How to Combat Blackleg and Protect Canola
Blackleg is a significant disease for Canadian canola growers, impacting both yield and quality, which can affect profitability and marketability. To control the disease and preserve genetic resistance in canola varieties, an integrated blackleg management approach is recommended says Keep It Clean. Pre-harvest scouting plays a critical role in identifying disease symptoms early, helping growers take timely action.
Although blackleg symptoms can be observed throughout the growing season, the ideal time for scouting is just before swathing or when about 60% of the seeds have changed color. At this stage, the disease is easier to identify, allowing growers to assess the extent of the problem.
To scout for blackleg, pull up at least 50 plants in a W-pattern across the field. Clip the base of the stem or top of the root to check for blackened tissue. Any discoloration can be compared to a severity scale, ranging from 0 (no discoloration) to 5 (completely discolored). The severity rating is directly linked to the potential yield loss; the more discoloration, the greater the impact on yield.
For further analysis, stem piece samples can be sent to testing labs to determine the specific blackleg races present in the field, helping tailor management strategies.