African Journal of Biotechnology Vol. 6 (24), pp. 2846-2854, 17 December 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Toxic effects of neem products (Azadirachta indica A. Juss) on Aedes aegypti Linnaeus 1762 larvae

Raymond Demba Ndione^1*, Omar Faye³, Mady Ndiaye¹, Abdoulaye Dieye², and José Marie Afoutou³

¹Université Cheikh Anta Diop de Dakar, Faculté des Sciences et Techniques, Département de Biologie Animale, Laboratoire de Biologie de la Reproduction (L.B.R.), Unité d’Entomologie, de Rickettsiologie, de Bactériologie, et de Virologie (U.E.R.B.V.), Sénégal.

²Senchim, Groupe Industries Chimiques du Sénégal (Chemical Industry Group of Sénégal), Km 13 Route de Rufisque - BP 21236 Dakar - Sénégal.

³Université Cheikh Anta Diop de Dakar, Faculté de Médecine de Pharmacie et d’Odonto-Stomatologie, Laboratoire d’Histologie-Embryologie-Cytogénétique, Sénégal.

*Corresponding author. E-mail E-mail: raymondndione@yahoo.fr. Phone: (221) 542.77.84/825.02.02. Fax: (221) 824.63.18 / 825.25.29.

Abbreviations: LC, Lethal concentration; Sol, Solvesso; LT, lethal time; F.N.O., formulated neem oil; LT, lethal time ; N.P., neem powder.

Accepted 29 October, 2007

Treatment and comparative analysis of the properties of aqueous extracts of seed kernel of Azadirachta indica A. Juss (neem) was carried out on Aedes aegypti larvae. The aim of this work was to evaluate lethal effects of neem products (1% Suneem, formulated neem oil and neem powder) on A. aegypti larvae. Assays showed that A. indica was toxic to larvae of A. aegypti. For 1% Suneem, 1% formulated neem oil and neem powder, the lethal concentrations and lethal time at 50% (LC₅₀ and LT₅₀) for A. aegypti were 2 and 8 mg/l after 24 h and 3 mg/l after 120 h, respectively. Assays showed that Suneem and Formulated neem oil were more toxic to A. aegypti than Neem powder. Both products of the neem (A. indica, A. juss) have a remarkable influence on the development of A. aegypti larvae, causing an inhibition of nymphs and adults emergency. The Histopathological results revealed a serious damage on the epithelial columnar cells, a perturbation of alimentary flow, slightly hypertrophied cells, a beginning of vacuolisation on apical level, and a bursting of some cells in posterior part of the gut. However, nuclei, adipose tissue and muscles seem to keep normal appearance.

Key words: Azadirachta indica (neem), Aedes aegypti (mosquito), LC₅₀, emergency, histopathology.