Bt variety aizawai is used to control wax moth larvae in bee hives and various caterpillars. It is important for control of diamondback moth caterpillar which has developed resistance to Bt variety kurstaki in some areas. Check the label. Not only must the insect have the correct physiology and be at a susceptible stage of development, but the bacterium must be eaten in sufficient quantity. When ingested by a susceptible insect, the protein toxin damages the gut lining, leading to gut paralysis.
Affected insects stop feeding and die from the combined effects of starvation and tissue damage.
Bt spores do not usually spread to other insects or cause disease outbreaks on their own as occurs with many pathogens. Diagram courtesy of Abbott Laboratories . Bt genes have been transferred into other microorganisms to produce more active formulations, some of which are commercially available. Additionally, researchers have genetically engineered varieties of several plant species to express the Bt toxin as part of the plant's normal development. The evaluation and development of management systems for these new plant lines are the subject of considerable research.