ISSN 2326-7267
International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 2 (8), pp. 001-004, August, 2011. © International Scholars Journals
Full Length Research Paper
Contact toxicity of some fixed plant oils and stabilized natural pyrethrum extracts against adult maize weevils (Sitophilus zeamais Motschulsky)
H.N. Wanyika1, P.G. Kareru1*, J.M. Keriko1, A.N. Gachanja1, G.M. Kenji2 and N.J Mukiira3
1Department of Chemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
2Department of Food Science and Technology, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
3National Agricultural Laboratories, Kabete, Kenya.
Accepted 21 March, 2011
Abstract
The contact toxicity of some selected fixed plant oils and stabilized natural pyrethrum (Chrysanthemum cinerariaefolium) blends against adult maize weevils (Sitophilus zeamais) were investigated. Natural pyrethrum extract was stabilized against ultraviolet (UV) light by blending with fixed oils extracted from Azadirachta indica A. Juss (neem tree), Thevetia peruviana (yellow oleander) and Gossypium hirsutum L. (cotton) seeds. Cottonseed oil had the highest stabilization effect on the pyrethrum blend exposed to UV light of 366 nm. The results indicated that the natural pyrethrum extract blended with cottonseed oil was the most potent against maize weevils and that the potency was concentration-time dependent. Cottonseed and neem seed oils enhanced the stabilization of the natural pyrethrum insecticide.
Key words: Contact toxicity, maize weevils, ultraviolet light, natural pyrethrum, cottonseed oil.