How to prevent and control pests and diseases of Polygala tenuifolia? A detailed practical guide

Polygala tenuifolia, also known as xiaocao, gangye yuanzhi, shancha ye and so on, is a commonly used traditional Chinese medicine. It was first recorded in the Shennong Bencao Jing, listed as a superior grade, and regarded as a vital tonic for preserving life, with functions of calming the mind, boosting intelligence, dispersing stagnation and resolving phlegm. During its growth it is easily harmed by pests and diseases, so control measures are needed. Let us take a look below at the pest and disease control techniques for Polygala tenuifolia!

Root rot

[Damage characteristics] In the early stage of root rot, the roots and rhizomes partially turn brown and rot, the base of the leaf stalk develops brown, prism-shaped or oval rotting spots, and finally the base of the leaf stalk rots away completely, the leaves wither and die, and the rhizome decays.

[Control methods] Detect early, pull out and burn promptly; disinfect the diseased holes with 10% lime water. In the early stage of the disease, 50% carbendazim 1000-fold solution can also be used for spraying and drenching, once every 7-10 days, for 2-3 consecutive sprays. 

Leaf blight

[Damage characteristics] The disease starts on the lower leaves of the plant and gradually spreads upward. In the early stage, small brown round spots appear on the leaf surface, then the lesions continuously expand, the center turns grayish brown, and finally the leaves scorch and the plant dies.

[Control methods] Spray the leaves with mancozeb 800-1000-fold solution or ridomil 800-fold solution, generally once every 7 days; two sprays can bring the damage under control. 

Aphids

[Damage characteristics] They harm the young leaves of the plants from late May to early June.

[Control methods] They can be killed by spraying with 40% dimethoate emulsifiable concentrate 2000-fold solution, once a week; two sprays are enough to bring the damage under control. 

Bean blister beetle

[Damage characteristics] It occurs from June to August and harms leaves and tender stems.

[Control methods] Spray with decamethrin at 5-10 mg/L for control, for 2 consecutive sprays 5-7 days apart, which can kill them all.