Powdery mildew (PM) is caused by the fungus Erisyphe betae.

 

Identification

First signs are small white powdery patches on the upper surface of older leaves. Severely infected plants turn greyish-white. Leaves then yellow and eventually die.

 

Early powdery mildew infection on a sliver beet leaf.

 

Importance
Currently minor in fodder beet.

 

Spread
PM requires a living plant host to survive winter. During spring, wind-blown spores infect new leaves, plants and crops under dry, warm conditions.

 

Management
Infection under ideal conditions is relatively rapid, with control becoming less effective with time. Fungicides are available.