Soybean is an annual leguminous herb. Its seeds are also known as soy beans, and they are divided into granular soybeans and vegetable soybeans. Because of its high nutritional value, it is known as "the king of beans, the meat of Tanaka, the green milk," and is the most respected food among hundreds of natural foods.
1, soybean virus disease
(1) Type:
Light mosaic type: slight yellowish mottle on the leaves can be observed with the naked eye, and this symptom is common in later susceptible plants or resistant varieties.
Heavy mosaic type: diseased leaves are yellow-green mottled, leaf-like protrusions, severe shrinkage, dark green, leaf margin curled backwards, leaf vein necrosis, plant susceptibility or early onset of dwarfing.
Shrinkage mosaic type: leaf veins prominence, leaf twisting, shrinking, dwarfing plants, less scarring.
Macular type: Shrinkage mosaic and light mosaic occur.
Buds withered: The top buds of the diseased plants are atrophic and curled, brittle and brittle, and are dark brown withered. The plants are dwarfed. Flower buds do not atrophy when flower buds are atrophied, or bean pods are deformed, resulting in irregular or round brown patches.
Brown granules: It is a manifestation of mosaic disease on seeds. Mottled seeds often produce mottled patterns, which are mottled or radial. The seeds of diseased plants are affected by climate or variety, and some are not mottled or rarely mottled.
(2) Prevention and control measures: selection of disease-resistant varieties; use of non-toxic seeds, establishment of disease-free fields, promotion of seeding in disease-free fields, strict selection of seeds before sowing, removal of brown spotted grains; thorough removal of diseased plants in soybeans During the growing period, the diseased plants should be completely removed; the seed field should be separated from the soybean production field and other crop fields by more than 100 m to prevent the spread of the virus; late sowing should be avoided, and the susceptible period of soybeans should be avoided during the peak period of the aphids; soybean and high-stalk crops should be used. Intercropping can reduce aphid damage and reduce disease.
2, soybean gray spot
(1) Symptoms: The main infestation of leaves can also invade seedlings, stems, pods and seeds. Seedlings growing from the seeds of the bacteria, the lesions on the cotyledons are semi-circular, slightly concave, and dark brown. In the rainy years, the growing point was infested and the seedlings died. The weather was dry and it only developed on the leaves. It was a faded green round spot at the beginning, and then it gradually expanded into a round shape with brown edges and a central gray or gray-brown frog-like spot. Sometimes lesions can also expand to ellipses. The central layer of grey mold (conidial stems and conidia) in the lesions on the dorsal surface of the leaves when wet. When the disease is severe, the lesions combine to make the leaves dry and fall off early. Stem lesions are oval or spindle-shaped, dark brown at first, and later become light gray. The lesions on the diaphragm are round or oval, slightly concave, and the color is similar to that of the leaf lesion. Because the surface of the bean paste is hairy, the mold layer is not easily visible to the naked eye. The lesions on the seeds were obvious, mostly frog eye-like taupe round spots with dark brown edges.
(2) Prevention and control measures: The selection of anti-(resistant) disease varieties has significant effects on the control of soybean gray spot disease; it should be rationally cropped to avoid heavy cropping; reasonably dense planting, strengthening field management, controlling weeds, and reducing field humidity; timely after harvest Clear the field sickness and plowing to reduce the amount of overwintering bacteria.
Chemical control measures spraying at the beginning of onset or during the period of scarring. The available agents are 50% carbendazim WP 1000 times spray; 75% chlorothalonil, or 70% thiophanate-methyl and other agents are also available. Spray once every 7 days and spray twice in succession.
3. Soybean aphids
Aphids can spread viral diseases. Adults and nymphs are concentrated on the parietal leaves, young leaves, and tender stems, causing yellow spots, and the number of leaf curling and scarring is reduced.
Available acetamiprid, pyrethroids, dichlorvos spray.
4. Soybean red spider
Yellow-white spots on the front of the leaves occurred; 3-5 days later the spots expanded and encrypted, and the leaves appeared red-brown spots; local curls, yellowed or red-brown scorch, deciduous or even light culms.
Available avermectin fenpropathrin, avermectin bufalin, tetrazine spray.
5. Soybean borer
The newly hatched larvae are pale yellow and turn milky white after entering the moltings; the leaves are backed up with leaf flesh or the leaves bite into nicks and holes.
Available chlorpyrifos, pyrethroid spray, or dichlorvos smoked adults.
6. Underground pests
The main pests of soybeans are earthworms, tigers, earthworms, and golden needles. Biting on the stem base or roots of seedlings caused dead seedlings, lack of seedlings, broken ridges, and reduced yields.
Available chlorpyrifos, pyrethroids (cyfluthrin, cypermethrin), insects music, soil plus water pouring.
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