Control Methods and Technical Key Points for Angelica Root Rot

Angelica root rot, also known as root decay disease, is one of the main diseases during the growth and development period of angelica (Angelica sinensis), greatly affecting its yield and quality.

1. Damage symptoms: It harms roots and stems. The root tissue of affected plants initially turns brown, then rots into a water-soaked state, leaving only a fibrous hollow shell. The stem becomes brown and water-soaked, aboveground growth stops, and the plant becomes stunted. Elliptical brown patches appear on the leaves; in severe cases, the leaves wither, turn yellow, droop, and even the entire plant dies.

2. Pathogen: (Fusarium avenaceum (Fr.) Sacc.) belongs to the Deuteromycotina, genus Fusarium, a fungal pathogen. Conidia come in two types, large and small. Large spores are sickle-shaped, multicellular, with 1-5 septa; small spores are oval, borne in false heads, single-celled.

3. Disease occurrence pattern: The pathogen overwinters as mycelium and conidia in diseased field soil or on angelica seedlings, becoming the primary infection source for the following year. Disease begins in early May, causes severe damage in June, peaks in July and August, and gradually subsides in September as temperatures drop. The pathogen is mostly concentrated in the tillage layer of the soil. High temperature and high humidity favor disease occurrence. Frequent activity of underground pests creates more root wounds, which favors disease development. Continuous cropping exacerbates disease occurrence.

4. Control measures: (1) Choose sandy soil with good drainage and strong water permeability as the cultivation site. Plant on high ridges and practice crop rotation. (2) Soil disinfection: Before transplanting, treat the soil with pesticides such as 70% quintozene or 70% dexon. (3) Select healthy, disease-free seedlings for transplanting. Before transplanting, soak in 1:1:150 Bordeaux mixture for 10-15 minutes, then air-dry before planting. Alternatively, during seedling raising, dress seeds with carbendazim or thiophanate at 0.3-0.5% of seed weight. (4) Promptly pull out diseased plants and burn them in a centralized manner. Apply a pinch of lime powder to the diseased holes, and spray the entire diseased area with 50% Tuzet at 600-1000 times dilution or 50% thiophanate at 800-1000 times dilution to prevent spread. (5) Strengthen field management, appropriately increase phosphorus and potassium fertilizer application, and carry out timely cultivation and weeding to improve plant disease resistance.