My crape myrtle leaves have long white hairs, and a few drops begin to wither. What should I do?

Because of the powdery mildew of Lagerstroemia indica, white powder grows on its leaves. Powdery mildew of Lagerstroemia indica is a worldwide disease with a wide range of hosts, and Lagerstroemia indica is an important target of its invasion. Powdery mildew of Lagerstroemia indica occurs in all provinces and cities where Lagerstroemia indica is planted in China. After the onset of Lagerstroemia indica, the leaves often turn yellow and fall off, which directly affects the tree potential and ornamental effect.

The control methods of Lagerstroemia indica powdery mildew are as follows:

① Horticultural control: Lagerstroemia indica has strong germination ability. For seriously ill plants, all the branches of the current year can be cut off and burned in winter to completely eliminate the source of the disease. If Lagerstroemia indica planted at home is found to be infected with powdery mildew, the diseased leaves should be removed in time and the potted flowers should be placed in a ventilated and light-transmitting place. In field cultivation, we should control planting density, strengthen daily management, pay attention to increasing the application of phosphorus and potassium fertilizer, control the application of nitrogen fertilizer, and improve plant disease resistance.

(2) Chemical control: In areas with serious diseases, Bomei 3-4 degree stone sulfur mixture can be sprayed on branches before germination in spring; In the growing season, 80% zineb wettable powder can be sprayed 500 times, 70% thiophanate methyl 1000 times, 20% triadimefon EC 1500 times and 50% carbendazim wettable powder 8000 times.