The Effective Insecticidal Activity of the two Extracts Ethyl Acetate and Hexan of Trichilia gilgiana against Sitophilus zeamaïs

Post-harvest losses are recognized to be one of the critical constraints upon food security among farmers of poor resource in Africa.The use of botanical pesticides in pest management during storage against insects is often encouraged because synthetic insecticides produce multiple side-effects on human health and environment. Insecticidal activity of the hexane, dichloromethane, ethyl acetate and methanol extracts of bark of Trichilia gilgiana was tested on Sitophilus zeamais, Tribolium castaneum and Rhyzopertha dominica. The mortality rate was measured variable. The results of analysis showed that the mortality rate has a very highly significant variation following extracts, doses, insects and time considered (P < 0.001). Extracts with ethyl acetate and hexane of Trichilia gilgiana are effective against S. zeamais at the highest doses (1 g/ 10 mL and 0.5 g/10 mL of solvent). These effective extracts were characterized by gas chromatography coupled with mass spectrometry. Molecules such as 2-Oxazalidone; thiocyanic acid; Methanethioamide, N,N-dimethyl; 2-Coumaranone and other were characterizated. These results may consolidate traditional use of Trichilia gilgiana in pest management.