(1) Damping-off disease
Damping-off is a common seedling disease of Solanaceae crops. It mainly harms seedlings or causes rotten seeds. After the seedlings are unearthed, the disease occurs near the ground of the young stems. Shrink, rot, and the seedlings will fall down. The fallen seedlings are still green in a short period of time, and the diseased part is densely covered with white woolly mold when it is wet. If the soil temperature is lower than 15°C, the humidity is too high, and the light is insufficient, the growth of the seedlings will be weak, especially in severe weather with continuous cloudy, continuous rain, and continuous snow.
The disease is a fungal disease caused by the infection of Pythium melons and fruits. The pathogen can rot in the soil for a long time, survive the winter in the diseased plant residue and the soil, and later harm the seedlings in the seedbed. The pathogen is spread by soil, but also by seed carrier.
(2) Solanaceous Vegetable Seedling Blight
Seedlings infected with blight were wilted during the day, recovered at night, and withered and died after a few days. The young stems close to the ground turn dark brown, gradually turn dark brown, and then shrink and become thinner, causing the seedlings to fall. Indistinct light brown arachnoid fungus was born on the diseased part.
The disease is a soil-borne fungal disease caused by the infection of Rhizoctonia solani. The hazel mold on the diseased part is the mycelium of the pathogen. The mycelium or sclerotia of the pathogen can live for many years on the residue of the diseased plant and other organic matter in the soil, and the bacteria in the bed soil will harm the seedlings. The temperature is 15-21°C, especially when it is above 18°C. Warm and humid, too densely planted, and too much watering will cause the bed to be stuffy and humid, which is not conducive to the growth of seedlings, and is prone to disease.
Prevention methods:
①Choose a place with high terrain and good drainage as the seedbed. The fertilizer should be fully decomposed, and the sowing should be even and not too dense.
②Choose germ-free soil as seedbed soil. The old bed soil can only be used after being sterilized by chemicals. For seedbed disinfection, use 6-8 grams of mixed powder equal to 70% pentachloronitrobenzene powder and 50% thiram wettable powder (or 65% zinc zinc wettable powder) per square meter; or use pentachloronitrobenzene or 6-8 grams of 50% carbendazim, add about 12.5 kg of semi-dry fine soil and mix to make medicine soil. Before sowing, sprinkle one-third of the medicine soil on the seedbed as cushion soil, then sow, and then use the remaining The medicinal soil is used as a cover and has a good preventive effect.
③ Pay attention to seed treatment and seedbed management, soak the seeds in warm water at 55°C before sowing, or treat them with chemicals, and then germinate and sow. Control the temperature and humidity of the seedbed, and the amount of watering should not be too much. And pay attention to ventilation to prevent the seedlings from freezing. If diseased seedlings are found, they shall be pulled out immediately, burned or buried deeply.
④ chemical control. In the early stage of the disease, use 1 kg of lime and 10 kg of plant ash to mix and spread, or spray copper ammonium mixture (2 parts of copper sulfate, 11 parts of ammonium bicarbonate, grind into powder and mix, after 24 hours of airtightness, add 400 parts per kg of mixed powder. kg of water), or spray with 500 times liquid of 70% mancozeb wettable powder, spray once every 7-10 days, and spray 2-3 times continuously.
Expert tips: Seedling disease should be based on strengthening the control of seedling raising process, do a good job of disinfection of seeds and seedling soil, adjust the temperature, humidity and time of seedling raising, etc.
