Causes of Lettuce Root Rot and Detailed Prevention and Control Measures
Lettuce prefers a cool environment, and now is a good season for planting lettuce. However, during the seedling stage of lettuce, many growers have found that lettuce suffers from root rot, causing large numbers of lettuce seedlings to die. So what causes lettuce root rot? How should it be prevented and controlled? Let's take a look together.
1. Symptoms of root rot
When seedlings are raised in low-temperature seasons, root rot is very likely to occur. When the disease develops, no new roots or adventitious roots are produced at all, and the root bark turns rusty brown, gradually rotting and drying up. When the disease reaches a certain degree, the seedlings can easily be pulled out of the soil. In the early stage of the disease, the symptoms are not obvious, and the aboveground stems and leaves grow slowly. The leaves gradually turn yellow-green or milky yellow, and the leaf edges begin to wither and turn yellow, until the entire leaf shrivels and turns yellow. The seedlings do not produce new leaves, and in severe cases the entire plant dies.
2. Causes of root rot
Because the soil temperature is below 12 degrees, the duration is relatively poor, excessive watering, continuous rainy days, and insufficient light and other reasons cause the seedling root system to be in a state of low soil temperature, excessive moisture, and lack of oxygen. The respiratory metabolism of the root system is blocked, normal growth and development cannot occur, and the root system's absorption capacity decreases, causing root rot. In addition, root rot can also occur when the substrate used in soilless cultivation has long-term water accumulation.
3. Prevention and control methods
When preparing the seedbed, ensure that the soil is loose and level, so as to avoid water accumulation on the seedbed surface after watering, and ensure that the seedbed has sufficient light. When sowing, it should be precise and uniform, and the soil covering should not exceed 1 cm. Before sowing, water thoroughly to ensure sufficient bottom water. Throughout the seedling stage, watering should be controlled to avoid excessive moisture on the bed surface, and especially to prevent the soil from being wet and shaded for a long time. 3-5 days before sowing, first cover with plastic film to raise the bed soil temperature, then remove the film before sowing. If sowing is done without waiting for the low temperature to rise, the seeds will germinate slowly. After emergence, ventilate at the appropriate time and in the appropriate amount to strengthen the hardening of the seedlings. When planting at low temperature, water by hole, and do not flood irrigate. Fertilization should be uniform. After root rot occurs, plastic film can be covered to raise the ground temperature, and the soil should be loosened in time to promote the diseased seedlings to produce new roots.
The above is an introduction to the causes of lettuce root rot and prevention and control measures. We hope it can help you. If you want to learn more related knowledge, please stay tuned to us.