Bacillus thuringiensis (Bacillus thuringiensis, referred to as Bt) is currently the largest output, the most widely used biological insecticide. Its main active ingredient is one or more of insecticidal crystal proteins (insecticidal crystal proteins, ICPs), also known as the δ- toxins, Lepidoptera, Coleoptera, Diptera, Hymenoptera, Homoptera, etc. insect, and animal and plant nematodes, mites and other arthropods have specific cytotoxic activity, and therefore safe for non-target organisms, Bt insecticide has loyal, efficient and safe to humans and animals, such as Bacillus thuringiensis advantage of the current commercial preparations have been more than 100 kinds, is the world’s most widely used, the largest amount, the best microbial pesticides, thus much attention. However, in the production of goods Bt preparations Prevention also shows some limitations, such as fast-acting is poor, the elderly larvae insensitive, field engineering strain persistence short and restructuring and other genetic traits have become unstable affect the success of Bt further promote the use of constraints. Therefore, in order to improve the effect of Bt insecticidal formulations, study its efficiency pathway has become a worldwide research focus, including: screening efficiency strains; using chemical additives, plant it plain sense, as synergistic chitinase substance; interaction between the efficiency of insect pathogens, etc.
