Many canola fields have seen heavy rainfall in recent weeks.
Some are starting to show signs of water damage in the form of yellow to brown discoloration.
Under extreme water pressure, canola plants will bolt and attempt to flower.
There are also reports of purpling of leaf margins and stems. This could be a symptom of water stress or a lack of consistent growing conditions. However, these symptoms also mimic sulfur deficiency.
If the grower has followed a 7:1 or 5:1 nitrogen to sulfur ratio in a spring fertilizer program, it is recommended to wait for better growing conditions to return and re-evaluate then for sulfur deficiencies.
If the purpling and cupping of the leaves continues, a rescue treatment of sulfur can be applied up to the bolting stage.
