Grey Stem disease is widespread throughout western Canada. Grey Stem will generally infect too late in the growing season to cause significant yield loss.
How do I Know if its Blackleg or Grey Stem?
To differentiate Blackleg and Grey Stem at the end of the season, cut the lower stem and look for dead blackened tissue in the crown. This blackened tissue is characteristic of Blackleg, not Grey Stem.
What to Look For
Grey Stem causes grey, silvery or purplish patches to develop on the stem of canola. These patches can cover whole stems and continue to spread into stubble as the plant decomposes.
Grey Stem Grey Stem versus Blackleg
Prevention
There are many measures you can take to prevent the spread of Grey Stem:
- Practice proper rotation of canola crops;
- Control all cruciferous weeds including volunteer canola; and
- Reduce stress from competition by using good fertility practices.