Casing is the main route by which wet bubble enters a farm. ICAR-DMR reports that its resting spores survive up to three years in casing soil, so soil carried over from an old crop is a standing risk.
Wet the material to 50 to 60 percent of its water holding capacity first, because dry soil does not carry heat. ICAR-DMR then steam pasteurises at 60 to 65 °C for 6 to 8 hours. Its wet bubble folder gives a shorter, hotter schedule of 54.4 °C for 15 minutes. Chemical drenching is also documented, and current label approval must be checked.