How to prevent and cure magnolia spot disease?

How to prevent and cure magnolia spot disease? Please give guidance on Magnolia spot disease: first, symptoms: also known as brown spot, leaf spot, mainly harmful to leaves. The primary yellow to light brown dots, then expanded into nearly round to irregular large spots, with reddish-brown lines on the edge, gray-white in the middle, and black particles scattered in the later stage of the disease, that is, the conidium of the pathogen. It is a semi-known fungal fungus, which causes early defoliation seriously. It happened from August to September. 2. Morphological characteristics of pathogens: conidia brown to dark brown, initially buried under the epidermis of Magnolia, then exposed, spherical to flask-shaped, 85-112 microns in size. Conidia round to oval, unicellular five colors, size 5-7 × 4-5 (micron). Third, the regularity of the disease: the pathogen overwintered on the diseased part or fallen leaves with mycelium or conidia. When the temperature and humidity were suitable in the next year, conidia were produced, and the primary infection and re-infection were carried out by wind and rain transmission. The soil is barren and the disease is serious in continuous rain. Fourth, control methods: 1, reduce the source of bacteria: timely removal of diseased fallen leaves, concentrated burning or deep burial. 2. At the initial stage of the disease, 1000-1500 times liquid of Bishi shark, 1000 times of 50% carbendazim wettable powder or 50% methyl thiophanate wettable powder were sprayed once every 10-15 days for 2-3 times. 3. The disease can be effectively controlled by spraying Bacillus thuringiensis, carbendazim, amiceda, etc. Click for more magnolia planting techniques click to get more flower planting techniques