Latest Causes of Lotus Root Leaf Blight and Detailed Control Measures

Lotus root is a vegetable loved by many people, and it is grown in quite a few regions, but growing lotus root is not a simple matter. If the lotus seed is not chosen well, the water depth of the lotus field is not managed properly, or the temperature is too high when topdressing, these problems can all lead to planting failure. And many farmers also encounter the phenomenon of dead leaves on lotus root when growing it. What causes this? How should it be prevented and controlled? Let's find out together.

I. Causes of Dead Leaves on Lotus Root

The reason lotus root leaves wither early is leaf blight of lotus root, a fungal disease that is easily overlooked. When the disease is mild, it weakens the growth vigor of lotus root; when severe, it causes the entire leaf to wither and die. Moreover, because the leaves are damaged, the photosynthesis of lotus root runs rampant, and the lotus root and lotus seeds cannot obtain nutrients, so yield and quality are seriously affected. The main reasons for the occurrence of leaf blight are the lack of scientific management methods during lotus root cultivation, or inadequate cultivation techniques, failure to sterilize and disinfect the lotus seed, insufficient topdressing, and other reasons, all of which can cause leaf blight in lotus root.

II. Symptoms of Leaf Blight

Leaf blight of lotus root mainly occurs on the leaves. In the early stage of the disease, pale yellow lesions appear on the leaf margins of the lotus leaf surface and gradually spread toward the center of the leaf, causing the lesions to gradually change from pale yellow to yellow-brown, and the leaf margins become scorched and withered. As the disease progresses, the damage also spreads from the mesophyll to the veins, the color of the lesions turns dark brown, and the entire leaf dries up and dies, looking like it has been burned from a distance. The pathogen of leaf blight overwinters on diseased residues and becomes the initial infection source for the following year; it generally begins to occur at the end of May and the beginning of June, is most prevalent in mid-to-late June, peaks from July to August, and the incidence declines after September.

III. Control Measures

1. Reasonable crop rotation

When lotus root is grown for too many years, the pathogen accumulates excessively in the soil, so reasonable rotation is needed to control the occurrence of the disease. Generally, after 3 consecutive years of lotus root cultivation, or in fields with severe disease, rotation should be carried out. If rotation is not carried out, it is recommended to apply quicklime for sterilization.

2. Winter field cleaning

In winter, the lotus field should be cleaned up, and diseased residues should be completely eliminated and taken out of the field for centralized treatment. Diseased leaves should be removed in time and taken out of the field to be deeply buried or burned.

3. Reasonable fertilization

Farmyard manure applied must be fully decomposed, and quick-acting potassium fertilizer should be added to improve disease resistance.

4. Chemical control

In the early stage of the disease, spray 50% carbendazim or 50% thiophanate wettable powder at 800 times dilution, or 70% mancozeb wettable powder at 500-600 times dilution, spraying once about every week for 2-3 consecutive sprays, which gives a good control effect.

  The above is an introduction to the causes of dead leaves on lotus root and the control measures. We hope it can help you. If you want to learn more related knowledge, please stay tuned to us.