International Journal of Tropical Insect Science

Cambridge Journals Online - CUP Full-Text Page

Research Article

Antifeedant activities of crude seed extracts of tropical African spices against Spodoptera littoralis (Lepidoptera: Noctuidae)


N.N. Ntonifora1, I. Mueller-Harveya2 c1, H.F. Van Emdena2 and R.H. Browna2



a1 Department of Life Sciences, University of Buea, PO Box 63, Buea, Cameroon

a2 Department of Agriculture, The University of Reading, PO Box 236, Reading, RG6 6AT, United Kingdom

Article author query

Ntonifor NN [PubMed]  [Google Scholar]
Mueller-Harvey I [PubMed]  [Google Scholar]
Van Emden HF [PubMed]  [Google Scholar]
Brown RH [PubMed]  [Google Scholar]

Abstract

The antifeedant activities of Piper guineense Schum et Thonn (Piperaceae), Aframomum melegueta (Rosk) K. Schum (Zingiberaceae), Aframomum citratum (Pareira) K. Schum (Zingiberaceae) and Afrostyrax kamerunensis Perkins and Gilg (Huaceae) seed extracts were investigated in laboratory dual- and no-choice bioassays using third-instar Spodoptera littoralis (Boisduval) larvae. In the dual-choice test, the hexane and methanol extracts of A. melegueta showed potent dose-dependent antifeedant activity at concentrations of ≥300 ppm and the water extract at ≥500 ppm, as illustrated by significantly lower leaf consumptions. Aframomum citratum methanol and water extracts exhibited antifeedant activity at ≥300 and ≥1000 ppm, respectively, but the hexane and ethanol extracts did not affect feeding at any concentration. Piper guineense ethanol and water extracts showed dose-dependent antifeedant effects at ≥300 and ≥500 ppm, respectively, and the methanol extract was active only at 1000 ppm. None of the extracts of the highly aromatic A. kamerunensis exhibited antifeedant activity at any of the tested concentrations. In the no-choice bioassays, extracts with antifeedant activity in the dual-choice tests also showed dose-dependent feeding inhibition. The hexane and methanol extracts of A. melegueta were effective in the no-choice tests at ≥100 and ≥500 ppm, respectively, and the water extract at ≥300 ppm. Similarly, the A. citratum water and methanol extracts were active at ≥500 ppm and the P. guineense water and ethanol extracts at ≥100 ppm. GC/MS chromatography of A. melegueta hexane and methanol extracts revealed volatile constituents with known anti-insect activity. The hexane and methanol extracts of A. melegueta, the methanol extract of A. citratum and the water and ethanol extracts of P. guineense may have potential for use by subsistence farmers.

(Accepted February 28 2006)

Key Words: Piper guineense; Aframomum melegueta; Aframomum citratum; Afrostyrax kamerunensis; seed extracts; botanical insecticide; Spodoptera littoralis

Correspondence:

c1 Email: i.mueller-harvey@reading.ac.uk


0Comments