Coreopsis Diseases

Informational table showing disease name, symptoms, pathogen/cause, and management of Coreopsis diseases.
Coreopsis Diseases - Articles
Coreopsis Diseases
DiseaseSymptomsPathogen/CauseManagement
Aster yellowsFlowers develop green, elongate, or stunted petals and an excessive number of flower heads. The affected plants are usually stunted and yellowed.PhytoplasmaMaintain good leafhopper control and eliminate nearby weeds that harbor aster yellows.
Bacterial leaf spotIrregular brown blotches and spots develop on leaves.Pseudomonas cichoriiWater in a manner that keeps leaf surfaces dry and water when the leaves will dry quickly. Remove infected plants. Apply a bactericide to protect plants.
Botrytis blightLower leaves die and become covered with white to gray, fluffy fungal growth that soon becomes a mass of gray spores.Botrytis cinereaWater in a manner that keeps leaf surfaces and flowers dry and water when the plants will dry quickly. Apply a fungicide to protect plants.
Crown rotPlants wilt, brown, and die. White fungal growth webs at the base of the dying plant and become peppered with small, tan, round structures.Sclerotium rolfsiiRemove infected plants. Mulch in a manner that does not hold moisture close to the stems.
Downy mildewBlack spots form on the upper leaf surface and white felt-like growth covers the underside of the leaf.Plasmopara halstediiApply a fungicide to protect plants.
Fungal leaf spotsPurple to tan spots develop on leaves.Cercospora, Septoria, PhyllostictaWater in a manner that keeps leaf surfaces dry and water when the leaves will dry quickly. Apply a fungicide to protect plants.
Powdery mildewWhite fuzzy growth develops on the upper side of the leaves.Sphaerotheca macularisApply a fungicide to protect plants.
Root rotPlants yellow, wilt, collapse, and die.Phymatotrichopsis or RhizoctoniaApply a fungicide to protect plants.
RustOrange-yellow masses of spores form on the underside of leaves.Coleosporium inconspicuumApply a fungicide to protect plants.
ScabLeaves have a coating of gray to brown spores.Cladosporium coreopsidisWater in a manner that keeps leaf surfaces dry and water when the leaves will dry quickly. Apply a fungicide to protect plants.
Stem rotStems turn brown or tan and die as large portions of the plant collapse.Alternaria sp., Rhizoctonia solani and Sclerotinia sclerotiorumRemove infected plants. Cut plants back to the soil line in the fall. Mulch in a manner that does not hold moisture close to the stems. Apply a fungicide to protect plants.
WiltPlants wilt, turn brown and die.Verticillium albo-atrumRemove infected plants. This fungus survives in the soil for very long periods of time, even in the absence of susceptible plants. Do not plant susceptible varieties.