Powdery Mildew of Brassicas

Erysiphe cruciferarum

Oidium species


Cream to white powdery spores and mould on the top of the older leaves.

In Canola, it tends to occur as a white powdery growth that turns black with time on the leaves, stem and pods fairly late in the season. It is most common in thick crops with high levels of nitrogen under humid conditions.

Species Affected:

Brassicas, Canola.

Brussels Sprouts, Cabbage and Swedes are more sensitive than other species.


More common in warm and dry conditions.

Survives on green tissue.

Spread by wind.

Life Cycle:

Origin and History:



Relatively common in Canola but rarely causes economic losses.

Management and Control:

Control rarely required.

Rainfall and overhead irrigation reduces the disease by washing spores off the leaves.

Related and Similar Species:




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