Answer: Azalea leaf gall is a disease that begins as a thickened, fleshy growth of leaf tissues, progresses to powdery white, and eventually to hard, brown galls. Its a fungal disease promoted by high humidity and poor air circulation. Cut the galls off the plant, including any stems that are infected. This will help improve air circulation, as well. Powdery mildew is another fungal disease that many azaleas are prone to contracting. Remove the affected plant parts, rake and remove fallen leaves, and try pruning to open the plant up to better air circulation. If you can keep moisture off the leaves of the plant by applying water directly to the soil, you'll reduce the humidity around the plant and remove one of the causes of fungal growth. There are garden fungicides that will protect the uninfected leaves of your azalea, but prevention of fungal diseases is easier than stopping the disease in progress!
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