In 1938, the bacterium Bacillus Popilliae (Bp) becomes the first microbial product registered by the U.S. government. It kills Japanese beetles. The first commercial insecticide based on Bt, Sporine, was produced in France in 1938 and used primarily to control flour moths.

Bacillus thuringiensis (Bt) is a unique bacterium in that it shares a common place with a number of chemical compounds which are used commercially to control insects important to agriculture and public health. Although other bacteria, including B. popilliae and B. sphaericus, are used as microbial insecticides, their spectrum of insecticidal activity is quite limited compared to Bt.