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Research article2011Peer reviewed

Cordeauxia edulis and Rhododendron tomentosum extracts disturb orientation and feeding behavior of Hylobius abietis and Phyllodecta laticollis

Egigu, Meseret C.; Ibrahim, Mohamed A.; Yahya, Asha; Holopainen, Jarmo K.


The use of plant-based compounds to control insect pests is an alternative to the use of synthetic pesticides. We evaluated the repellent and antifeedant effects of Cordeauxia edulis Hemsley (Fabaceae) and Rhododendron tomentosum Harmaja (Ericaceae) extracts against Hylobius abietis L. (Coleoptera: Curculionidae) and Phyllodecta laticollis Suffrian (Coleoptera: Chrysomelidae). Repellent properties were evaluated by monitoring responses of adult insects toward the odor from extracts or extraction solvents (controls) in a Y-tube olfactometer, and choice or no-choice feeding tests were conducted by applying extracts or extraction solvents on stems of Scots pine [Pinus sylvestris L. (Pinaceae)] and European aspen [Populus tremula L. (Salicaceae)], host plants of H. abietis and P. laticollis, respectively. Extracts of R. tomentosum repelled adults of both insect species effectively. However, extracts of C. edulis did not repel H. abietis although its ethyl acetate extract showed repellence against the adults of P. laticollis. Feeding by H. abietis was significantly reduced by a methanol extract of C. edulis, and methanol and hexane extracts of R. tomentosum. Feeding by the adults and larvae of P. laticollis was significantly reduced by extracts from both plant species. Concomitant with less feeding, larval growth was retarded by ethyl acetate extracts of both plant species. Gas chromatography-mass spectrometry analyses of the volatile components of the extracts showed that extracts from both plant species were mixtures of various terpene and non-terpene compounds, which showed quantitative and/or qualitative variations between plant species and extraction solvents. This experiment showed that extracts from both plant species effectively manipulated the orientation and/or feeding behavior of the two beetle species. Hence, they may be considered as potential alternatives to synthetic chemical pesticides.


antifeedant; botanicals; deterrents; non-terpene compounds; repellent; terpene compounds; Y-tube tests; Coleoptera; Curculionidae; Chrysomelidae

Published in

Entomologia Experimentalis et Applicata
2011, Volume: 138, number: 2, pages: 162-174

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