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Occurrence and prevention of vegetable collapse disease
First, the symptoms
After the seed of the vegetable is germinated, the cotyledon and the embryo are rotted, causing rotten species. After the cotyledons are unfolded, the water-stained lesions are formed at the base of the stem of the diseased seed, and then turn into a yellow-brown color, which collapses into a line shape, that is, collapses. The seedlings of the seedlings can not stand upright, and the other appearances of the seedlings are no different from those of the healthy seedlings.
Second, the prevention and treatment method
1, seed bed selection. Try to build on the oysters of the uncultivated seedlings. Do not build on the old seedbed. To build a bed on an old seedbed, you must replace the large field soil with less germs or disinfect the soil. Fertilizer application must be decomposed.
2. Seedling technology. Use modern seedling technology, such as electric hotbed technology, artificial temperature control seedling technology, etc., to maintain the appropriate temperature of the seedbed.
3, bed soil disinfection
(1), formalin disinfection: 2 to 3 weeks before sowing, the bed soil loose, 50 ml of formalin per square meter of seedbed, add water 18 ~ 36 kg (added water is determined by the soil dry and wet) , evenly poured on the seedbed. It is then covered with a plastic film on the bed soil. After 3 to 5 days, the cover is removed and the bed soil is removed. After about 2 weeks, the drug solution is fully evaporated and then seeded.
(2) Disinfection of pentachloronitrobenzene, etc.: Mix 70% of pentachloronitrobenzene with 50% of thiram, and apply 8-10 g per square meter (4-5 g each). Add 20~30 kg of fine soil and mix well. Before sowing, spread 1/3 of the soil evenly on the bed surface to make the soil, then spread the seeds on the soil, and then cover the remaining 2/3 of the soil on the seeds as the cover soil. After covering the soil, the surface of the soil should be sprinkled with water to keep the soil moist. Do not let the soil be too dry to avoid phytotoxicity.
(3), carbendazim or thiophanate disinfection: use 50% carbendazim or 50% thiophanate, 8 ~ 10 grams per square meter, the use of the same method.
(4), disinfection of the original Kekesong powder: use 70% dikesong powder, 500 grams per 667 square meters, plus 20 ~ 25 kg of fine dry soil, used before sowing.
4. Seed treatment. Seeds are immersed in warm water at 48-49 °C for 10-15 minutes before sowing. If seed dressing is carried out with 50% thiram double wettable powder or 65% dasen zinc wettable powder, the dosage is 0.3% of the seed weight.
5, seedbed management seedlings. The bed temperature should be appropriate to reduce low temperature damage. Appropriately increase the number of soil loose soil and promote root growth. Control the proper humidity. In the early stage of emergence, the soil can be sprinkled on the bed for 1 or 2 times to protect the ground and make up the ground cracks. When the humidity of the seedbed is too large, the number of ventilation should be increased when the temperature is high, the moisture of the seedbed should be eliminated, and the humidity of the seedbed should be reduced. When the seedbed is dry and must be watered, it should be done in the morning. Immediately after watering, the plastic film is covered to increase the temperature of the seedbed, and the air is ventilated at a high temperature at noon. The amount of water is measured by the rhizosphere soil of the seedlings. Take all measures to improve the lighting conditions of the seedbed. Promptly expose the insulation cover and extend the time of seeing light. After the emergence of seedlings and time seedlings, seedlings should be divided into seedlings in time to prevent seedlings from being too dense, affecting ventilation and light transmission, resulting in excessive humidity and weak growth of seedlings. When the watering or seedbed humidity is too high, the dry grass ash can be sprinkled several times in the seedbed. Dry grass ash has the functions of moisture absorption and humidity reduction, increasing light absorption capacity, increasing ground temperature, and inhibiting the growth of pathogens. It was found that the diseased seedlings were removed in time and carried to the field for deep burial or burning. Spray 1ppm natural alizarin - Shuofeng 481 liquid once to improve disease resistance.
6, chemical control. After the disease is discovered, the following agents can be used: 75% chlorothalonil wettable powder 600 times solution; 64% antivirus WP WP 500 times solution; 70% mancozeb WP 500 times solution; 70% kekesongyuan Powder 1000 times solution. Choose one of the above agents, or use them alternately, once every 7~10 days, even spray 2~3 times.
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