How to prevent crape myrtle brown spot?

Symptoms of Lagerstroemia indica brown spot: Lagerstroemia indica brown spot mainly harms leaves, and the lesion is nearly round, purple-brown to grayish brown, with a size of 2 ~ 8 mm. When wet, there are black mildew spots (conidia and conidia) on both sides of the lesion. In the later stage, the diseased spots developed and became pieces, which made the whole leaf yellow and fall off.

Control measures: (1) Horticultural management: Remove fallen leaves before late autumn and winter to reduce the source of infection at the beginning of next year.

(2) Chemical control: At the initial stage of the disease, spray 1000 times 50% chlorpheniramine wettable powder, 12% green milk copper, 800 times 77% carbendazim wettable powder, or 1500 times 65% metronidazole wettable powder in time.