What is the reason why the leaves of Paeonia lactiflora burn like coke? How to save it?

The following information comes from a flower friend in the flower shop uncle's flower friend group who has a flower cultivation problem. Wuxi Li Hong: The leaves of peony are all burnt, but they are still standing, and the color slowly turns yellow-green. There is nothing we can do about it. What is the reason? How to save it? According to the pictures provided by Huayou, it looks like leaf mold, which is one of the common diseases of Paeonia lactiflora. Six common peony diseases 1. Leaf mold Leaf mold is a serious disease. Peony will wither and die easily if it suffers from leaf mold. At the beginning of the disease, purple-brown spots will appear on the leaves. With the severity of the disease, it will become dark green mildew and spread to the whole plant. In autumn, the spots on leaves are dark brown. The disease mainly occurs in April-May, and the incidence rate is high in humid environment. 800~ 1000 times of bacteria or carbendazim should be cleaned up in time, and attention should be paid to strengthening ventilation. 2. Black Spot Black Spot is a common disease in the growth of Paeonia lactiflora. The main part of the disease is in the leaves. First, form a specific spot on the leaf. As time goes on, the area of the spot will gradually expand, and finally the leaves will fall off and die. The main onset time of black spot disease is July-September. Pay attention to cleaning branches and leaves in autumn to avoid infecting healthy leaves. 40% sterile Dan wettable powder can be diluted 500 times and applied to peony. 3. Tinea occurs on leaves. At first, it was a brown circular spot, which expanded toward the center and became brown or dark brown. Lesions usually connect in an irregular shape and then dry up. The disease invades from the wound, with poor ventilation, high temperature and high humidity. Strengthen ventilation and pay attention to spraying 800~ 1000 times of chlorothalonil or carbendazim for prevention and control. 4. Powdery Mildew Powdery Mildew is difficult to find in the early stage of the disease. Generally, powdery mildew mostly occurs on hidden branches and leaves, and when we find it, the incidence of powdery mildew will be more serious. At the early stage of the disease, leaves will be covered with white filaments, and white mildew spots will appear on roots and petioles, which proves that powdery mildew has appeared. How to treat powdery mildew? Pay attention to the daily maintenance of peony. If powdery mildew is found, it should be treated in time. The wound should be sprayed with 70% thiophanate-methyl wettable powder and diluted by 800- 1000 times, and then placed in a ventilated environment to prevent secondary infection. 5. Rust is also a very easy disease of Paeonia lactiflora. In the early stage of rust, yellow spots will appear on the leaves and the back of the leaves will spread slowly. Finally, many leaves will wither and die. Generally speaking, the onset time of rust is around May. If the peony is rusty, we can dilute it 400 times with 97% sodium rust and water it. 6. Epidemic diseases can invade leaves, petioles and stems. The diseases of leaves mostly start from the lower surface of leaves, with water spots, gray-green center and dark green edge, and then the leaves wither and die. 800- 1000 times of chlorothalonil or carbendazim can be sprayed, and 400 times of copper and mercury can be sprayed for prevention and control.