MySheen

Disease knowledge Magnolia brown spot

Published: 2024-11-05 Author: mysheen
Last Updated: 2024/11/05, Symptoms: the pathogen mainly infects the leaves. The diseased leaves initially appeared light brown or yellow dots on the surface, one enlarged into round or irregular spots, 5-12 mm in diameter, dark brown at the edge, grayish white in the center, and many black dots on it. The disease spots can merge into amorphous large-scale necrotic damage. In general, the disease begins to occur in summer and the harm is more serious from August to September. Pathogen and disease status: Magnolia brown spot, also known as spot disease, is a common disease of Magnolia magnolia. Magnolia mandshurica is cultivated in all the areas in China, such as Suzhou, Nanjing, Wuhan,

Symptoms: the pathogen mainly infects the leaves. The diseased leaves initially appeared light brown or yellow dots on the surface, one enlarged into round or irregular spots, 5-12 mm in diameter, dark brown at the edge, grayish white in the center, and many black dots on it. The disease spots can merge into amorphous large-scale necrotic damage. In general, the disease begins to occur in summer and the harm is more serious from August to September.

Pathogen and disease status: Magnolia brown spot, also known as spot disease, is a common disease of Magnolia magnolia. Magnolia mandshurica occurred in all the areas cultivated in China, especially in Suzhou, Nanjing, Wuhan, Shenzhen, Tianjin, Shenyang and so on. The disease is serious and often causes a large number of fallen leaves, affecting the landscape.

Prevention and control measures:

1. Magnolia should be planted in places where the soil is fertile and sunny. On the barren soil. It is necessary to apply more fertilizer to strengthen the tree potential and improve disease resistance.

2. Whether in the courtyard or in the street green belt, it is necessary to remove the diseased leaves in time and destroy them centrally. The seedlings in the nursery should pay more attention to sanitary management, remove diseased leaves as soon as possible and reduce the source of infection.

3. The initial stage of the disease in summer every year. It can be sprayed with 100-fold Bordeaux liquid for protection. In the future, 50% methyl thiophanate wettable powder or 75% chlorothalonil wettable powder can be sprayed 800-1000 times to control the spread of the disease.

 
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