MySheen

Harm and control of powdery mildew of Angelica sinensis

Published: 2024-11-25 Author: mysheen
Last Updated: 2024/11/25, The pathogen of powdery mildew of Angelica sinensis (ErysipheSP.) belongs to ascomycetes subphylum powdery mildew. The closed capsule accumulates and is buried in the mycelium, spherical or oblate, black or dark brown. The obturator shell contains 6 sub-cysts of 3 Mel. The ascus is subglobose, ovate, colorless, short stalked, thick membrane, and contains 6 ascospores. Ascospores are oval, colorless and transparent, unicellular. The main results are as follows: 1. the harmful symptom is harmful leaves. At the initial stage of the disease, gray-white powdery spots appeared on the leaf surface, and then enlarged and converged into large spots.

The pathogen of powdery mildew of Angelica sinensis (ErysipheSP.) belongs to ascomycetes subphylum powdery mildew. The closed capsule accumulates and is buried in the mycelium, spherical or oblate, black or dark brown. The obturator shell contains 6 sub-cysts of 3 Mel. The ascus is subglobose, ovate, colorless, short stalked, thick membrane, and contains 6 ascospores. Ascospores are oval, colorless and transparent, unicellular.

The main results are as follows: 1. the harmful symptom is harmful leaves. At the initial stage of the disease, gray-white powdery disease spots appeared on the leaf surface, then expanded and converged into large spots, and small black particles appeared, and finally the leaves turned yellow and withered.

2. The regularity of the disease occurs when it is hot and dry in summer. The pathogen overwintered on the diseased remains or seed roots in closed cysts or mycelia. The overwintering closed cysts emit mature ascospores in the coming year for primary infection. The overwintering mycelium directly produced conidia in the second year. During the growth of Angelica sinensis, mycelia, conidiophores and conidia were continuously produced on the outer diseased leaves, and the conidia were re-infected by airflow transmission. The optimum temperature for spore germination of Angelica powdery mildew was 18 ℃ ~ 30 ℃, the humidity was more than 75%, and the incubation period was 2-5 days. When the air relative humidity is low and there is no water film on the plant surface, the conidia can still germinate and invade, causing harm. Lack of water in soil, poor ventilation, extensive management, weak plant growth or overdense branches and leaves are all conducive to the occurrence of the disease.

3. Control measures ① seed treatment: soak the seeds in 500x formalin solution for 5 minutes or soak the seeds for 2 hours. ② pulled out the diseased plant in time and burned it centrally. ③ implements crop rotation to avoid continuous cropping. At the initial stage of the onset of ④, 1000 times of methyl topiramate or 65% of methylene thiophanate was sprayed every 10 days or so for prevention and treatment, for 3 consecutive times. ⑤ strengthens the field management and enhances the disease resistance of plants.

 
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