The Australian cotton industry relies heavily on chemical pesticides for management of a diverse array of pest insects, weeds and diseases. Pesticide use is a major economic and environmental liability for the industry and all measures to reduce this dependence need to be taken. The bacterial pathogen of Helicoverpa, Bacillus thuringiensis (Bt) is one avenue for reducing the use of conventional chemicals. Bt produces a series of endotoxins which are highly specific for particular insect groups and is thus ideally suited as an environmentally friendly pest control agent. One Bt strain is toxic to Lepidoptera and is being increasingly used for Helicoverpa control in cotton. Many chemical companies are investing heavily to produce efficiacious, reliable and cost effective Bt products and their use is likely to increase dramatically over the next decade. Coincident with this change the industry will see the release of genetically engineered cotton varieties which have been transformed to produce the delta endotoxin from Bt, making them highly resistant to feeding by Helicoverpa larvae.