High humidity, poor air circulation, and low light intensity contribute to the development of this disease. Spores of the pathogen are spread by direct contact of leaves. Spacing the plants so that the leaves of adjacent plants will not touch reduces spreading to healthy plants. Since infection by Botrytis often follows mite injury, controlling these pests aids in controlling the disease. The application of a foliar fungicide may be needed to control severe outbreaks.
Powdery mildew is a light grey, powdery substance on the stems and petioles.
This shortens the life of blooms and makes the violet unthrifty. Mildew grows in cool, moist, stagnant air. Karathane is a good control, as is dusting sulfur when a very small amount is blown lightly over the plants. Insects and mites occasionally damage the foliage and flowers of African violets. Cyclamen mites feed in the plant crown, causing young leaves and new growth to be stunted, twisted, discolored, and brittle.