| Abstract: | Five media, formulated from dried cow blood, mineral salts, and seeds from four species of legumes, were assessed for growth, sporulation, and insecticidal properties of Bacillus sphaericus strain 1593. Bacterial powders, prepared from broth, were assayed against Culex quinquefasciatus, Anopheles gambiae, and Aedes aegypti. Good growth and sporulation were obtained with all the media. The highest number of viable cells and spores per mililitre (8.6 X 10(8) and 8.1 X 10(8] were obtained in media containing ground seeds of Vignia unguiculata, Voandzeia subterranean, and Arachis hypogea. All powders were effective against C. quinquefasciatus and A. gambiae. Powders from media containing Arachis hypogea were the most effective with LC50's of 4.344 X 10(-3) +/- 1.650 X 10(-4) and 0.193 +/- 1.376 X 10(-2) micrograms/mL for C. quinquefasciatus and A. gambiae, respectively. Aedes aegypti larvae were only slightly susceptible to the powders. This investigation shows that these media can be used for the production of B. sphaericus 1593 primary powder. |
