Soil-borne pathogens of potato cause a number of serious blemish diseases. By employing appropriate soil sampling strategies in conjunction with a method for soil DNA extraction and real-time PCR assays to detect and quantify target pathogens, we can validate the relationship between soil-borne inoculum and disease risk. The relationship between pathogen detection and disease risk for black dot (Lees et al. 2010 and Brierley et al. 2015) and powdery scab (Brierley et al. 2012) have been determined. Furthermore, the impact of soil-borne inoculum on disease has been investigated in conjunction with other control factors such as host resistance and crop management, for example, crop duration and chemical control (Brierley et al. 2018).