Leaf gall reduces the ability of azaleas to produce flowers the following spring, since heavily diseased plants lose many of their leaves needed for food manufacture.
Infected leaves become fleshy and severely distorted.
As the galls form, affected parts may become whitish or light green. Sometimes a fleshy rosette of leaves appears at the tip of a branch, or a gall becomes bladder-like as it decays and dries out. Azaleas are most susceptible to leaf gall when young leaves appear, and like flower blight, is most severe following periods of rainy weather. Infection cycles occur as long as young leaves are present on plants. The best control measure is to remove the galls when they are first noticed.