Black rootrot of cotton has been observed in 98 per cent of the farms regularly surveyed by NSW Agriculture in the Macquarie, Namoi, Gwydir and Macintyre valleys.

Black root rot is an intractable soil borne disease that threatens the sustainability of Australian cotton fanning.

Plants can utilise an array of biochemical mechanisms to protect themselves against viral, bacterial, fungal and nematode pathogens.

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.