Diseases of winter vegetable seedlings mainly include damping-off disease, blight and roots.
The key points of disease identification were the unripe leaves of the seedlings after the unearthed seedlings. The bases of the stems were infiltrated with fine lines and collapsed to lie on the ground. When the humidity of the seedbed is large, white flocculent mycelium is often densely produced on the surface of the diseased seedling or its vicinity, which is different from blight.
After emergence of stem blight, seedling stem bases browned and contracted, stems and leaves wilted and died; slightly larger seedlings wilted during the day, recovered at night, and did not show collapse after death. The diseased area with concentric ring pattern and light brown spider silk mold is an important feature of this disease that is different from damping-off disease.
The root cause is mainly because the ground temperature is lower than 12°C, and the duration is longer. Together with the excessive watering or the rainy weather, the sprouts will appear wilt and the stubborn roots will occur for a long time. The roots showed no new roots or adventitious roots. The root bark was rust and rot. It was easy to pull up. The leaves on the shoots were dry and coking. In severe cases, it was dry and patchy.
Second, control methods Agricultural control (1) water management: seedlings should be controlled as much as possible watering, especially in the evening watering easily lead to high humidity, watering must be selected to spray in sunny days, flood irrigation should not be flooded. (2) Temperature and humidity control: When the temperature is low, cover the film. When the temperature is lower than 0°C, cover the straw curtain and pay attention to the early cover. The seedbed should be ventilated and dehumidified in a timely manner, even when it is cloudy, it must be properly ventilated and ventilated.
Chemicals can be used to prevent and treat damping-off disease DuPont easy to maintain water dispersible granules 800-1000 times, 70% of enemy powder powder 1000 times, 50% carbendazim powder 500 times, 58% metalaxyl manganese zinc powder 500 times or 72.2 % Propolis water spray 600 times; control blight can be used 70% of the enemy's powder 1000 times, 70% thiophanate powder 1000 times spray; two diseases can be used when mixing 50% omeprazole WP 800 times plus 72.2% Precise 600 times liquid spray. The above medicaments are used once every 7-10 days, depending on the condition of the disease and prevent 2-3 times.
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