This research was conducted over 3 years in fields heavily infested with common scab (Streptomyces
scabies) in Victoria, Australia. It is widely thought that high soil pH is the main driver of increased common
scab expression. The four soil pH modifiers, hot lime, magnesium oxide, dolomite and gypsum, significantly
increased soil pH, but the effect on common scab development appeared to be seasonal i.e. in some seasons,
these amendments increased common scab, but in others they did not. Sulfur, which lowered soil pH, did not
consistently reduce common scab. Our results suggest that pH alone may not be a driver for the development
of common scab symptoms.