Disease at the seedling stage is a general term for a variety of physiological diseases and invasive diseases during rice nursery. It is also called gill disease. Physiological rotting refers to bad environmental conditions caused by rotten species, rotten buds, black roots, blue and yellow withered dead seedlings and other symptoms; infestation rotten roach refers to cotton rot disease and damping-off caused by dead bacterial disease symptoms. Northern rice growing areas are often attacked by low temperature and cold weather. The annual incidence of gill disease is between 10% and 23%. Symptoms Symptoms 1. Physiological rot: 1. Rotten seed, which means that the seed does not germinate, that is to say, rot; 2. Decayed shoot, which means that just sprouted buds are stunted and curled like fish hooks. They die when they are not rooted, or they fall into the mud. Decayed to death, or the formation of rafting; 3. Black root, refers to the root of the seedlings black rot, the leaves gradually withered; 4 blue and dry, refers to the seedlings green not yellow dead suddenly, the base is not rot, the seedlings are not easy to pull up; 5. Yellow Withered, it means that the seedlings slowly turn brown and yellow and die, the roots rot, and the sickness is easy to pull up. Second, the infestation of rotten roe: 1. Floccile rot disease, aquatic seedlings sow 5 to 6 days can be planted, seedlings about 3 cm high weight, damage to young roots and shoots. A small amount of milky gelatinous material appeared at the cracks of the shells or at the base of the buds, which gradually grew out of radial white flocculent hyphae, which gradually became rust-colored, green-brown or brown; the seeds could not germinate when rotted, or the roots of the diseased seedlings rotted and died. The disease occurred from spot to film, and when severe, it died. Bacterial blight, wet nursery, dry nursery and film nursery seedlings are more common. The symptoms are as follows: (1) bud rot. The young shoots of the bud before emergence are browned, twisted, rotted and died, and a white fungus layer emerged later; (2) Needle rot, seedlings from the needles to the yellow leaves at the 2 leaf stage, browning at the base, sometimes brown spots on the leaf sheaths, moldy shoots at the base of the stems, the seedlings are easy to pull off; (3) yellow wither, 1 seedlings with 1 leaf To the third to fourth leaf stage, the lower leaves begin to yellow and wilting, the root hairs are scarce, and the bases turn brown and soft rot. (4) Bacterial, mostly occurring before and after the three-leaf stage, the leaves of the seedlings or the upper leaves are rolled into willow leaves. Grayish gray, few root hairs, brownish soft rot at the base of the late stage, easy to cluster. Pathogens and occurrence of physiological rot are mostly due to poor seed quality, uneven heat and cold during germination, poor sowing quality, excessive water storage, lack of oxygen and suffocation, as well as cold or post-cold temperature changes at seedling stage. Heigen is due to excessive fertilizer, deep water storage, and large amounts of hydrogen sulfide, iron sulfide and other reducing substances poisoning seedlings. Bacillus spp. of infective gills is mainly caused by the infection of cotton molds, fungal infections such as Pythium spp., and blight is mainly caused by Fusarium spp. and Rhizoctonia solani. The pathogenic bacteria can live in the soil for a long period of time, and winterize with mycelia, oospore, sclerotia in the soil or in the diseased body, and spread by water flow and airflow; Rhizoctonia with mycelium and sclerotia in the diseased body and soil Overwintering, spread by running water, mainly through wounds, young tissue invasion. Prevention and control measures Prevention and treatment of rice seedling disease should adopt comprehensive measures to improve seedlings, improve seed quality and germination techniques, strengthen management of farmland, and supplement with chemical control. According to local conditions, plastic film seedlings, floppy disk seedlings and dry nursery seedlings are used. Water seedlings are not recommended. Putian chose to shelter the sun, flat terrain, medium fertility, convenient irrigation and drainage plots. Keep seed, seed storage, drying, and seed selection to increase seed germination rate. Seed soaking in warm water (55°C for 10 minutes) or soaking with chemicals (50% carbendazim 800 times for 3 days). During germination, the temperature is stable at more than 10°C to prevent over- or under-concentration, ensure that the buds are uniform, homogeneous and strong, and strengthen the cold resistance of the seedlings. Strengthen seedling management, fine land preparation, ensure bed leveling, bed temperature and permeability; choose temperature when stable above 10°C; sow scientifically, use water temperature to protect seedlings; apply reasonable fertilizer, pay attention to NPK combination, increase organic application Fertilizer, avoid nitrogen, enhance seedling disease resistance. Chemical control, early onset of drug use, sprinkled 75% of the enemy's 1000 times liquid, or 50% of Johnson's ammonium 800 times, 5.5% soaking spirit 3000 ~ 5000 times, 58% metalaxyl manganese zinc 1500 times, 2 to 3 kg per square meter. Body Building Food,Dried Orange Peel Powder,Honeysuckle Flower,Frozen Orange Peel Lixian Spring Pharmaceutical Co., Ltd. , https://www.lxctyy.com