Action level, concentration level of airborne eto in or at breathing level. Which is 0.5 ppm
Always decontaminate equipment after working in a field suspected of having the club-root fungus by thorough washing followed by spraying all surfaces with a disinfectant such as Lysol, formaldehyde, etc. Grow cabbage and related crops once every three to five years with crops not in the mustard family.
It is best to rotate your cabbage crop every season due to its high absorption of nitrogen and potassium from the garden soil. This allows the soil time to replenish its nutrients. Do not plant cabbage or other members of the cabbage family in the same location in your garden more that once every 3-4 years. This will help prevent your plants from being infected with soil-born diseases that attack the cabbage family.