[Isolation of a spore fraction of Bacillus sphaericus toxic for larvae of Anopheles].

A lethal fraction for Anopheles stephensi larvae has been isolated from Bacillus sphaericus strain 1593 spores by various methods The best results have been obtained by freezing and thawing which give an extract made in majority of protein with high molecular weight and causing 100% of mortality in 24 hours. Because of its easy extracction and its lack of diaminopimelic acid, the toxic fraction is thought to be located outside the spore coats.