The city of Suihua in Heilongjiang Province is the main soybean producing area. It has planted nearly 300,000 hectares of soybeans all year round. In recent years, the incidence of soybean mosaic disease has been increasing year by year. Most of the land masses have occurred. The incidence of diseased plants in the field is generally about 4.8%, and the severity is more than 20%. The brown (black) grain rate of soybean grain Above 10%, the soybean yield will decline and the quality will decline. We have adopted a comprehensive selection of seeds, combined with timely removal of diseased strains, using highly effective and low-toxic, low-residue insecticides to control aphids, pharmaceutical prevention and other comprehensive supporting technical measures, and achieved good control effects. The control effect is over 90%. . First, the cause of the disease 1. Seed virus pathogens mosaic virus, viral particles are linear. The primary infestation source of soybean mosaic disease is mainly the infected seeds. Plants with infected seeds become the source of reinfection in the field, and the soybean mosaic virus is susceptible to infection. Virus-infected soybean seeds have more brown (black) granules, and the seed brown (black) granuloma rate is about 10%. 2. Aphid-transmitted soybean mosaic virus vector insects are mainly soybean meal. High temperature, low rainfall, high concentration of soybean body fluids, nutrient-rich breeding of aphids. The larger the number of locusts and the earlier they appear, the more the early disease strains and the heavier the occurrence of mosaic disease. In recent years, the occurrence of soybean aphids has been relatively large, providing a medium for the occurrence of soybean mosaic virus. From 2000 to 2003, the number of aphids infested was nearly 10,000 heads per 100 soybeans, and the percentage of aphids was over 90%. . Second, the onset of symptoms 1, soybean leaf mosaic disease leaf symptoms were typical mosaic symptoms on the leaves, generally in the tender leaves on the symptoms of leaf mosaics, and in the old leaves are often not obvious. There are three kinds of common mosaic symptoms: one is heavy mosaic type, the diseased leaves are yellow and green mottled, severely crumpled, brown veins are curved, and the leaves are blister-shaped, dark green, and the leaves of the entire leaf are curled backwards. Vein necrosis occurs in the late stage and the plants are dwarfed. The second type is the wrinkled mosaic type. The diseased leaves are yellow and green and the leaves are shriveled. The leaves are blister-like along the veins. The curling down of the leaf margins often causes the leaves to shrink and show twists and turns, and the plants are dwarfed. Less knots. The third type is light mosaic type, and the leaf growth is basically normal. A slight yellowish mottle is observed with the naked eye. The diseased leaves are picked off by sunlight to see the mottled yellow-green phase. Most disease-resistant varieties or late susceptible plants showed this symptom. 2. The symptoms of soybean seedlings usually appear on the true leaves of the Mingmai phenomenon, and soon become mosaics, the internodes of the diseased plants are shortened, and the plants are dwarfed. The dwarfing of seed-borne plants was heavier, while the dwarfing phenomenon was not evident in plants infected with aphids at later stages. 3. Symptoms of lesions on soybean grains often start with radium or irregular brown or black markings from the umbilicus. The presence and severity of markings are related to the period of disease, and the seeds of the diseased plants with infected seeds grow. Obviously, seed propagation has a high rate of poisoning, and plants infected by aphids at the later stage are susceptible to disease, especially after flowering, and the spots on the seeds are often not obvious. However, whether the seeds are poisoned or not is not entirely determined by the presence or absence of markings. Unspotted seeds are not necessarily poisonous. Third, prevention and control measures 1, select soybean seeds before sowing should be strictly selected seeds, artificial carefully selected sick soybean grains, remove brown (black) grain, to minimize the initial infestation. 2. The incidence of disease prevention and control of soybean mosaic disease is closely related to the occurrence of aphids and the emergence of aphid in the morning and evening. Therefore, investigation and prediction of insect pests are carried out, and pesticides are promptly sprayed to eradicate cockroaches and eliminate aphids at the point and stage. , is the key to control of soybean mosaic disease. Pesticides for control of aphids include: 10% imidacloprid per hectare (Da Gong Chen, once-through, fluttering, decanting, etc.) WP WP 300 to 450 gram, 3% MOBIANG EO 450 mL, 450 kg water spray ; Or per hectare with 2.5% green Kung Fu EC 600 ml, 20% Huifeng Ke EC 300 ~ 450 ml, 450 kg of water evenly sprayed. 3, drug prevention disease in soybean seedlings, combined with spade shovel timely removal of diseased plants. At the same time, before the onset or early onset of the disease, spraying and preventing virus disease, with 2% bacteriocins, 1.7-2.25 kilograms per hectare, 450 kilograms of water spray, to achieve uniform spray, no leakage, continuous spraying 2 Each time, the interval is 7 to 10 days; or use 20% poisonous A wettable powder 900 grams per hectare, spray 450 kg water, evenly spray, spray once every 7 to 10 days, and spray 3 times. In addition, in July-August, it is also possible to combine the use of insecticides for the control of aphids to control viral diseases.
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