What Is Astragalus Powdery Mildew? Detailed Guide to Symptom Identification and Control Methods
What is Astragalus powdery mildew? How to control it? Astragalus powdery mildew 1. Disease symptoms: Powdery mildew mainly damages Astragalus leaves. In the early stage, white powdery spots appear on both sides of the leaves, and in severe cases the entire leaf is covered with a layer of white powder, with white powder also present on petioles and stems. Affected plants often drop their leaves early, and yield is damaged. Onset...
What is Astragalus powdery mildew? How to control it?
Astragalus powdery mildew
1. Disease symptoms:
Powdery mildew mainly damages Astragalus leaves. In the early stage, white powdery spots appear on both sides of the leaves, and in severe cases the entire leaf is covered with a layer of white powder, with white powder also present on petioles and stems. Affected plants often drop their leaves early, and yield is damaged. The incidence rate is generally 10%-30%, and in severe cases can reach more than 40%. Astragalus pods and stems can also be affected.
2. Disease pattern:
The pathogen produces cleistothecia, which overwinter on diseased plant debris. When temperature and humidity are suitable in the summer of the following year, the ascospores inside the cleistothecia burst out of the fruiting bodies and spread widely, causing primary infection. The pathogen produces large numbers of conidia on the diseased parts of the host, which spread through the air and cause secondary infection. Ascospores and conidia are mainly spread by air. Hot and humid climatic conditions favor spore germination and infection, while dry climates favor the spread of conidia. Extensive cultivation management and improper fertilization and watering, especially excessive application of nitrogen fertilizer, easily cause excessive vegetative growth of plants and favor the occurrence of the disease. The mycelium can overwinter on Astragalus buds and can also cause disease the following year, continuing to cause damage until harvest.
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