African Journal of Biotechnology Vol. 5 (19), pp. 1846-1850, 2 October 2006   

ISSN 1684–5315 © 2006 Academic Journals        

Full Length Research Paper

Bioactive fractions of n-hexane extracts from Vigna pods against the legume pod borer, Maruca vitrata Fabricius

Oigiangbe, O.N.², L.E.N. Jackai², F.K. Ewete³ and L. Lajide⁴.

¹Insect Rearing Unit, International Institute of Tropical Agriculture, Ibadan, Nigeria.

²Campbell Hall, Room 200-B, Tuskegee University, Tuskegee, AL 6088, USA.

³Department of Crop Protection and Environmental Biology, University of Ibadan, Ibadan, Nigeria.

⁴Dept. of Chemistry, Federal University of Technology, Akure, Nigeria.

*Corresponding Author. E-mail: noigiangbe2001@yahoo.co.uk.  Tel: +2348035755679.

Accepted 8 August, 2006

The identification of resistance factors in Vigna species has been a major constraint to the development of effective host-plant resistance against the major insect pests of cowpea. We studied the effects of some fractions of the n-hexane extract of green pods of three Vigna species namely V. vexillata, V. oblongifolia and V. unguiculata on the growth, development and fecundity of Maruca vitrata Fabricius. When incorporated in the artificial diet, the phenolic, acidic and basic fractions had no significant effect on larval growth and development. However, the neutral fraction from the three Vigna species showed antibiosis by significantly reducing larval weight, percentage pupation and adult emergence. There was no pupation on diet with V. vexillata neutral fraction. We conclude that neutral fractions of the green pods of wild Vigna species contain metabolites which can be exploited in the genetic engineering of cultivated cowpea for resistance against M. vitrata.

Key words:     Vigna species, resistance, n-hexane extract, Maruca vitrata, larval growth, fecundity.