Key Points:
- White blister (also known as white rust) is not a true rust and is not well controlled by rust fungicides.
- It belongs to a group of organisms that includes the downy mildews and potato late blight. White blister spread is favoured by cool, damp conditions including heavy dews and irrigation, especially if applied late in the day.
- The disease is hard to control, especially if it becomes systemic within the plant.
- The importance of this seedborne inoculum in subsequent crop infection is not well understood and is currently being studied.
- White blister has a moderate to high risk of developing resistance to fungicides.
- Cultural controls such as paddock selection, removal of host weed species and good plant nutrition may reduce the risk of infection.
- Fungicide trials being conducted this season are focused on fungicides used for potato blight control.
- Last year with three applications starting at flowering Ridomil Gold MZ WG 3.0 kg/ha, Seguris Flexi + Comet (0.8 + 0.2 l/ha) and Pristine 400 g/ha gave the best seed yields in radish.