When a problem is found, the order is contain, diagnose, decide. Containment happens within the hour: cover the affected spot with damp paper so spores are not blown across the room; lift the bag or casing patch into a sealed bag and carry it out without passing over healthy beds; wash hands and tools; mark the rack in the diary.
Then close the routes: screens, filter, foot dip, who entered. Only when spread is stopped does the differential decide whether more is needed. Many outbreaks end at containment; a treatment applied while the source stays open is money spent at the wrong end. At crop end, NHB's cook-out of 70 °C for 12 hours contains the room itself.