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

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Phlox > Spots on leaves

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  • Image: powdery mildew 1
  • Image: powdery mildew 2
  • Image: powdery mildew 3

Powdery Mildew
Erysiphe cichoracearum

  • Powdery, fluffy white spots and blothces 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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  • Image: fourline bug 1
  • Image: fourline bug 2
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Fourlined plant bug

  • Occurs May to early July
  • Feeding causes brownish or sunken spot on leaves
  • Nymphs are red or red and black; Adults are greenish yellow with 4 black stripes, 1/4 to 1/3 inch long
  • More information on Fourlined plant bug...
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  • Image: leaf spot 1
  • Image: leaf spot 2
  • Image: leaf spot 3

Leaf Spot
Ascochyta phlogis var. phlogina

  • Brown round to irregular spots with a purple border on leaves
  • Spots start out small, but can grow to kill large sections of the leaf
  • Spots typically start on lower leaves but can spread to cover the entire plant

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