What is Bt?

Bacillus thuringiensis (Bt) is a spore forming (flash animation) bacterium that produces crystals protein (cry proteins), which are toxic to many species of insects.

Where is Bt found?

Bt can be found almost everywhere in the world. Surveys have indicated that Bt is distributed in the soil sparsely but frequently worldwide. Bt has been found in all types of terrain, including beaches, desert, and tundra habitats.

How many kinds of Bt are there?

There are thousands of different Bt strains, producing over 200 cry proteins that are active against an extensive range of insects and some other invertebrates.

What type of bacteria is Bt?

Bt belongs to the family of bacteria, Bacillus cerus (B. cerus). B. cerus strains produce toxins that cause gastroenteritis (food poisoning) in humans. Bt is differentiated from B. cerus because it contains a plasmid (flash animation) that produces the protein crystals that are toxic to insects. Bt does not cause food poisoning.

Where is Bt used?

Bt is largely used in agriculture, especially organic farming. Bt is also used in urban aerial spraying programs, and in transgenic crops. To learn more about each of these topics, click on the corresponding link on the left.