Begonia Diseases

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

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DiseaseSymptomsPathogen/CauseManagement
Bacterial Leaf Spot and BlightWater-soaked areas surrounded by yellow halos develop on leaves. Plants slowly die one leaf at a time.Xanthomonas campestris pv. begoniaePurchase plants free of the disease. Discard infected plants; particularly Rieger-types which are systemically infected. Remove infected leaves from Rex and tuberous types because they are not systemically infected. Do not wet leaves when irrigating. Do not propagate from infected plants. Destroy crop debris.
Botrytis BlightCuttings rot at their base. Tan spots develop on leaves. Established plants rot at the crown. Infected tissue is covered with dusty gray fungal growth.Botrytis cinereaMaintain low humidity by spacing plants and venting to improve air circulation. Remove dead and dying flowers and leaves. Apply a fungicide to protect plants.
Foliar Nematode"Plants are stunted. Excessive red pigment develops in infected leaves. Bronzed or water-soaked areas develop on leaves of some cultivars. Fibrous rooted cultivars have small brown leaf spots.Some cultivars exhibit no symptoms despite heavy infection.Aphelenchoides fragariaePurchase nematode-free plants. Avoid overhead irrigation and splashing. Discard infected plants.
Powdery MildewWhite, mealy fungal growth develops on leaves, flowers, and stems. Tissue beneath the fungus may die.OidiumExamine plants carefully and frequently to detect the onset of disease. Maintain a fungicide program to protect plants. Apply a fungicide to protect plants.
Pythium RotSeedlings die. Shiny blackened areas develop on the stems and petioles of established on the stems and petioles of established plants at and just above the soil line as plants collapse and die.PythiumPlant in pasteurized potting media. Keep hose ends off the ground. Do not overwater. Apply a fungicide to protect plants.
Rhizoctonia Crown Rot"Stems rot at the soil line. Plants collapse and die.A fine webbing of fungal growth may be seen between the infected stems and nearby soil particles."RhizoctoniaPlant in pasteurized potting media. Apply a fungicide to protect plants.
VirusesMosaic, malformed leaves, pale yellow ring spots, severe chlorotic mottling of leaves or plant stunting may occur.Impatients necrotic spot, tobacco ring spot, broadbean wilt, cucumber mosaic, tobacco necrosis virus.Purchase plants free of symptoms. Discard infected plants. Plant in pasteurized potting media. Maintain good aphid and thrips control to reduce spread.


Powdery mildew lesions.


Bacterial leaf spot.

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