PRESENT USE OF, AND PROBLEMS WITH, BACILLUS-THURINGIENSIS IN AUSTRALIA (CORRECTED VERSION OF NT932)

Bacillus thuringiensis (Bt) based products have an important role in t he management of insecticide resistance, the avoidance of problems ind uced by the destruction of natural biocontrol, and the reduction of th e chemical pesticide load in the environment. An estimated 100 000 ha of early-stage cotton were treated with Bt in 1990, usually in combina tion with endosulfan or thiodicarb at reduced rates. A further 10 000- 20 000 ha of other crops, mainly vines, pome fruits and cole crops, we re also treated. Occasional problems have resulted from the limited mo de of action and low persistence on crops demonstrated by Bt, and a pr icing structure that encouraged its use at marginally effective rates.