STUDIES ON BACILLUS-THURINGIENSIS STRAINS ISOLATED FROM SWEDISH SOILS- INSECT TOXICITY AND PRODUCTION OF BACILLUS-CEREUS DIARRHEAL-TYPE ENTEROTOXIN

At moderate concentration, 23 of 40 strains of Bacillus thuringiensis isolated from Sweden were toxic to Trichoplusia ni and five were toxic to Aedes aegypti. Five of the strains were toxic to Diabrotica undeci mpunctata at high concentration, two were toxic to Heliothis virescens at low concentration and five produced thuringiensin (formerly called beta-exotoxin). No strain was toxic towards the beet armyworm Spodopt era exigua at low concentration. Twenty-three of the strains produced a B. cereus-diarrhoeal-type enterotoxin.