Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Snapdragon > Leaves discolored white, yellow or pale green
Snapdragon > Leaves > Leaves discolored white, yellow or pale green
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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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Two-spotted Spider Mites
Tetranychus urticae
- Active during summer, particularly abundant during hot, dry weather
- Pale stippling appears on the upper leaf surface
- Leaves are discolored off green to whitish, yellowish, or bronze
- Premature leaf drop can occur
- Visible webbing occurs on infected leaves when populations are high
- Adults are tiny (1/50th inch long) and oval, greenish or yellowish with a dark spot on either side of the body
- More information on Two-spotted Spider Mites
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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
