symptom
The growth of the seedlings is very slow, the main roots and fibrous roots on the roots do not produce new roots, the root skin is rusty brown and slowly rots, the growth of stems and leaves is inhibited, the diseased plants wilt during the day, dry up and die after a long time, and the roots of diseased seedlings are easy to pull out .
Etiology
The main reason is that the ground temperature is below 10°C for a long time and the soil humidity is high. In the early spring seedling stage, there are many rainy and snowy weather, the temperature of the seedbed cannot rise for a long time, and the humidity is high; after planting, there are many rainy days, the temperature continues to be low and the amount of watering is large, or the terrain is low-lying and the soil is hardened. Low temperature, high humidity, and low light at the seedling stage are the main causes of root retting.
Prevention method
① Prevention and treatment of root retting at seedling stage. Do a good job of heat preservation in the early stage to prevent cold wind and low temperature invasion. The management of the grass thatch should be uncovered late and covered early. After the seedlings emerge, they should be ventilated in time to reduce the humidity of the seedbed, promote the growth of celery seedlings and strengthen them, and improve the adaptability to low temperature. ability. If the humidity of the seedbed is high, plant ash can be sprinkled to reduce humidity. In case of freezing, rainy and snowy weather, the covering should be thickened.
② Try to lower the humidity and increase the temperature after retting the roots, especially the ground temperature. In areas with a lot of rain, it is recommended to plant in deep furrows and high borders, which is not only conducive to drainage after heavy rains, but also enhances soil air permeability.
③ Expose the soil to the sun before planting the next stubble, and deeply turn the sun-dried soil.
④ The roots of celery appear during the growth period, so pour a small amount of water. Arrange the watering time at 9 o'clock in the morning, combined with cultivating and loosening the soil, to improve air permeability. It can also be poured with 1000 times liquid or 1000 times liquid of chitin with balanced water-soluble fertilizer of Helipu.
