USE OF BACILLUS-THURINGIENSIS IN INTEGRATED CONTROL, ESPECIALLY ON COTTON PESTS

The resurgence of interest in Bacillus thuringiesis (Bt) in the Australian cotton industry is discussed principally in relation to increasing resistance problems and heightened environmentalism. The use of Bt in the cotton industry has been strategically targeted to two key areas: early season mixtures with below recommended rates of endosulfan (to reduce environmental contamination) and mid-season mixtures with pyrethroids (for resistance management). The current relatively high price of Bt (compared with conventional synthetic alternatives) is seen as a major constraint to the wider adoption of effective rates of Bt. Two incentive schemes, aimed at encouraging greater use of Bt, lowering the cost through economies of scale and engendering interest in a local fermentation facility, are discussed. The potential market for Bt in Australian cotton is assessed conservatively at 2 and possibly up to 5 million 1 annually. The resistance risk of this extensive usage is discussed, particularly in relation to its potential interaction with the possible misuse of transgenic cotton expressing Bt toxin(s). The requirements for the design of a 'perfect' Bt for cotton are discussed.