A Detailed Guide to the Latest Symptoms and Control Methods of Lotus Root Rot
Lotus root rot is the main disease in lotus root cultivation, with a wide distribution range and common occurrence. It can occur throughout the entire growth period, and the degree of disease occurrence varies greatly between intervals, plots, and years. The severity for lotus root varies; when mild, losses are relatively small, but when severe, plants die in patches, seriously affecting yield and quality. So how should lotus root rot be controlled? Let's find out together.
1. Disease Symptoms
This disease mainly damages the underground stem nodes, causing lotus root to turn brown and rot, and the aboveground plants to turn brown and die. After the stem nodes are infected, the initial symptoms are not obvious. As the disease develops, the underground stem nodes gradually turn brown and the discoloration expands, spreading to newly formed underground stem nodes. In severe cases, the entire underground stem nodes turn brown and rot and become inedible. Because the underground stem nodes are harvested, the plant's vascular tissue is blocked, and the aboveground leaves gradually fade to yellow, with leaf margins turning brown, drying up or curling inward, ultimately causing the top of the leaf stalk to bend, turn brown, and dry up. In severe cases, the entire lotus field turns yellow and withered, as if burned by fire, and when digging up, thread-like mycelium and pink sticky matter can be seen on the lotus nodes.
2. Disease Development Pattern
The pathogen overwinters as mycelium in seed lotus roots and soil. Infected seed lotus roots and soil are the main sources of infection. When infected seed lotus roots are planted, the seedlings become central diseased plants after emergence, with lesions first occurring on the underground stem nodes and root system, gradually spreading to the leaf stalks and leaves. Central diseased plants produce large numbers of spores, which spread through water flow and invade through wounds, causing secondary infection. Infected seed lotus roots are the main factor in the occurrence and epidemic of this disease. In addition, due to differences in resistance among varieties, deep-rooted varieties are less affected than shallow-rooted varieties. The disease is easily triggered under conditions of continuous rain, insufficient light, or frequent storms. Factors such as poor ventilation in the lotus field, acidity, underground pest damage, application of undecomposed organic fertilizer, and excessive application of nitrogen fertilizer can all lead to severe disease.
3. Control Methods
Practice crop rotation with other crops for more than two years. Before planting, deep plow the soil, allow it to dry appropriately, and broadcast quicklime to disinfect and sterilize. When planting, choose varieties with strong disease resistance. Select disease-free seed lotus roots for sowing, and disinfect them with carbendazim solution before sowing. After planting, strengthen fertilizer and water management, apply decomposed organic fertilizer, reasonably balance nitrogen, phosphorus, and potassium fertilizers, and apply timely and appropriate topdressing during the growth period to prevent excessive nitrogen fertilizer application. Manage the water layer scientifically according to the needs of lotus at different growth stages, keeping the depth moderate, and use water to regulate temperature and fertilizer. When diseased plants are found, remove them promptly and apply medication to prevent spread. Available agents include carbendazim, shuangxiaoling, and dodine. Note to alternate the agents to avoid developing resistance.
The above is an introduction to the symptoms and control methods of lotus root rot. We hope it helps you. For more related knowledge, please stay tuned to us.