Disease death
Seedlings mainly due to seedbed soil before bed, nutrition soil is not disinfected or disinfected thoroughly, did not spray in time after emergence, and improper management of the seedbed temperature, humidity, etc., causing damping-off, blight occurs. Control measures: First, per cubic meter of seedlings with 50% carbendazim 8 ~ 10 grams or 1 gram of Greenhenge, mixed with the appropriate amount of fine dry soil after spreading in the flour surface, soil and mix well after sowing. The second is that 75% of the seedlings are unearthed and sprayed with 50% carbendazim to sterilize and prevent disease by 500 times. Afterwards, spray once every 7 to 10 days to timely cover the straw curtain and ventilation to prevent humidity and temperature in the seedbed. Excessive inducement of disease.
Pest killing
When a large number of underground pests such as cockroaches, cockroaches and cockroaches occur in the seedbed, they cause harm and cause dead seedlings. Prevention and control measures: 80% of dichlorvos emulsifiable concentrate 1000 times watering seedbed bed soil surface, can prevent earthworms; with 80% dichlorvos emulsifiable concentrate 100 times or 50% phoxim EC 50 times mixed crushed and fried bean cake, wheat bran and other systems Poison baits can be sprinkled on the soil surface of the seedbed to kill crickets. The use of 50% phoxim EC 1000 times solution or 48% Le Siben EC 2000x solution to water the soil surface of the nursery can effectively control the damaging effects.
Drug Killing Seedlings
When the seedbed soil is disinfected, the dosage is too large, the bed soil is too dry after sowing, and the spraying concentration after emergence is too high, which can easily cause drug-killed seedlings. Preventive measures: Do not use excessive doses of seedbed soil disinfection. After the treatment of the seedbed, it is necessary to maintain a humidity, but the amount of water each time should not be too much to avoid excessive moisture seedbed. Once roots occur, they must be promptly ventilated and drained to promote evaporation. On rainy days, dry fine soil or dry wood ash can be spread on the seedbed.
Fertilizer killing
Seed soil mixed with uncooked organic fertilizer or mixed fertilizer caused by burning root dead seedlings. Prevention and control measures: The organic fertilizer must be fully decomposed and evenly mixed with the seedbed soil. When sub-seedling, the soil should be compacted and leveled, and the nutrient should be thoroughly drenched.
Frozen seedlings
At the time of cold current and low temperature, cold measures were not taken in time, resulting in seedlings freezing and death, or improper timing of seedlings. The seed bed soil temperature was too low, and seedlings could not take root and cause dead seedlings after being divided into seedbeds. Prevention and control measures: First, during the seedling raising period, attention should be paid to changes in the weather. In the event of cold currents and low temperatures, the cover should be increased in time. The second is the use of artificial temperature control seedlings, such as electric hotbed nursery, seedlings. The third is to reasonably increase light, promote photosynthesis and accumulation of nutrients, properly control watering, reasonably increase phosphate fertilizer, potash fertilizer, etc., to improve seedbed soil temperature, ensure seedling temperature requirements, and improve cold resistance.
Air dried dead
The seedlings that have not been ventilated for a long period of time are in a relatively high-humidity space. When the seedbed is ventilated, the seedlings that have not been ventilated after the seedlings are air-dried are kept in a relatively high-humidity space for a long time. When the seedbed is ventilated, the cold air directly convects, or suddenly Uncovering the membranes and blowing the covers off with windy winds can cause the hot and cold air inside and outside the seedbed to change too frequently. The sudden drop in air temperature and humidity causes delicate leaves to lose water too much and cause wilting. If wilting is too long, If the leaves cannot be restored, they will eventually become dry and dry. This phenomenon is called air drying. Prevention and control measures: When ventilating seedbeds, they should be ventilated on the side of sheltered winds. The amount of ventilation should be from small to large, so that the seedlings have a process of adaptation, windy weather, pay attention to the pressure of the cover, and prevent the wind from blowing.
Improper lifting caused dead seedlings
When the seedlings are seeded too often, the seedlings lose too much water at one time, and the seedlings lose water too much. It is not easy to recover and die after seedling separation. The seedlings develop poorly before the seedlings, and the root system is less; the seedlings are too late, causing the roots to be damaged and absorbed. Ability to die and die. Preventive measures: Do not overshoot the roots when lifting, and bring more soil. Remove the seedlings with a damp cloth to prevent excessive water loss. In the process of raising seedlings, the seedlings with few roots, broken leaves, sensible and deformed seeds should be removed; the seedlings should not be large enough to promote the survival rate. Usually the first time the seedlings were divided, when the seedlings of the eggplant were in two leaves, the seedlings of the cabbage were in one leaf and the seedlings of the cucumber were before the cotyledon was unfolded. Sub-seedlings should be selected for sunny days. If the greenhouse is strong and the temperature is high, a straw or shaded roof can be placed over a small shed in the greenhouse to prevent direct sunlight from reaching the seedlings that have just been divided. It caused water loss and wilting, and severely killed dead trees.
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