First, the disease
1. Symptoms Seedlings can be harmed before they are unearthed, causing seeds, germs or cotyledons to rot. After the seedlings were unearthed, the water-stained yellow-brown lesions on the base of the young stems near the ground spread around the stems, which seemed to be hot, and then the stems collapsed into a line, and the seedlings fell to the ground. After the disease occurs, the cotyledons tend to remain green in the short term, while the root epidermis rots brown. In the high-humidity seedbed or even the rainy weather, only the individual seedlings showed symptoms. After a few days, the diseased plants were rapidly spread around the center, causing large seedlings to collapse. When the air is humid, the white flocculent layer may appear on the surface of the diseased seed or the soil and is different from the blight.
2. Route of transmission and pathogenesis The disease is mainly caused by Pythium fungi. The main factors affecting the occurrence of the disease are soil temperature, humidity, light and management levels.
Excessive temperature of the seedbed, excessive watering, soil temperature below 15 °C, excessive rainy weather, insufficient light, excessive sowing, untimely seedling transplanting, application of contaminated fertilizer, long-term use of the same seedbed soil, etc. may induce the disease or Aggravated. The main route of transmission is rain or running water.
3. Control methods Adopt rapid seedling, soilless seedling or disease-free soil.
Seedbed treatment. 15 to 20 days before sowing, the bed soil is turned flat, 40 ml of 40% formaldehyde (formalin) per square meter, 2 to 4 kg of water, evenly poured on the bed soil, and then covered with film or sack 4 to 5 days, then remove the cover, turn the bed soil 2 to 3 times, 10 to 15 days to plant. Can also be mixed with 50% carbendazim wettable powder and 50% Fumei double wettable powder 1:1, 8 ~ 10 grams per square meter, plus 10 ~ 15 kg of fine soil mix well into a medicinal soil, will be three points when sowing The second herb is sprinkled on the surface of the clam and covered with a third of the soil after sowing.
Seed treatment. Soaking the warm soup can kill the bacteria carried on the seed, and can also play the role of germination and early emergence; for the treatment of the drug, 50% Fumex WP 300 times or 50% carbendazim WP 800 times; or Soak the seeds with 2:1 mixture of 25% metalaxyl WP 1500 times and 65% sensitized zinc WP 1500 times.
Strengthen seedbed management. The seeding density should not be too large, pay attention to the seedlings and seedlings, do a good job of heat preservation, apply enough base fertilizer, and the manure should be fully decomposed. Do not flood the water to avoid excessive humidity in the seedbed. If the humidity of the seedbed is large, and if it is ventilated in time if conditions permit, it is also possible to sprinkle fine soil or grass ash to reduce humidity. It is necessary to remove the diseased seedlings in time to prevent spread.
Chemical control. After the disease was discovered, it was promptly removed and sprayed.
It can be sprayed once every 5 to 8 days with 25% toxic mycorrhizal WP 500-800 times solution, 64% anti-virus 矾M8 WP 500-600 times solution, and 75% chlorothalonil WP 600 times solution. Spray 2 to 3 times.
Second, the blight
1. Symptoms Seedlings can be harmed after they are unearthed, especially in the middle and late stages. The base of the diseased seed became brown, and the diseased part contracted finely, and the stems and leaves succumbed to death. In the early stage of the disease, the seedlings wilted and recovered at night. When the lesions circled the stem for a week, the seedlings gradually died, and the leaves were wilted and could not be restored until they stood upright. The lesions are initially elliptical dark brown, with concentric circles and pale brown spider silk mold, and the formation of sclerotia in the later stage, is another important feature distinguishing from the disease.
2. Route of transmission and pathogenesis The disease is caused by the infection of the nucleus of the nucleus, and the temperature of the pathogen is 24 °C. If the seeding is too dense, the seedlings or the seedlings are not timely, the seedlings are long, the temperature is too high, the ventilation is poor, or the soil moisture is high or low, and the disease is easily induced. Often infested from roots, young stems and wounds.
3. Control method Seedbed treatment. Refer to the disease.
Seed treatment. Seed dressing with 40% of the seed weight of 40%, or seed dressing with 50% thiram. Strengthen seedbed management. Pay attention to improve the ground temperature, scientific ventilation, and prevent high temperature and high humidity in the seedbed.
In the early stage of the disease, spray 50% of the dry WP 800 times solution, 36% thiophanate-methyl suspension 500 times solution, or 70% mancozeb WP 600 times solution or 5% Jinggangmycin water 1500 times the solution. When the disease is mixed and the blight is mixed, it can be sprayed with 50% Fumei double wettable powder 800 times, 2 to 3 liters per square meter, once every 7 to 10 days, and continuously controlled 2 to 3 times.
Third, the root
1. Symptoms Young roots (no seedling stage or post-planting) do not produce new roots, the surface of the young roots is rust brown and then rot, causing the upper part of the leaves to turn yellow. Severe wilting and death, extremely easy to pull up.
2. Causes caused by low temperature (ground temperature below 12 ° C) for a long duration, excessive watering or even rainy weather, insufficient light, etc.
3. Control method The surface should be flat and the flooding is strictly prohibited. Even the rainy days should be ventilated and ventilated in time.
Breeding with a solar energy greenhouse or a hot wire. Strengthen the temperature management of the seedbed and control the temperature of the seedbed above 15 °C. After a slight rooting occurs, it is necessary to loosen the soil in time and raise the ground temperature. After the new root grows, it will be transferred to normal management.
