Bacterial leaf spot causes brown V-shaped lesions on the leaf margins. The spot shapes can be small and circular or irregular. The problem may be worse on older leaves. Infected leaves droop. When the bacteria moves into the sap stream the entire plant declines.
Black leg causes plant stems to turn black.
Black stem rot is most serious on cuttings but can attack mature plants. The disease starts at the stem base and works upward causing progressive blackening. Odema causes leaf spots during the winter. Give the plants more light and slightly less water. Visuals associated with this text.