When night temperatures are cool, day temperatures warm, and moisture conditions high, the pathogen readily sporulates on both leaves and flowers, covering them with grayish-green, dusty masses of spores. Cuttings rooted during the winter are especially susceptible to Botrytis blight since the environment is ideal for the disease and very poor for rapid growth of the plant. Episcia, Sinningia, and African violets are also commonly affected by Botrytis blight. Control - Controlling Botrytis blight is particularly important during the winter months. Cultural methods which improve foliage drying and reduce moisture condensation on foliage during the night reduce Botrytis blight.
Spots can appear on margins or blades and are sometimes irregular or donut-shaped and white.
Control - Water that is colder than the leaf surface will cause spotting and is most common in Florida during winter. Deep well water is usually near 70 F and rarely causes problems, except when it is stored in outdoor tanks. Be sure temperatures of overhead water applications are near leaf-surface temperatures. Leaf drop may also occur. Control - Use the same cultural controls as mentioned for Botrytis blight.