African Violet Diseases

Informational table showing disease name, symptoms, pathogen/cause, and management of African Violet diseases.
African Violet Diseases - Articles

Updated: August 8, 2017

African Violet Diseases
DiseaseSymptomsPathogen/CauseManagement
Bacterial BlightDark reddish brown to black rotting areas form on roots and crown. Infected petioles have a greasy appearance.Erwinia chrysanthemiPot and propagate in pasteurized media. Do not take cuttings from infected plants. Avoid high temperature, high humidity conditions. Keep plants separate from new plants, especially foliage plants of unknown health.
Botrytis BlightSmall water-soaked lesions form on damaged petioles and spread to leaf blades. Infected flowers fade prematurely.Botrytis cinereaSpace plants and provide ventilation to avoid excessively high humidity. Remove fading flowers and yellowing leaves. Apply a fungicide to protect healthy tissue.
Foliar NematodeSmall tan, sunken areas form on lower surfaces of leaves. Spots become dry and dull black as they enlarge. Plants are stunted.Aphelenchoides ritzema-bosiDestroy infected plants. Water plants in a manner that keeps leaf surfaces dry and does not splash from plant to plant.
Phytophthora Crown RotCrowns and roots have a dark, water-soaked appearance. This spreads to petioles and leaf blades. Leaves remain firmly attached as the plant collapses.Phytophthora nicotianae, P. cryptogeaDo not propagate from infected plants. Pot in pasteurized media Destroy infected plants. Apply a fungicide to protect healthy tissue.
Powdery MildewWhite, mealy fungal growth on the leaves and flowers causes them to dry and die.Oidium Apply a fungicide to protect healthy tissue.
Pythium Root RotRoots are dark brown. Plants are wilted and yellowedPhythiumDo not propagate from infected plants. Pot in pasteurized media Keep hose end off the ground. Apply a fungicide to protect healthy tissue.
Rhizoctonia Crown RotPlants wilt, collapse, blacken, and die. A reddening of infected tissue may occur at soil line. Leaves readily detach from collapsing plants.RhizoctoniaDestroy infected plants. Pot in pasteurized media. Apply a fungicide to protect healthy tissue.
Ring SpotBright yellow or bleached ring patterns form on dark green leaves.Irrigation water mluch colder or warmer than the leaf surface causes cells to collapse.Keep irrigation water off the foliage. Use water that is at room temperature.


Phytophthora crown rot


Cold water spotting