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

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Petunia > Leaves > Spots or blotches on leaves

1 of 3
  • Powdery mildew 1
  • Powdery mildew 2
  • Powdery mildew 3

Powdery Mildew
Oidium sp.

  • Powdery, fluffy white spots or 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
2 of 3
  • Gray mold 1
  • Gray mold 2
  • Gray mold on flowers 3

Gray Mold
Botrytis cinerea

  • Large brown spots or blotches on leaves
  • Leaves or entire plant may be completely blighted, brown, and wilted
  • Blossoms or petals may turn brown and drop off prematurely
  • Gray fuzzy mold develops on rotted tissue under humid conditions
  • Disease develops during cool, wet weather
  • More information on Gray Mold
3 of 3
  • Impatiens necrotic spot virus 1
  • Impatiens necrotic spot virus 2
  • Tomato spotted wilt virus

Impatiens Necrotic Spot Virus (INSV) or Tomato Spotted Wilt Virus (TSWV)

  • Symptoms may vary depending on cultivar, age of plant and other factors
  • Brown to black ring spots or flecks on leaves
  • Plants may be stunted and have distorted leaves
  • Severely infected young plants may turn brown and die
  • Lab test needed to identify which virus is causing the problem
  • More information on INSV and TSWV

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