Canola Grey Stem

The Grey Stem disease is widespread throughout western Canada. The disease causes grey silvery or purplish patches to develop on the stem which can cover whole stems and continue to spread in stubble as plants decompose. Grey Stem usually infects too late to cause significant yield loss. 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, a characteristic of Blackleg not grey stem.

What To Look For

Grey Stem Grey Stem versus Blackleg


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
  • Reduce stress from competition by using good fertility practices