Etude comparative de deux produits de neem (huile et poudre) sur les stades préimaginaux du moustique Culex quinquefasciatus(Diptera : Culicidae)

Comparative study of two neem products (oil and powder) on preimaginal stages of   Culex quinquefasciatus mosquito (Diptera: Culicidae) Neem ( Azadirachta indica ) products (neem oil formulated 1 % and neem powder 0.3 %), manufactured by a Senegalese industry (SENCHIM), were applied to mosquito ( Culex quinquefasciatus ) larvae and nymphs. The doses products were from 0.02 to 0.038 %  (neem oil) and 0.2 to 2 % (powder). In laboratory conditions, results showed that neem powder was more toxic at larval stage (mortalities between 86.1 and 100 %) than nymphal stage (between 14.5 and 95.9 % adults flow away). Neem oil formulated was effective as well as larval stage (mortality between 52.1 and 80 %) than nymphal stage (between 0 and 14 % adults flown away). The histopathological study  reveals that neem products act upon larval digestive system after ingestion, whereas for nymphs only contact effects are showed. Neem oil formulated 1 % appears more effective than neem powder 0.3 % for mosquitoes control in aquatic environment.