Coreopsis,Threadleaf
Symptom Cause  
Leaves curl/discolor; honeydew evident on leaves, sometimes sooty mold forms
Aphids
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Leaves mottled; distorted
Aster Leafhoppers
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Flowers discolored; deformed, leafhoppers present
Aster Yellows
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Crowns and roots rot
Crown Rot
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Leaves and stems eaten; plant gone
Deer
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Leaves mottled; flowers malformed
Mosaic Viruses
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Leaves coated white; spotted or blotched
Powdery Mildew
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Ragged holes in leaves, often in middle
Slugs and Snails
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Black powdery sooty mold fungus forms on honeydew
Sooty Mold
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Small holes chewed in leaves and flower petals
Spotted Cucumber Beetle
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