Bark characteristics, flower color, fall color, plant size and shape, and disease resistance have been greatly improved in recent years as the result of private, state, and federally funded breeding programs. See the table on page 5 for cultivars for Mississippi landscapes. Diseases Powdery Mildew . The major disease affecting crapemyrtles is powdery mildew. This fungal disease reduces flower performance and weakens plants by attacking flower buds, growing shoot tips, and young leaves.
Powdery mildew is most common when cool nights are followed by warm days.
It occurs most often in crowded, low areas with poor air circulation. The fungus over-winters in diseased plant debris on the ground and on the dormant shoot buds. Powdery mildew infection appears as slightly raised, blister-like areas on young leaves. The leaves are soon covered with a grayish-white powdery fungal growth. As leaves expand, they become curled and distorted.