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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Zinnia > Leaves discolored brown to black

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Zinnia > Leaves > Leaves discolored brown to black

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  • White mold 1
  • White mold 2
  • White mold 3

White Mold
Sclerotinia sclerotiorum

  • Entire plant or single branch wilts, leaves turn brown and die
  • Wilted stems are discolored, tan to off-white, at the base near the soil line
  • Fluffy, white cotton-like fungal growth may been seen on infected plants when humidity is high
  • White to black hard spheres ranging in size from 1/16 to ½ inch can be found clinging to the outside an infected stem or embedded inside the dead stem
  • More information on white mold
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  • Root rot 1
  • Root rot 2

Root rot
Rhizoctonia solani and Pythium spp.

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  • Gray mold 1
  • Gray mold 2
  • Gray mold 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
  • Commonly on seedlings and young transplants
  • More information on gray mold
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  • Cold damage 1
  • Cold damage 2
  • Cold damage 3

Cold Damage

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