Effet d'extraits de plantes sur la bruche du niébé ("Callosobruchus maculatus" Fab.) et le charançon du riz ("Sitophilus oryzae" L.)

Résumé

To reduce storage losses in developing countries, protecting seeds by natural substances, which may be less toxic and less expensive than synthetic, may prove a worthwhile alternative. The present paper describes the results of laboratory testing of the effects of ester extracts of nine different plants against the cowpea weevil (Callosobruchus maculatus Fab.) and the rice weevil (Sitophilus oryzae L). Seeds were coated with ester extracts at three doses : 0.2, 0.5 and 1% w/w. In the cowpea weevil, the LD50 was exceeded after 24 hours with Ocimum basilicum 1% and Piper guineense 0.2%, and after 48 hours with Eucalyptus citriodora 1%, Capsicum frutescens 1% and Tetrapleura tetraptera 1%. In the rice weevil, the LD50 was exceeded after 24 hours with O. basilicum 1%, C. frutescens 1%, P. guineense 0.2% and T. tetraptera 1%, and after 48 hours with Eichhornia crassipes 1%.