What are the control methods for Sophora flavescens leaf blight
Sophora flavescens, also called Shanhuai root, is a perennial semi-woody plant of the Fabaceae family. Its rhizome is used medicinally and has the effects of clearing heat and drying dampness, promoting urination, and dispelling wind and killing parasites. It originally grew wild throughout the country, with relatively large yields in Shanxi, Hubei, Henan, Hebei, and Xinjiang. It likes warm and humid environments, is cold-resistant, and can overwinter in the field. It can grow beside ditches, along roadsides, in forests, and in wasteland, and grows well in sandy or semi-sandy soil. Because its medicinal effect is remarkable and it has no side effects, its usage is increasing, while wild resources are being dug up less and less. Sophora flavescens can be planted in spring and summer, in the same way as planting beans.
Physiological characteristics
The root of Sophora flavescens is long and cylindrical, often branched in the lower part, 10-750px long and 1-162.5px in diameter. The surface is grayish brown or brownish yellow, with longitudinal wrinkles and transversely elongated lenticel-like protrusions. The outer bark is thin, mostly split and curled back, easy to peel off, and the peeled area is yellow and smooth. The texture is hard and not easy to break, and the cross-section is fibrous; slices are 3-6mm thick; the cut surface is yellowish white, with radial texture and cracks, and some have anomalous vascular bundles arranged in concentric rings or irregularly scattered. It has no strict requirements for soil and can generally grow on sandy loam and clay loam. It is a deep-rooted plant, so plots with a low groundwater table and good drainage should be selected for planting. Seedlings sown in the same year mostly do not bloom. In winter the leaves turn yellow and fall off as the plant enters dormancy, and it turns green and grows again in the following spring. It buds in June and blooms, and the fruit matures from July to mid-August. It grows in sandy land or in grass clumps on sunny slopes and beside streams and ditches.
How to control Sophora flavescens leaf blight?
Damage symptoms of Sophora flavescens leaf blight
This disease mainly harms the leaves of Sophora flavescens. The lower leaves of the plant are affected first, then it gradually spreads upward. In the early stage of the disease, small brown round spots appear on the leaf surface; afterward the spots continue to expand, and the center becomes grayish brown. Finally the leaves scorch and the plant dies, seriously affecting the yield of Sophora flavescens.
2. Control measures
1. Select healthy seeds and soak them in 1:1:100 Bordeaux mixture for 10 minutes before sowing.
2. Apply more phosphorus and potassium fertilizer to enhance the plant's resistance to disease; after rain, open ditches in time to drain water and reduce field humidity.
3. Chemical control. In the early stage of the disease, spray with 50% carbendazim 600-fold solution, 65% zineb 600-fold solution, or 50% zineb 500-fold solution, at an interval of 10-15 days, for 2-3 consecutive sprays.