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