Powdery mildew.  This is a fungal infection that appears in the spring and continues through out the growing season.  Leaves, buds and flowers become whitened, contorted and dwarfed as the fungal filaments and spores rapidly spread over the entire plant.  It also attacks other plants such as roses, peaches, aspens and oaks.  Prune the shrubs to thin out any dense foliage, and plant in open areas where they won’t be crowded and are exposed to sunlight and breeze.  Avoid excessive nitrogen fertilizer; this fungus typically infests succulent new growth.  Clean away any fallen leaves since they may harbor spores.  Irrigate with a soaker hose or drip lines to avoid wetting the foliage.