Detailed Guide to Lotus Root Planting Time and Pest and Disease Control Techniques

Lotus root is a plant that grows in marshy areas and is one of the Eight Aquatic Immortals. Lotus root tastes crisp and slightly sweet; it can be cooked as a dish or eaten raw, is rich in certain nutritional value, and is an excellent nourishing ingredient. The main producing area of lotus root in China is mainly Hubei, and below we will take a look at when lotus root is generally planted, along with pest and disease control techniques.

I. When is lotus root generally planted?

The planting time of lotus root is related to both region and temperature. Generally, the best time suitable for planting lotus root is March and April each year. The most suitable temperature for lotus root growth is about 20 to 30 degrees, so the earliest temperature for planting lotus root must also reach above 15 degrees, otherwise the survival rate is not high. The temperature difference between southern and northern China is somewhat large, so the south generally plants lotus root in February and March, while the north starts a little later, in April and May.

II. Lotus Root Pest and Disease Control Techniques

1. Lotus root brown spot disease

A common disease on lotus leaves, producing light brown lesions on the leaves and causing localized drying of diseased leaves.

Control: plant at a reasonable density to ensure ventilation and light transmission in the lotus field; appropriately increase the application of phosphorus and potassium fertilizers to improve plant resistance, and promptly remove diseased plant residues. In the early stage of the disease, spray with 25% carbendazim 600 times solution, or 75% chlorothalonil 1000 times solution.

2. Lotus root rot disease

Also called wilt disease, it infects the underground stem and causes rot; in severe cases the whole field turns yellow and withered, as if burned by fire.

Control: implement a 2-3 year crop rotation in severely diseased fields. Commonly use 70% thiophanate-methyl 1000 times solution or 75% chlorothalonil 800 times solution to spray and seal the seeds, cover with agricultural film and keep sealed for 24 hours, then dry and plant. Deeply plow the lotus field and apply 150 kg of lime per mu. When the disease occurs, mix 0.5 kg of 75% chlorothalonil with 30 kg of dry soil and spread it evenly into the shallow-water field.

3. Lotus root black spot disease

Also called brown streak disease, it occurs only on leaves; in severe cases the lesions merge and the leaves turn yellow and withered.

Control: in winter, thoroughly remove diseased and residual leaves in the field and burn them in a centralized manner. In the early stage of the disease, remove diseased leaves and spray for control. Commonly use 70% thiophanate-methyl 1000 times solution, or 65% zineb 600 times solution, or 1:1:160-200 Bordeaux mixture, spraying once every 10-15 days for a total of 2-3 sprays.

4. Lotus root streak virus disease

After infection, symptoms can appear on both lotus leaves and underground rhizomes. Large polygonal to irregular light brown necrotic spots form on the leaves, and dark brown anthracnose streak spots form on the rhizome epidermis.

Control: select disease-resistant varieties, promptly control aphids (the virus transmission vector), and in the early stage of the disease spray 1.5% plant virus inhibitor emulsion 1000 times solution.

5. Common pests and diseases

These include aphids, large bagworms, pear green nettle moths, and brown nettle moths, which damage standing leaves and flower buds. Spray with 90% trichlorfon 800-1000 times solution, or 40% dimethoate 2000 times solution.