeba essential oils showed same trends regarding persistence but more than pure compounds. In antifeedant assay, both essential oils and pure compounds exhibited antifeedant activities against T. castaneum and S. oryzae adults. Feeding deterrency was maximum in both insects by P. cubeba essential oil followed by Z. officinale essential oil, β-caryophyllene and α-pinene.