CANOLA QUIZ – Clubroot scouting

Seeing galls again? Or seeing galls for the first time? Here are four quick questions to guide your pre-harvest clubroot assessment for 2021.

Clubroot galls
1. Clubroot infection could be lower in dry soil conditions. One reason is that resting spores need moist soils to germinate into infecting zoospores. What is the other reason?
2. Mud on equipment is a quick way to spread clubroot-infested soil. In dry conditions, what is the more likely way to spread clubroot-infested soil?
3. Biosecurity is important for farmers, agronomists and anyone accessing farm land. Disinfecting boots and scouting tools is a good step after each field visit. Select which two products are known to destroy P. brassicae resting spores when saturated for 10 minutes. (0.5 point each)
4. Lime will increase soil pH, making the soil less hospitable to clubroot. It can take a few tonnes per acre of lime to make a difference, so liming is probably most cost effective for patch management. What is the target soil pH when applying lime to manage clubroot?


Pre-harvest is a good time to scout canola for yield-limiting levels of disease. This is when disease symptoms tend to be most obvious, which makes it easy to assess the degree of damage. Please read Disease ID tips for pre-harvest scouting.