Field trials with Vectolex (Bacillus sphaericus) and Vectobac (Bacillus thuringiensis (H-14)) against Anopheles gambiae and Culex quinquefasciatus breeding in Zaire.

Under field conditions in Kinshasa, Zaire, an aqueous suspension of Bacillus thuringiensis (H-14), Vectobac (12-AS), lost most of its larvicidal activity at all concentrations after 48 h against Culex quinquefasciatus breeding in polluted gutter water and Anopheles gambiae breeding in clear water irrigation ponds. However, good control of Cx. quinquefasciatus was obtained using a granular formulation of B. sphaericus, Vectolex-G (ABG-6185), at concentrations of 10-30 kg/ha. High concentrations of Vectolex-G gave excellent control of An. gambiae breeding in irrigation ponds. The Vectobac-G was less active against An. gambiae than Vectolex-G, in spite of good dispersion of Vectobac-G particles.