1. Symptoms Seedlings can be harmed before they are unearthed, causing seeds, germs or cotyledons to rot. After the seedlings were unearthed, the water-stained yellow-brown lesions on the base of the young stems near the ground spread around the stems, which seemed to be hot, and then the stems collapsed into a line, and the seedlings fell to the ground. After the disease occurs, the cotyledons tend to remain green in the short term, while the root epidermis rots brown. In the high-humidity seedbed or even the rainy weather, only the individual seedlings showed symptoms. After a few days, the diseased plants were rapidly spread around the center, causing large seedlings to collapse. When the air is humid, the white flocculent layer may appear on the surface of the diseased seed or the soil and is different from the blight.
2. Route of transmission and pathogenesis The disease is mainly caused by Pythium fungi. The main factors affecting the occurrence of the disease are soil temperature, humidity, light and management levels.
Excessive temperature of the seedbed, excessive watering, soil temperature below 15 °C, excessive rainy weather, insufficient light, excessive sowing, untimely seedling transplanting, application of contaminated fertilizer, long-term use of the same seedbed soil, etc. may induce the disease or Aggravated. The main route of transmission is rain or running water.
3. Control methods Adopt rapid seedling, soilless seedling or disease-free soil.
Seedbed treatment. 15 to 20 days before sowing, the bed soil is turned flat, 40 ml of 40% formaldehyde (formalin) per square meter, 2 to 4 kg of water, evenly poured on the bed soil, and then covered with film or sack 4 to 5 days, then remove the cover, turn the bed soil 2 to 3 times, 10 to 15 days to plant. Can also be mixed with 50% carbendazim wettable powder and 50% Fumei double wettable powder 1:1, 8 ~ 10 grams per square meter, plus 10 ~ 15 kg of fine soil mix well into a medicinal soil, will be three points when sowing The second herb is sprinkled on the surface of the clam and covered with a third of the soil after sowing.
Seed treatment. Soaking the warm soup can kill the bacteria carried on the seed, and can also play the role of germination and early emergence; for the treatment of the drug, 50% Fumex WP 300 times or 50% carbendazim WP 800 times; or Soak the seeds with 2:1 mixture of 25% metalaxyl WP 1500 times and 65% sensitized zinc WP 1500 times.
Strengthen seedbed management. The seeding density should not be too large, pay attention to the seedlings and seedlings, do a good job of heat preservation, apply enough base fertilizer, and the manure should be fully decomposed. Do not flood the water to avoid excessive humidity in the seedbed. If the humidity of the seedbed is large, and if it is ventilated in time if conditions permit, it is also possible to sprinkle fine soil or grass ash to reduce humidity. It is necessary to remove the diseased seedlings in time to prevent spread.
Chemical control. After the disease was discovered, it was promptly removed and sprayed.
It can be sprayed once every 5 to 8 days with 25% toxic mycorrhizal WP 500-800 times solution, 64% anti-virus 矾M8 WP 500-600 times solution, and 75% chlorothalonil WP 600 times solution. Spray 2 to 3 times.
Second, the blight
1. Symptoms Seedlings can be harmed after they are unearthed, especially in the middle and late stages. The base of the diseased seed became brown, and the diseased part contracted finely, and the stems and leaves succumbed to death. In the early stage of the disease, the seedlings wilted and recovered at night. When the lesions circled the stem for a week, the seedlings gradually died, and the leaves were wilted and could not be restored until they stood upright. The lesions are initially elliptical dark brown, with concentric circles and pale brown spider silk mold, and the formation of sclerotia in the later stage, is another important feature distinguishing from the disease.
2. Route of transmission and pathogenesis The disease is caused by the infection of the nucleus of the nucleus, and the temperature of the pathogen is 24 °C. If the seeding is too dense, the seedlings or the seedlings are not timely, the seedlings are long, the temperature is too high, the ventilation is poor, or the soil moisture is high or low, and the disease is easily induced. Often infested from roots, young stems and wounds.
3. Control method Seedbed treatment. Refer to the disease.
Seed treatment. Seed dressing with 40% of the seed weight of 40%, or seed dressing with 50% thiram. Strengthen seedbed management. Pay attention to improve the ground temperature, scientific ventilation, and prevent high temperature and high humidity in the seedbed.
In the early stage of the disease, spray 50% of the dry WP 800 times solution, 36% thiophanate-methyl suspension 500 times solution, or 70% mancozeb WP 600 times solution or 5% Jinggangmycin water 1500 times the solution. When the disease is mixed and the blight is mixed, it can be sprayed with 50% Fumei double wettable powder 800 times, 2 to 3 liters per square meter, once every 7 to 10 days, and continuously controlled 2 to 3 times.
Third, the root
1. Symptoms Young roots (no seedling stage or post-planting) do not produce new roots, the surface of the young roots is rust brown and then rot, causing the upper part of the leaves to turn yellow. Severe wilting and death, extremely easy to pull up.
2. Causes caused by low temperature (ground temperature below 12 ° C) for a long duration, excessive watering or even rainy weather, insufficient light, etc.
3. Control method The surface should be flat and the flooding is strictly prohibited. Even the rainy days should be ventilated and ventilated in time.
Breeding with a solar energy greenhouse or a hot wire. Strengthen the temperature management of the seedbed and control the temperature of the seedbed above 15 °C. After a slight rooting occurs, it is necessary to loosen the soil in time and raise the ground temperature. After the new root grows, it will be transferred to normal management.
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