Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Coleus > Discolored leaves
Coleus > Leaves > Discolored leaves
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Downy Mildew
Plasmopara lamii
- Large brown angular blotches may appear on leaves
- Leaves may curl slightly downward, downy white to fungal growth on underside of leaves
- Plants become yellow in color and stunted
- Infected leaves prematurely drop from the plant leaving a barren stalk with few leaves
- Cool, wet weather favors disease
- More information on Downey mildew
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Root Rot
Rhizoctonia solani, Phytophthora spp., and Pythium spp.
- Leaves wilt and turn yellow
- Plants are stunted
- The base of the stem may turn brown and crack
- Roots have brown sunken areas and lack root hairs
- Disease favors cool, wet soil with poor drainage
- Lab test necessary to distinguish between Rhizoctonia and Pythium Root Rot
- More information on Rhizoctonia root rot
- More information on Pythium root rot
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Sunscald
- Exposed parts of leaves bleach yellow to white
- In severe cases, affected areas turn brown and brittle
- Symptoms more severe in dry hot weather
- For more information on Sunscald
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Impatiens Necrotic Spot Virus (INSV)
- Symptoms are extremely variable
- Stunted growth and wilting may occur
- Leaf distortion; ringspots or black spots on leaves and stems; blackish/purplish coloration along leaf veins
- Tip dieback and in some cases entire plant will collapse
- Lab test needed to identify INSV since it is difficult to diagnose on symptoms alone
- For more information on INSV
