The Latest Prevention and Control Measures for Common Physiological Diseases of Vegetables at the Seedling Stage
Physiological diseases often occur during the process of raising vegetable seedlings. Physiological diseases differ to some extent from infectious diseases in both their symptoms and their prevention and control. So what are the common physiological diseases in vegetable seedling raising? How should they be prevented and controlled? Let's take a look together.
1. Root burn
Because too much nitrogen fertilizer is applied, the seedbed soil is dry, and applying undecomposed organic fertilizer causes damage to the seedling root system. It generally shows as yellowing root tips, few and broken fibrous roots, no new roots, but brown roots; the aboveground leaves are small, wrinkled, dark green in color, with scorched yellow edges. In severe cases, it can cause the seedlings to die in patches.
Prevention and control measures: When applying chemical fertilizer at the vegetable seedling stage, do not apply too much and apply it evenly; use decomposed organic fertilizer as much as possible. When root burn occurs, appropriately water more to reduce the fertilizer concentration in the seedbed soil, or replace the soil and transplant, which can very effectively address fertilizer-induced root burn.
2. Root rot
Root rot is caused by excessively saturated soil moisture in the seedbed. When soil moisture is high, air is lacking, and it is also caused by being in a low-temperature and insufficient-light environment for a long time. It mainly shows as root decay; the seedlings can easily be pulled up, and the aboveground parts also stop developing, are grayish green, and gradually turn yellow, and may even cause the whole plant to die.
Prevention and control measures: The seedbed temperature can be raised by heating and other methods; control the amount of watering in the seedbed. When watering, reasonably irrigate with warm water according to the dry and wet conditions of the seedbed soil, and do not irrigate heavily. If root rot occurs, watering should be suspended, ventilation should be timely to remove moisture, evaporation should be increased, or the soil should be loosened for aeration.
3. Cold damage
When seedlings are exposed for a long time to low temperatures above 0 degrees or to temperatures below 0 degrees, the normal damage to the seedlings shows as slow seedling growth, poor root development, dark green or yellowing leaf color, curled and wilted leaves, and even death of the whole plant as if scalded by boiling water.
Prevention and control measures: If the low-temperature damage is not serious, under the condition of reducing direct light, a small amount of water can be sprayed, and the temperature can be gradually raised, which can also help the seedlings resume growth.
4. High-temperature seedling burn
This phenomenon occurs more often in small plastic-film arched sheds. With changes in sunlight, the temperature changes drastically. At noon on a sunny day without ventilation, it can steadily rise above 50 degrees, which causes high-temperature seedling burn. In mild cases, there is water loss and wilting; in severe cases, the leaves have obvious brown scorch spots, and the whole plant may even quickly collapse and die without recovering.
Prevention and control measures: When raising seedlings in early spring, attention should be paid not only to cold protection but also to preventing high-temperature damage, especially for fruit and vegetable seedlings. Even if the seedlings are not burned to death or injured by the heat, as long as the temperature is above 35°C for a relatively long time, flower bud development will be damaged, with a clear impact on normal plant development and yield.
The above is an introduction to prevention and control measures for common physiological diseases at the vegetable seedling stage. We hope it can help you. To learn more related knowledge, please keep following us.