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Impatiens Diseases

Informational table showing disease name, symptoms, pathogen/cause, and management of Impatiens diseases.
Disease Symptoms Pathogen/Cause Management
Alternaria Leaf Spot Brown spots and rings form on infected leaves. Alternaria Reduce humidity and maintain good air circulation. Space plants for good air circulation. Apply a fungicide registered for use on impatiens.
Botrytis Blight Flowers are spotted and stems rot. Botrytis cinerea Reduce humidity and maintain good air circulation. Do not space plants too closely. Remove fading flowers and yellowing leaves. Apply a fungicide registered for use on impatiens.
Bacterial Fasciation Plants stunted and have many short shoots at the crown. Corynebacterium fascians Discard infected plants. Do not propagate from infected plants. Propagate and plant in pasteurized potting media.
Damping-off Stems at the soil line die and plants collapse. Pythium or Rhizoctonia Plant in pasteurized potting media. Keep hose ends off the ground.
Powdery Mildew (New Guinea impatiens) White, mealy fungal growth develops on the top of leaves. Sometimes, heavy gray growth develops. Oidium Apply a fungicide registered for use on impatiens.
Pythium Root Rot Lower leave wilt, leaves fall, and the plant dies. Pythium spp. Pot in pasteurized, pathogen-free media. Keep hose ends off the ground. Apply a fungicide registered for use on impatiens.
Thielaviopsis Root Rot Roots become dark brown and rot. Lower stems have sunken lesions when infected. Thielaviopsis basicola Pot in pasteurized, pathogen-free media. Keep hose ends off the ground. Apply a fungicide registered for use on impatiens.
Verticillium Wilt Lower leaves yellow and fall. Infected plants may recover. Verticillium dahliae Pot in pasteurized, pathogen-free media. Do not take cuttings infected plants.
Virus Ring spots on leaves. Death of growing tips. Severe stunting. Impatiens necrotic spot virus Discard infected plants. Control thrips that carry the virus. Do not propagate from infected plants.

Alternaria leaf spot
Alternaria leaf spot.

Powdery mildew
Powdery mildew

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Impatiens necrotic spot virus symptoms
Impatiens necrotic spot virus symptoms.

Prepared by Gary W. Moorman, Professor of Plant Pathology

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Impatiens Diseases

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