Occurrence and control of diseases of solanaceous vegetables at seedling stage

1. Tomato, eggplant, and pepper are sick
1, symptoms. The squatting disease occurs mostly in the seedbed. When the seedlings are unearthed, the leaves are infected, causing water-stained dark spots on the base of the seedlings of the seedlings, and then expanding around the stems, gradually shrinking into thin lines, and the upper part of the seedlings falls down on the ground due to the loss of support ability. . When the seedbed is humid, the white cotton-like fungus line is often densely formed on the surface of the pathogen or its vicinity.

2. Routes of transmission and conditions of disease. The bacterium is overgrowth with the diseased residue in the soil, and can live in rot. When the condition is suitable, the oospores germinate, produce germ tube, directly invade the young shoot, or form a sporangium after the top of the germ tube is swollen. The zoospores are spread to the seedlings by rainwater or irrigation water, and invade from the stems, and the incubation period is 1-2 days. When the humidity is high, the sporangia and zoospores produced on the diseased seedlings are re-infected with the pathogen, which is optimal for 34-36 ° C, but can also grow at a low temperature of 8-9 ° C. In the middle of July, the county has a solanaceous seed bed. Easy to get sick.

Second, tomato, eggplant, pepper blight
1. Symptoms: Seedlings and large seedlings that have just been unearthed can be affected. The base of the stem of the diseased seed became brown, and the diseased part contracted finely, and the stems and leaves succumbed to death; the seedlings wilted during the day and recovered at night. When the lesions circled the stem for a week, the seedlings gradually died, but this is not important to distinguish the disease. feature.

2. Routes of transmission and conditions of disease. The mycelium or sclerotia is overwintered in the soil and can be spoiled in the soil for 2-3 years. The hyphae can directly invade the host and spread through the water flow and the agricultural implement. The pathogen is suitable for development at a temperature of 24 ° C, a maximum of 40-42 ° C, a minimum of 13-15 ° C, and a suitable pH of 3-9.5. The seeding is too dense, the seedlings are not timely, and the temperature is too high to induce the disease.

3. Tomato, eggplant, pepper, and disease prevention and control methods
Spraying 0.2% potassium dihydrogen phosphate and 0.1% calcium chloride at the seedling stage can enhance disease resistance. Seed dressing with 40% seed dressing double or 32% seedling WP with 0.2% seed weight. The seedbed soil treatment can be used alone with 40% seed dressing double powder, or 40% pentachloronitrobenzene mixed with thiram double 1:1, 8 grams per square meter seedbed. At the beginning of the disease, 72.2% Plex water 400 times solution can be used, 2-3 liters per square meter of spray liquid, and 15 times of 15% carbaryl water agent can be selected. When the squatting disease and the blight are mixed, 72.2% Plex water 800 times liquid plus 50% Family double WP 800 times liquid spray, 2-3 liters per square meter, depending on the condition 7-10 days 1 time, continuous control 2-3 times.
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