HISTORY OF BACILLUS-THURINGIENSIS

Bacillus thuringiensis (Bt) was isolated from a flour moth collected i n the German province of Thuringia and described by Berliner in 1915. The same organism had already been described by Ishiwata in 1902 as Ba cillus sotto from Japan where it causes a wilt disease of silkworm cat erpillars, but the description was not known to Berliner. Bt is now th e accepted name for a range of aerobic spore-forming bacteria which fo rm an insect toxic crystal during sporulation. However, many bacteriol ogists consider Bt to be a variant of Bacillus cereus, a ubiquitous so il-inhabiting bacterium. Since the pioneering work of Steinhaus in Cal ifornia in the early 1950s, there has been considerable commercial int erest and products are now sold in most countries of the world for con trol of caterpillars (var. kurstaki, entomocidus, galleriae and aizawa i), mosquito and blackfly larvae (var. israelensis) and beetle larvae (var. tenebrionis and san diego).