Common infectious diseases of seedlings include damping-off, blast, anthracnose, and leaf spot. This kind of disease occurs quickly and infects each other, often resulting in lack of seedlings and ridges, so attention should be paid to prevention. Cultivation and disease prevention adhere to the rotation system, do not continuously cultivate the same kind of seedlings in the same nursery, and do not use low-lying land prone to water as a nursery, and the nursery must have corresponding drainage and irrigation facilities. Fine soil preparation, timely sowing, pay attention to the depth of sowing, cover the soil is not too thick, so that the seeds can quickly germinate and seedlings can enhance the resistance of seedlings. Increase the use of decomposed organic fertilizers to meet the requirements of seedlings for various nutrients and make the seedlings grow robustly.
Seed disinfection
Before sowing, select seeds and eliminate weak seeds, because weak seeds have a low germination rate and are often the initial source of infection. Spray the seeds with 0.5% formalin solution, mix well, cover the pile and simmer for 2 hours, then spread out, and then plant the seeds after the formalin gas has run out. Or pre-wet the seeds in cold water for 4-6 hours, then soak them in warm water at 49-50°C for 10 minutes, take them out and dry them before sowing.
Soil treatment
Harrow the soil 2 to 3 weeks before sowing, use 40 ml of formalin per square meter for 1 to 3 kg of water (the amount of water added depends on the soil moisture), cover with a film for 4 to 5 days after watering, and remove the film. After about 2 weeks, wait until the volatilization of the medicine is finished before sowing, or use 50% carbendazim wettable powder or 10% thiophanate methyl or 50% thiram or 70% trichloronitrobenzene and other fungicides, use the medicine per square meter 8-10 grams, add 10-15 kilograms of dry fine soil, and mix into medicinal soil. Before sowing, evenly spread one third of the medicinal soil as a bedding soil. After sowing, put the remaining two-thirds of the medicinal soil As cover soil, and keep the soil moist.
Pharmacy treatment
For root diseases, if a few diseased plants are found in the nursery, they can be disinfected by spraying copper ammonia mixture after pulling them out. The formula is: 2 parts of copper sulfate, 11 parts of ammonium carbonate or 2 parts of copper sulfate, 15 parts of ammonium sulfate, 4 parts of slaked lime, fully mixed and sealed for 24 hours. When using, take 1 part of medicine and 400 parts of water to spray, and spray again after 7-10 days. When the soil surface humidity is too high after spraying, you can sprinkle grass and wood ash to reduce the humidity. For above-ground diseases such as leaf spot, 1% Bordeaux mixture, 50% Desenium, Desenzinc and other fungicides can be sprayed, and spray once every 7-10 days until the disease is controlled. Taking cherry seedlings as an example, root necrosis of cherry seedlings may be caused by wilt disease and rhizome rot. Blight disease can be controlled by spraying methyl trocar, chlorothalonil, etc.; rot disease can be controlled by thiophanate-methyl or carbendazim.