Growers considering tillage for fall weed control should clean equipment between fields to limit disease (and weed seed) spread. Tillage equipment carrying soil and stubble from field to field can also carry soil- and stubble-borne diseases such as clubroot and blackleg.
In the case of clubroot, 99% of spores can be removed by physically removing any mud or soil from tires, openers, etc. Pressure washing and a rinse with bleach or other industrial cleaning solution can remove most of the rest.
Visit clubroot.ca for more on equipment sanitation and other prevention measures.