Once a flower or leaf disease is noticed, spraying with captan or mancozeb will often aid in controlling the disease. Read and follow all label directions when applying a fungicide to african violets. Root diseases usually result from over watering of plants. Symptoms may not show up on the leaves until severe root damage has occurred. In most cases with root diseases or damage the best control is to discard the plant and purchase new healthy ones.
Some problems caused by cultural factors include ring or leafspot and petiole rot.
Yellowish rings, spots or streaks on the upper surface of leaves are caused by cold water touching relatively warm leaves. This can be avoided by using water at room temperature or slightly warmer than leaf temperature. Petiole rot occurs when petioles touch the edge of the pot and develop brown, sunken areas at points of contact. The injury is localized and does not cause the petiole to rot unless disease organisms enter the wound. This trouble is the result of chemical injury caused by the accumulation of soluble salts at the pot rim of clay pots.