First, the symptoms can be affected from seedlings to adult plants. The seedling stage occurs at the base and root of the stem. The lesions are brown at the beginning, and are enlarged, prismatic, long or irregular, slightly depressed and large. The lesions are "rusty", reddish brown or dark brown, and the cortex is rotted and ulcerated. The main roots and fibrous roots of the seriously ill plants rot, causing "bone roots". The soybean disease does not infect the roots, which is the main difference. The diseased plant has poor growth in the upper part of the plant, and the diseased seedling is short and thin, and the leaves are light and yellowish. When it is severe, it is dry and dead. In the adult stage, brown spots are produced at the roots of the diseased plants, which are irregular in shape and vary in size. When the disease is severe, the roots are cracked and the lignocellulosic tissue is exposed. The upper part of the affected part is thinner than the healthy plants and less pods. Soybean root rot often occurs in the field as a "pot bottom pit", round or oval. It is different from the "broken strip" caused by the development of insects.
Second, the prevention and treatment methods 1, the rotation should be carried out with grass crops for more than 2 years of rotation.
2, the selection of soybean varieties with mild disease.
3, agricultural measures appropriate late broadcast, control sowing depth, the general sowing depth should not exceed 5cm. Add pb or organic fertilizer. Reasonable cultivating and cultivating soil, implementing deep pine, timely eliminating water accumulation in the field, improving soil ventilation conditions, and controlling underground pests.
4. Seed treatment with 50% Dufu mixture wettable powder, seed dressing at 0.4% of seed amount; seed dressing with 1% of seed amount (2% Ningnanmycin water); 50% Fumi Double wettable powder or 50% carbendazim wettable powder for seed dressing at 0.5% of seed amount; seed dressing with "soybean micro-composite fertilizer" developed by Provincial Academy of Agricultural Plant Protection; 35% with fungicide Dokfu soybean seed dressing seed dressing; spray plant compound nutrient solution at the seedling stage; spray the roots with the fire dragon enemy in the soybean seedling stage, and spray 2 to 3 times at intervals of 7 to 10 days.
Deep groove Ball Bearing is the most representative structure in rolling bearing, which is widely used. In addition to radial load, this kind of bearing can also be loaded with bidirectional axial load. The friction torque is small, and it is most suitable for adjusting rotation, low noise and low vibration. Bearings are widely used in automobile, electrical, instrumentation, construction machinery, agricultural machinery and various professional machinery. This kind of bearing has open and closed deformation structure. 
Deep groove ball bearings consist of an inner and outer ring with a cage containing a complement of precision balls. The standard Conrad-type bearing has a deep-groove construction capable of handling radial and axial loads from either direction in versatile designs that permit relatively high-speed operation.
Deep groove ball bearing is the most representative structure in rolling bearing, which is widely used. In addition to radial load, this kind of bearing can also be loaded with bidirectional axial load. The friction torque is small, and it is most suitable for adjusting rotation, low noise and low vibration. Bearings are widely used in automobile, electrical, instrumentation, construction machinery, agricultural machinery and various professional machinery. This kind of bearing has open and closed deformation structure.
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