Introduction to the symptoms, causes and control measures of soybean virus disease

In the process of soybean growth, some virus diseases will occur, which will seriously affect its growth. Soybean virus disease is a systematic disease, which is widely distributed and generally occurs in various soybean producing areas. Let's take a look at the symptoms, causes and control measures of soybean virus disease.

Symptoms of soybean virus disease

1. Light mosaic type

The leaves are flat, the naked eye is yellow mottled, the diseased leaves are mottled yellow and green through the sunlight, and the plant growth is basically normal. Most of the resistant varieties and later infected plants showed this symptom.

2. Wrinkled leaf and mosaic type

The leaf is shrunken and crooked, the leaf vein is bubbly, the plant is dwarf, and the pod is few.

3. Heavy mosaic type

The diseased leaves are yellow and green alternating with mosaic, severely wrinkled, mesophyll protruding, leaf margin curled backward, vein necrosis, dwarf plant, dark green.

4. Macular type

It is generally mixed with light mosaic and wrinkled mosaic symptoms. There are two types of this condition, one is macular necrosis, which is common in the south, and the other is the northeast macular mosaic. The two phenotypes are more common in the podding stage. The leaves of the former plant are yellow and mottled, the veins of the leaves become brown and necrotic, and the old leaves are generally not wrinkled, but the upper leaves of the plant are mostly wrinkled.

5. Bud withered type

The apical buds of the stem tip and lateral branches of the diseased plant were reddish brown or brown, atrophied and curled, and finally withered in black brown, the plant was dwarfed and the stem was easy to break. Most of the flower buds wilted and did not bear pods during flowering. During the podding period, the symptoms were round or irregular brown patches on the pods, and most of the pods became deformed.

6. Brown spot type

It varies depending on the color of the navel of the bean. The seeds of the brown navel are mottled brown, the yellow-white navel is light brown, and the black navel is black.

Second, the cause of soybean virus disease

In the high temperature and dry weather environment, the use of immature farm manure, the land with late planting, the plot with small seedling age, the plot with insufficient water and fertilizer during the expansion period of fruit trees, the plot with excessive amount of nitrogen fertilizer, the plot with barren soil, the compacted plot and the plot with high soil viscosity, the physiological resistance of soybean plant is poor, the incidence of virus disease is more serious, and the yield is reduced greatly.

III. Prevention and control measures of soybean virus disease

1. Agricultural measures

Strict seed selection before sowing to remove brown spots. Sowing at the right time to make soybeans blossom before the planthopper blossoms. Pull out diseased seedlings at seedling stage, control white planthopper in time, strengthen field management, cultivate strong seedlings and improve disease resistance of varieties.

2. Breeding and popularizing virus-resistant varieties

Because soybean mosaic virus is mainly transmitted by seeds and there are great differences in disease resistance among varieties, and because the physiological races of soybean mosaic virus are different in different places, the disease resistance of the same variety planted in different areas is also different, therefore, disease-resistant varieties should be selected and promoted on the basis of identifying the main physiological races of mosaic virus in this area.

3. Establish a disease-free seed field.

Many of the viruses infecting soybean are transmitted through seeds, so planting virus-free seeds is one of the most effective ways of control. Two points should be paid attention to in the establishment of an avirulent seed field: one is that there is no virus host plant within 100 meters around the seed field, and the other is that the diseased plant should be removed in time after emergence, and the diseased plant should be pulled out again before flowering, and the non-toxic seed can be obtained after 3-4 years of planting. The seed transmission rate of primary seeds is less than 0.1%, and that of commercial seeds (field seeds) is less than 1%.