What are the control methods for chrysanthemum powdery mildew?
How do you prevent and control chrysanthemum powdery mildew? Please advise. Chrysanthemum powdery mildew mainly occurs on the upper leaves, stems and buds of the chrysanthemum. The affected parts are covered with a layer of grayish-white mycelium, which spreads from spots into patches, forming a layer of dirty-white powdery substance, causing the leaves to become deformed and the buds to fail to open normally, which affects their ornamental value. The main cause is rainy...
How do you prevent and control chrysanthemum powdery mildew? Please advise.
Chrysanthemum powdery mildew mainly occurs on the upper leaves, stems and buds of the chrysanthemum. The affected parts are covered with a layer of grayish-white mycelium, which spreads from spots into patches, forming a layer of dirty-white powdery substance, causing the leaves to become deformed and the buds to fail to open normally, which affects their ornamental value.
The main causes are frequent rainy weather, insufficient light, poor drainage and high humidity, which allow the pathogen to reproduce quickly and cause the disease to spread. However, under drought conditions the disease can also become more severe. In addition, excessive nitrogen fertilizer, lodging of the plants, or insufficient fertilization leading to weak plant growth and poor disease resistance can all easily trigger the occurrence of powdery mildew.
Control methods: 1. Strengthen management: rationalize fertilizer and water, improve care, and enhance the plant's own disease resistance. 2. Chemical control: at the early stage of the disease, spray 20% triadimefon emulsifiable concentrate at 800 times dilution, or 50% thiophanate-methyl wettable powder at 1000 times dilution, or 50% carbendazim wettable powder at 500 times dilution. Be sure to alternate the use of the above chemicals. As long as control is timely, powdery mildew will not cause damage.
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