Bacterial stunt is a disease in which soil borne bacteria colonise cotton roots and inhibit the growth and mycorrhizal development of the plant. Brown discolouration develops rapidly in the roots of stunted plants. Stunting is relatively uniform and, therefore, may only be noticeable when parts of a field are affected and parts not. Stunting tends to be more severe in heavy clay soils, even though these soils may have high levels of nutrients such as phosphorus (Nehl et al 1996a, 1996b). In some cases crop growth picks up mid-season and yields are acceptable but yield loss of up to 50% occur when cotton is severely affected. There are few options for control of bacterial stunt. Eradication of the pathogenic bacteria from soil is impractical. Permanent bed systems appear to have lifted yields, although the relative patterns of stunting across fields remain. At present the best option for control is to optimise management of the crop