What are the control methods for sweet osmanthus brown spot disease?
How to control brown spot disease in sweet osmanthus? Please provide guidance. Brown spot disease is a common disease of sweet osmanthus, caused by infection with fungi of the Deuteromycotina. It occurs in both field-grown and potted sweet osmanthus plants. When it occurs, mild cases affect the ornamental effect, while severe cases cause plant death. Symptoms mostly occur on leaves, mostly starting from the leaf tip...
How to control brown spot disease in sweet osmanthus? Please provide guidance
Sweet osmanthus brown spot disease is a common disease of sweet osmanthus, caused by infection with fungi of the Deuteromycotina. It occurs in both field-grown and potted sweet osmanthus plants. When it occurs, mild cases affect the ornamental effect, while severe cases cause plant death.
Symptoms They mostly occur on leaves, mostly spreading from the leaf tip and leaf margin to the entire leaf. In the early stage, the lesions are light gray, then expand in an irregular fan shape. In the later stage, the lesions gradually dry up, turn brown, and bear black granular bodies.
Occurrence pattern The pathogen overwinters on diseased plant residues and spreads through wind, rain, watering, and other means. For outdoor care in northern regions, the disease is most severe from late spring to mid-autumn.
Control methods 1. Promptly remove diseased plant residues; 2. Strengthen water and fertilizer management to enhance the plant's disease resistance; 3. The cultivation environment should be ventilated and well lit, and sprinkling irrigation should not be used during the disease period, avoiding rain exposure; 4. Promptly control piercing-sucking pests such as scale insects and aphids; 5. Before bringing plants indoors in late autumn, spray twice with 70% mancozeb wettable powder at 500 times dilution for control; 6. If occurrence happens, use 90% chlorothalonil at 500 times dilution or 50% carbendazim at 500 times dilution for control.
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