Roy spent plenty of time in the laboratory quantifying Fusarium oxysporum f. sp. vasinfectum (Fov) DNA from field soil, and some of his work is now reported in a Plant Disease publication: https://doi.org/10.1094/PDIS-08-21-1664-RE

The work’s objective was to describe spatial variability in Fov inoculum density in the field, because that variation is hypothesized to affect risk of cotton plants expressing Fusarium wilt disease. Much of Roy’s report concerns development of the quantification method, which targets the Fov race affecting the selected field sites. Roy discovered that inoculum density varies across the field space by orders of magnitude (shown in the figure below, where “inoculum level” is a relative logarithmic scale), and by observing it at multiple time points he noticed a temporal pattern: inoculum density trajectory depends on growth resource type and availability, which depends on prior inoculum density.  Roy is now finishing documentation of that cycle in this system.