Larvicidal efficacy of Bacillus thuringiensis var israelensis and Bacillus sphaericus on Anopheles arabiensis in Ethiopia

The second instar larvae of the malaria vector mosquito, Anopheles arabiensis, were more susceptible to Bacillus thuringiensis var. israelensis (IPS-82) and B. sphaericus (SPH-88) than the third instar larvae. The LC(50) values were 1.0 mu g l(-1) and 1.8 mu g l(-1) for IPS-82 against second and third instar larvae respectively, after 48 h of exposure. The LC(50) values for SPH-88 were 3.6 mu g l(-1) against the second instar larvae and 7.6 mu g l(-1) against the third instar larvae of An, arabiensis. The larvicidal efficacy of SPH-88 was significantly less than IPS-82. The potential of IPS-82 for the control of An. arabiensis in malaria endemic areas is promising.