Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Snapdragon > Spots or blotches on leaves
Snapdragon > Leaves > Spots or blotches on leaves
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Powdery Mildew
Oidium sp.
- Powdery, fluffy white spots and blotches on leaves, stems, and flower parts
- Tiny black round spheres may be visible within white spots late in the season
- Spots typically start on lower leaves but can spread to cover the entire plant
- Severely infected leaves may be completely covered in white or grayish white fungi
- In some cases, leaves become curled or twisted or turn yellow due to the infection
- More information on Powdery Mildew
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Snapdragon Rust
Puccinia antirrhini
- Yellow spots or blotches can be seen on the upper surface of infected leaves
- Raised brown pustules form on lower leaf surface primarily and grow in concentric rings with age
- Powdery reddish brown spores rub off on hands and tools
- Severely infected leaves wilt and die
- Plants can be stunted and may fail to bloom
- Disease develops during cool (below 60°F) weather
- More information on Snapdragon Rust
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Gray Mold
Botrytis cinerea
- Brown spots or blotches on leaves or stems
- Brown spots or blotches on flowers; flowers drop off prematurely
- As disease progresses, entire leaves, flowers and shoots turn brown
- Gray fuzzy mold develops on rotted tissue under humid conditions
- Disease develops during cool, wet weather
- More information on Gray Mold
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Downy Mildew
Pernospora antirrhini
- Leaves turn pale green to yellow and may curl slightly downward
- Downy white fungal growth on underside of leaves
- Plants become yellow in color and stunted
- Infected leaves prematurely drop from the plant leaving a barren stalk with few leaves
- Disease favors cool, wet weather
- More information on Downy Mildew
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Edema
- Pale-green to white blisters or bumps on the undersides of leaves
- Blisters brown with age and have a crusty or corky appearance
- Older leaves are more affected than younger ones
- Occurs when plants are overwatered during cool or humid weather
- More information on edema
