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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Geranium > Blotches or spots on leaves

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Geranium > Leaves > Blotches or spots on leaves

1 of 6
  • Bacterial leaf blight 1
  • Bacterial leaf blight 2
  • Bacterial leaf blight 3

Bacterial Leaf Blight
Xanthomonas hortorum pv. pelargonii
(syn. X. campestris pv. pelargonii)

  • Round water-soaked spots become tan to brown sunken spots, 1/8 to ¼ inch in diameter
  • Leaf spots grow into water-soaked, brown, V-shaped lesions with a yellow border.
  • Leaves wilt, turn yellow, than brown. May remain attached to the plant for a week or more
  • In severe cases, stems shrivel and turn brown or black
  • Common during periods of warm, moist weather
  • More information on Bacterial Leaf Blight
2 of 6
  • Gray mold leaf 1
  • Gray mold leaf 2
  • Gray mold flowers 3

Gray Mold
Botrytis cinerea

  • Brown spots on leaves with concentric brown rings like a bull’s eye
  • Leaf spots can expand to form large brown angular lesions and eventually blight the entire leaf
  • Brown blossoms or petals; flowers 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 6
  • Four-lined plant bug damage 1
  • Four-lined plant bug 2
  • Four-lined plant bugs 3

Four-Lined Plant Bug
Poecilocapsus lineatus

  • Present May to early July
  • Feeding causes brownish, round sunken spots on leaves
  • Nymphs are red or red and black; adults are greenish yellow with 4 black stripes, ¼ to 1/3 inch long
  • More information on Four-Lined Plant Bugs
4 of 6
  • Geranium rust 1
  • Geranium rust 2
  • Geranium rust 3

Rust
Puccinia pelargonii-zonalis

  • Pale green to yellow spots on upper surface of leaf
  • Reddish brown raised pustules form on the underside of the leaf
  • Pustules may develop an outer ring of reddish brown spores with age
  • Powdery reddish brown spores rub off when leaf spots are touched
  • Leaves eventually turn yellow and drop prematurely
  • More information on Geranium Rust
5 of 6
  • Oedema 1
  • Oedema 2

Oedema

  • Pale-green to white blisters or bumps on the undersides of leaves
  • Blisters may brown with age and have a crusty or corky appearance
  • Older leaves are more affected then younger ones
  • Occurs when plants are overwatered during cool or humid weather
  • More information on Oedema
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  • Plant virus 1
  • Plant virus 2

Viruses
Cucumber mosaic virus, Impatiens necrotic spot virus, Pelargonium flower break, and Tomato spotted wilt virus

  • Leaves may be mottled, deformed, discolored, or have yellow rings
  • Leaf veins may turn yellow
  • Flowers and leaves may be small or distorted
  • Plant may be stunted
  • Lab test needed to identify which virus is causing the problem
  • More information on viruses

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