The Latest Control Methods for Common Pests and Diseases of Isatis indigotica

Isatis indigotica, also known as indigo root and blue indigo root, is a Chinese medicinal herb we are all familiar with. It has the effects of clearing heat and detoxifying, cooling the blood and soothing the throat, and is mainly used to prevent colds and fever. However, during the cultivation of Isatis indigotica, it suffers from quite a few pests and diseases, which affect its growth and yield and cause economic losses to herb growers. Below, the editor will introduce the control methods for common pests and diseases of Isatis indigotica.

1. Downy mildew

The disease starts on the leaves at the base of the plant stem and gradually spreads upward. When it occurs, a gray downy mold appears on the underside of the leaves, while there are no obvious lesions on the upper surface. The lesions become uneven and bumpy, and as the disease worsens further, the lesions turn into chlorotic round spots and gradually become brown necrotic spots. In severe cases, the necrotic spots merge into large patches, eventually causing the leaves to dry up and die.

Control methods: Clean the field at harvest time to reduce overwintering sources of the disease, strengthen field management, plant at a reasonable density, and pay attention to ventilation and light penetration. When the disease occurs, spray Bordeaux mixture or zineb solution to prevent the disease from spreading further.

2. Root rot

It mainly damages the root system of Isatis indigotica plants. The fibrous roots and the root tips of the main root are affected first. When the disease occurs, the affected parts of the root system turn dark brown, and the vascular bundles of the root system show brown lesions. In the late stage of the disease, the entire root system rots, and the aboveground plant gradually wilts due to lack of nutrients and water until it dies.

Control methods: Use reasonable crop rotation, choose well-drained soil for planting, and when the disease occurs, drench the planting holes with carbendazim or thiophanate-methyl for better control results.

3. Sclerotinia rot

Sclerotinia rot can harm the entire plant, affecting the roots, stems, leaves, pods and other parts. When the stem is infected, the surface rots, the stalk splits into a tangled hemp-like mass and is covered with mycelium, and black mouse-dropping-like sclerotia are present inside and outside the stem. When the leaves are infected, water-soaked bluish-brown lesions appear, and later the leaves rot, leaving only the veins.

Control methods: Rotation between paddy fields and dry land can effectively reduce the pathogen. During the rainy season, pay attention to drainage to lower field humidity, plant at a reasonable density, and enhance ventilation and light penetration. When the disease occurs, spray with a 600-fold dilution of 65% zineb for control.

4. Aphids

Aphids are a common pest of Isatis indigotica. After being damaged by aphids, the plants suffer severe water loss, curl, twist and turn yellow, seriously affecting yield and medicinal value.

Control methods: When planting, keep away from cruciferous crops, reduce and clear weeds as well as diseased residues from the previous crop to reduce pest sources. When the pest occurs, spray with the highly effective and low-toxicity pesticide cypermethrin for control.

The above are the control methods for common pests and diseases of Isatis indigotica. We hope they can help you. For more related knowledge, please stay tuned to us.