Irrigation regimes influenced pathogen populations in the soil. Low-level irrigations at R1 reduced F. virguiliforme pathogen populations in the soil when measured at mid-season compared to those at planting. Thus, there appears to be a negative relationship between disease severity and pathogen populations as influenced by irrigation. It is clear that there is a positive relationship between soil oxygen content and SDS disease severity, however there is no significant relationship between soil oxygen content and F. virguiliforme populations in the soil. Thus, this suggests that aerobic (higher oxygen) soils facilitate the SDS disease development process, as opposed to anaerobic (low oxygen) soils. So far, the data shows that irrigation treatments have an impact on soil pathogen populations as mentioned above. In general, it appears that low-level irrigations at R1 reduce F. virguliforme populations the most, however, after combining 2013 and 2014 data, the lowest disease severity was observed when low-level irrigations were conducted at V4 and high-level irrigations were conducted at R1.