Integrated Strategies Protect Canola from Blackleg and Maintain Yield
Keeping canola crops market-ready requires vigilant blackleg management. Blackleg, a disease that affects canola, can cause significant yield and quality losses, impacting profitability and creating market risks says Keep it Clean.
To combat this, Keep it Clean is encouraging Canadian canola growers to adopt an integrated blackleg management strategy, which includes pre-harvest scouting, crop rotation, and using resistant varieties.
Blackleg symptoms appear throughout the growing season, but the best time to scout for the disease is just before swathing or when approximately 60% of the seeds have changed colour.
Effective scouting involves pulling up at least 50 plants in a W-pattern across the field. By clipping at the base of the stem or top of the root, growers can check for blackened tissue.
The severity of the disease can be rated on a scale from 0 (no discoloration) to 5 (completely discoloured). Each step on this scale correlates with a reduction in yield. Samples can be sent to testing labs to identify the blackleg races present in the field.
An integrated blackleg management strategy includes several essential practices.
Since the blackleg pathogen overwinters on infected residue, maintaining a break of at least two years between canola crops allows crop residue to decompose, reducing the pathogen’s presence. Regular scouting helps determine the effectiveness of the blackleg management plan.
Choosing canola varieties with blackleg resistance is crucial. Growers should select varieties rated as resistant (R) and rotate them to bring a mix of resistance genes to the field over time.
A blackleg race identification test can help match the appropriate resistance genes to the predominant races in the field.
Fungicide options also play a role in blackleg management. Enhanced seed treatments can protect seedlings from early infection, while early season foliar fungicide applications can prevent yield losses in higher-risk situations.
During non-canola years, controlling volunteer canola and other Brassica weeds such as stinkweed, shepherd’s purse, wild mustard, and flixweed is essential to prevent the build-up of the blackleg pathogen in the field.
By following these integrated management practices, canola growers can protect their crops from blackleg, ensuring market readiness and maintaining profitability.
Maintaining a healthy and productive canola crop requires dedication and informed management practices. Through regular scouting, crop rotation, and the use of resistant varieties, growers can effectively combat blacklegs and safeguard their yields.