Clubroot, blackleg and sclerotinia stem rot are found in many canola fields at this stage of the season. Taking time now to determine what diseases are present and at what levels can help with variety decisions and crop rotation planning for next year.
While at random locations in the field checking for crop staging and seed colour change, also check for diseases. Note that while you may not see above ground symptoms, blackleg severity inside stems and clubroot development on roots may be at levels that will require management measures next year to prevent serious yield loss.
Here are links to videos that will help you understand these diseases and how to manage them.