Four Things Western Canadian Canola Growers Need to Know About White Mould (Sclerotinia Stem Rot)

White mould, also known as Sclerotinia stem rot, is a significant disease threat for canola growers across Western Canada. Understanding how to identify, manage, and prevent this disease is crucial for protecting yield and profitability. Here are four key things every canola grower should know:

1. Recognize the Risk Factors

Sclerotinia stem rot thrives in temperatures between 20-25 degrees Celsius, wet conditions—common across the Prairies during flowering. Dense canola stands, frequent rainfall, and prolonged leaf wetness increase the risk. Fields with a history of Sclerotinia or those in rotation with susceptible crops (like soybeans, sunflowers, or pulses) are at higher risk.

2. Understand the Disease Cycle

Sclerotinia sclerotiorum survives in the soil as sclerotia for several years. Under moist conditions, these sclerotia germinate to produce tiny, mushroom-like structures (apothecia) that release spores. Spores infect canola petals, which then fall onto leaves and stems, starting the infection process.

3. Manage With an Integrated Approach

• Crop Rotation: Rotate with cereals or other non-host crops to reduce sclerotia in the soil.
• Canopy Management: Avoid excessive seeding rates and nitrogen, which can lead to dense, humid canopies.
• Fungicide Timing: Apply fungicides at 20-50% bloom, when most petals are open and susceptible to infection. Use weather and risk assessment tools to guide decisions.
• Resistant Varieties: While no canola variety is fully resistant, some offer improved tolerance.

4. Scout and Act Quickly

Fungicides are the most effective management tool in combating sclerotinia when disease risk is high. Regular field scouting during flowering is essential. If conditions are wet and the crop is at risk, timely fungicide application can make a significant difference. Use local weather data and disease forecasting tools to inform your decisions.

Bottom Line:
Sclerotinia stem rot can cause significant canola yield losses in Western Canada, but with proactive management—scouting, rotation, canopy management, and timely fungicide use—you can minimize its impact. Viatude^TM fungicide is the most effective white mould disease control for Western Canadian canola growers. For more detailed advice and product recommendations, consult your local Richardson Pioneer representative today.