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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Delphinium > Spots on leaves

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Delphinium > Spots on leaves

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  • Image: powdery mildew 1
  • Image: powdery mildew 2

Powdery Mildew
Erysiphe cichoracearum

  • Powdery, fluffy, white spots or blotches on leaves, stems and flower parts
  • Tiny raised black dots may be visible within white spots late summer or early fall
  • 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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  • Image: septorial leaf spot 1
  • Image: septorial leaf spot 2
  • Image: septorial leaf spot 3

Septoria Leaf Spot
Septoria delphinella

  • Irregular purplish black leaf spots, often with one side flat along a leaf vein
  • Mature leaf spots often have gray center
  • Long purplish black spots may be seen on stems
  • Leaf spots typically start on the lower leaves but can spread to the entire plant
  • Leaves with many appear completely black, dried up and tattered
  • In severe infections all of the leaves of the plant will appear black
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  • Image: southern blight 1
  • Image: southern blight 2
  • Image: southern blight 3

Southern Blight
Sclerotium rolfsii

  • Leaves turn yellow then brown from the edges inward and wilt
  • The base of the stem may be brown or discolored
  • Tiny tan to reddish brown hard spheres and white cottony growth can be seen at the base of infected leaves or in the soil around infected plants
  • Often seen after warm wet weather
  • More information on Southern Blight...

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