What are the control measures for common physiological diseases of vegetable seedlings?
Physiological diseases often occur during vegetable seedling raising. Physiological diseases differ from infectious diseases both in manifestation and in control. So what are the common physiological diseases of vegetable seedling raising? How should they be controlled? Let's take a look together with the editor.
1. Root burn
Because too much nitrogen fertilizer is applied, and the seedbed soil is dry, applying undecomposed organic fertilizer causes damage to the seedling root system. It generally shows yellow root tips, few and broken fibrous roots, and no new roots, but no fibrous roots, the aboveground leaves are small, the leaves are wrinkled, the leaf color is dark green, and the edges are scorched yellow. In severe cases, it causes the seedlings to die in patches.
Control measures: During the vegetable seedling stage, chemical fertilizer should not be applied too much and should be applied evenly. Use decomposed organic fertilizer as much as possible. When root burn occurs, water appropriately more to reduce the fertilizer concentration in the seedbed soil, or replace the soil and transplant. This can very well address the fertilizer root burn phenomenon.
2. Root rot
Root rot is caused by excessive saturation of soil moisture in the seedbed. When soil moisture is relatively high, air is lacking, and it is also caused by long-term low temperature and insufficient light. It mainly shows root rot, and the seedlings can be easily pulled up. The aboveground part also stops developing, is also gray-green, and gradually turns yellow, and may even cause the whole plant to die.
Control measures: The seedbed temperature can be raised through methods such as heating, and the amount of watering in the seedbed should be controlled. When watering, warm water should be irrigated reasonably according to the dry and wet conditions of the seedbed soil, and flooding irrigation is not suitable. If root rot occurs, watering should be paused, ventilation should be carried out in time 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 temperatures below 0 degrees, the normal damage to the seedlings shows slow seedling growth, poor root development, dark green or yellowing leaf color, curled and wilted leaves, and even the whole plant dying as if scalded by boiling water.
Control measures: If the damage caused by low temperature 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 allow the seedlings to resume growth.
4. High-temperature seedling burn
This phenomenon occurs more often in small plastic-film arched sheds. With sunlight exposure, the temperature changes drastically. At noon on a sunny day, without ventilation, it can steadily rise above 50 degrees. This causes high-temperature seedling burn. In mild cases, water loss and wilting occur; in severe cases, the leaves have obvious brown scorch spots, and even the whole plant quickly collapses and dies without recovery.
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 heat, as long as the temperature is above 35°C for a relatively long time, flower bud development will be damaged, which has a clear impact on normal plant development and yield.
The above is an introduction to the control measures for common physiological diseases of vegetable seedlings. I hope it can help you. To learn more related knowledge, please follow us.