Wei Zihua has black spots and white spots on her branches. What disease did you get and how to prevent it?

Listen to you, your crape myrtle should be infected with powdery mildew. At the beginning of the disease, small white spots appeared on the leaves, which later expanded into circular spots. In severe cases, the leaves were twisted, withered and yellow, and fell off early, leading to dryness and death. In the later stage, there will be small particles that turn from white to yellow and then to black on the white powder layer. If the tender tip is infected, it will twist and turn white. The powdery spores of the disease are spread by airflow and can be reinfected many times during the growing season. Dead plants and fallen leaves should be thoroughly removed in autumn. In the growing season, diseased buds, diseased leaves and diseased branches should be removed in time and moved out of the garden for centralized treatment to reduce the source of infection. Drug treatment can spray 3000 times of 25% triadimefon wettable powder and 1000 times of 50% benomyl or 70% thiophanate-methyl wettable powder at the onset, which has good therapeutic effect.