How to Manage Pests

Pests in Gardens and Landscapes

Pest identification and confirmation—Downy mildew

Downy mildew and powdery mildew may sometimes be confused. Here are some differing characteristics of the two.

Charateristic Downy mildew Powdery mildew
Favorable conditions
Cool, wet
Warm, dry
Location of white spores on leaves
Undersides
Both sides of leaves
Occurence of spores
Only after rain or irrigation
Abundant even in absence of water
Shape of discolored splotches
Bordered by veins; jagged
Circular
Under hand lens
Spores on branched stalks
Spores in chains
Spores of downy mildew
Spores of downy mildew
Spores of powdery mildew
Spores of powdery mildew

Statewide IPM Program, Agriculture and Natural Resources, University of California
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