African Journal of Agricultural Research Vol. 2(4), pp. 164-167, April, 2007

ISSN 1991- 637X­© 2007 Academic Journals

Full Length Research Paper

Chronic toxicity of essential oils of 3 local aromatic plants towards Sitophilus zeamais Motsch. (Coleoptera : Curculionidae)

Ngamo Tinkeu L. S.², Goudoum A.^1*, Ngassoum M. B.¹,  Mapongmetsem², Lognay G.³, Malaisse F.³ and Hance T.⁴

¹Ecole Nationale Supérieure des Sciences Agro-Industrielles, Université de Ngaoundéré; B.P: 455 Ngaoundéré (Cameroun).

²Faculté de Sciences: Département des Sciences Biologiques, Université de Ngaoundéré; B.P: 454 Ngaoundéré (Cameroun).

³Faculté Universitaire des Sciences Agronomiques; B.P: 5030 Gembloux (Belgique)

⁴Unité d'Ecologie et de Biogéographie; Place Croix du Sud, 4-5, B.P: 1348 Louvain-la-Neuve (Belgique).

*Corresponding author. E-mail: goudoumaugust@yahoo.fr

Accepted 8 March, 2007

The maize weevil, Sitophilus zeamais is a major stored grain pest currently controlled by chemical pesticides. This commonly used control method to prevent post-harvest losses leads to pollution of the environment and intoxication of consumers. Essential oils of aromatic plants are more considered as good control alternative tools. The amount of active volatile of essential oils present in granaries is almost as infra lethal doses. The present work aimed to analyse the chronic toxicity of low doses of essential oils of Annona senegalensis Pers. (Annonaceae), Hyptis spicigera L. (Lamiaceae) and Lippia rugosa L. (Verbenaceae). These plants are toxic to the pest at high doses. At the dose 2.5 x 10-2 ml/ml, they all reduced the oviposition of S. zeamais. Moreover L. rugosa and H. spicigera were the most active of the biological potential of S. zeamais reducing significantly its amount of grains attacked (F = 8.63**) and that of the rejected flour (F = 41.04***). This chronic toxicity therefore prevents grains from destruction.

Key words: Aromatic plants, chemical control, essential oils, feeding deterrence, Sitophilus zeamais, oviposition