Danshen Pest and Disease Control Methods and Key Technical Points

1. Leaf spot disease: A bacterial disease. Nearly round or irregular dark brown lesions appear on the leaves. In severe cases, the lesions expand and merge, causing the leaves to wither and die. It first appears in early May and continues until late autumn. Control methods: Remove diseased leaves at the base, improve ventilation conditions, and pay attention to drainage; clean the garden in winter and dispose of the remaining plant debris.

2. Sclerotinia rot: The stem base, bud head, and rhizome parts of affected plants gradually rot and turn brown, and black mouse-dropping-like sclerotia and white mycelium develop on the affected parts, the nearby soil surface, and inside the stem base, causing the plants to wither and die. Control methods: Strengthen field management, dredge ditches and drain water promptly; implement paddy-upland rotation.

3. Root rot: Occurs from May to November. The roots of affected plants are damaged and rot first, with the outer skin turning black; aboveground, individual stems and branches wither and die first, and in severe cases the whole plant dies. Control methods: Rotation, and continuous cropping should be avoided; choose high, dry, and well-drained plots for planting, and pay attention to drainage during the rainy season; select healthy, disease-free seedlings; in the early stage of the disease, irrigate with a 50% thiophanate-methyl 800-1000 times dilution.

4. Root-knot nematode disease: Many tumor-like nodules form on the fibrous roots, and the aboveground part of the plant is short and chlorotic. It is caused by parasitism by root-knot nematodes. Control methods: Establish disease-free seed propagation fields and implement quarantine to prevent diseased propagation material from entering disease-free areas; rotate with gramineous crops and avoid continuous cropping.