A Detailed Explanation of the Harm and Control Methods of Angelica Sclerotinia Rot

The pathogen of Angelica sclerotinia rot (Sclerotinia SP) is a fungus of the genus Sclerotinia in the subphylum Ascomycotina. The sclerotia are borne on the plant surface or on aerial hyphae in the internal cavities of plant organs, resembling mouse droppings, irregular in shape, and composed of hyphae.

1. Harmful symptoms: It mainly harms roots and leaves. In the early stage of the disease, the leaves turn yellow; in the later stage, the plant wilts, and the root tissue rots to form cavities containing multiple black, mouse-dropping-shaped sclerotia.

2. Disease occurrence pattern: The pathogen overwinters as sclerotia in seeds, diseased seedlings, diseased residues, or soil, and forms ascocarps from December to February-March of the following year, producing ascospores that spread by wind and rain, expanding the damage. This fungus is a low-temperature disease; low temperature and high humidity, abundant weeds, and extensive management favor its occurrence.

3. Control measures

① Collect, remove, and burn diseased plants and sclerotia in the soil to eliminate the source of the pathogen.

② Practice paddy-upland rotation to eliminate sclerotia in the soil.

③ Establish disease-free seedling bases, select disease-free seedlings for transplanting, and soak them in 0.05% amobam for 10 minutes before transplanting to disinfect the seedlings.

④ In the early stage, promptly pull out diseased plants, dig out the soil from diseased holes, and disinfect with quicklime to prevent the spread of the disease.

⑤ In the early stage of the disease, spray 600-fold 65% zineb or Bordeaux mixture (1:1:300), or drench with 300-fold dimethirimol.