October is the beginning of the season for sowing of eggplant vegetables in winter, and it is at this time that the damping-off occurs in the vegetable seedlings. The common symptoms of damping-off are rotten, dead, and tripping. Rotten seed is the seed has not yet germinated, it has been infected by bacteria and rot; dead seedling is the seed germination to extract the seedlings of the embryo stalk or cotyledon, before it has not yet been unearthed before the death of bacteria suffered death; plucked seedlings unearthed, the real leaf has not yet Before the unfolding, it was infected by bacteria, resulting in water-stained dark spots at the base of the young stems. Then they spread around the stems and gradually collapsed into thin lines. The shoots of the seedlings fell to the ground due to their loss of supporting ability. When the humidity of the seedbed is high, white cotton flocculent mycelium is often densely formed on the diseased seedlings or near the bed. Different from blight.
Germs can also grow at low temperatures of 8-9°C. The pathogen is suitable for the temperature 15-16°C, and the temperature is higher than 30°C. The suitable temperature is 10°C. The low temperature is unfavorable to the host's growth, but the bacteria can still be active, especially the low temperature and high humidity conditions during the nursery period are conducive to the disease. When the seedling cotyledon nutrient is basically used up, the new root is not yet solid before the disease period. At this time, the true leaves have not been extracted, the carbohydrates cannot be rapidly increased, the disease resistance is weak, and in case of rain, snow, cloudy or cold currents, the ground temperature is low, the photosynthesis is weak, the respiration of the melon shoots is enhanced, and the consumption is increased, resulting in young stems Cell elongation, thinning of the cell wall, invasion of pathogens, therefore, the disease occurs mainly in seedlings growing 1-2 true leaves, 3 true leaves, less incidence. The result is a period of continuous rain and rain, and the fruit is susceptible to more serious losses.
Breakdown prevention and control points: 1, bed soil disinfection, bed soil with disease-free new soil, such as the use of old garden soil, there may be bacteria, bed soil soil disinfection should be carried out. Method: Apply 25% metalaxyl wettable powder 9g + 70% mancozeb WP 1g per square meter seedbed and mix 4-5kg fine soil. Before the application, the bottom water of the seedbed is laid well, and once it is thoroughly drenched, generally 17-20 centimeters deep. After the water infiltrate, take 1 / 3 of the well-mixed medicinal soil and sprinkle it on the surface. Then sow the rest 2 /3 Pharmaceutics cover the seed, that is, overlying the lower mat. If the cover soil is not thick enough, it can be used to make up for the suitable thickness so that the seed is caught in the middle of the soil and the control effect is obvious. 2. Strengthen the seedbed management, choose the land with high topography, low groundwater level and well-drained water, make the seedbeds before the sowing, and try not to water the seedlings after emergence. If watering is necessary, it must be done on a sunny day. It is not suitable for flood irrigation. . 3, nursery seedlings (bed) timely release of wind, humidity, even if the cloudy days should also be appropriate timely release of air humidity, prevent seedlings growers infected. 4, at the beginning of the onset of spraying 95% badew spirit (Green Hunt No. 1) 450 times, or 77% of Dunning 600-700 times spray.
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