“Consider what happens after a diseased crop is watered; pools of contaminated water collect on the floor and some at least will dry out. Sooner or later someone will walk on the floor and disturb debris and Verticillium spores lying on it.
Air sampling showed that it only required one person to walk down the central gangway of a cropping house with a clean dry concrete floor for the dust and spore content of the atmosphere to increase noticeably”
Doreen G Gandy, GCRI
This type of spread can be prevented by sprinkling SPOREKILL on the floor.