Occurrence and control of soybean blight

Since July 2005, soybean blight spread to our state with the transportation of soybean seeds, our station immediately set up a soybean blight monitoring leading group, sending professional and technical personnel to carry out field monitoring work in Gongliu County.

I. investigation of morbidity

The occurrence area was 2239 hectares in 2005 and 2858 hectares in 2006.

1. Incidence of disease in Xinyuan County

Soybean planting area is 6700 hectares, investigation area is 3000 hectares, occurrence area is 2300 hectares, of which sporadic occurrence area is 2100 hectares. The distribution areas of soybean blight are mainly in Harabra Township, Shawerbrak Town, Talede Town, Xinyuan Town, Bestobie Township, and the main diseased varieties are Kesuo and Shi Soybean No.2.

two。 Incidence of disease in Gongliu County

The planting area of spring sowing soybean is 4300 hectares, and the replanting area is 5800 hectares. the main cultivated varieties of spring sowing are New Soybean No. 1, Stone Soybean No. 2, Xiangwen ~ 88, Wang Zhongwang, Hefeng 47 and Yi Soybean No. 1, which are mainly distributed in 10 townships, such as Agassen Township, Dongmaili Township, Tastobie Township, Teke Arek Township, towns, cattle Farm, Sheep Farm, Comprehensive Farm, Liangfan Farm and so on.

According to the preliminary investigation, the area of spring sowing soybean blight reached 325 hectares. Mainly occurred in cattle farms, sheep farms, Agarsen Township, Tastobie Township, Teke Arek Township and other townships (farms). Multiple cropping soybeans have not been found yet. The disease was serious in the varieties introduced in Northeast China, such as Xiangwen-88 and Hefeng 47, and the lighter varieties were Xinzhong 1, Wangzhongwang, Yidou 1 and Shizhong 2. Heinong 39 was not planted in 2006 because it was seriously ill in 2005.

3.71 regiment incidence

Soybean planting area of 667 hectares, disease area of 200 hectares, Heinong 39 is the main variety of the regiment, covering an area of 200 hectares, the original species transferred from Shihezi Academy of Agricultural Sciences, the incidence rate in 2006 was 1% 5%.

Second, symptoms

In our state, the prominent stage of soybean blight is mainly in the flowering stage, causing root rot, stem rot, plant dwarfing, wilting and death. The main root of the diseased seedling turned dark brown and the lateral root almost completely rotted. Waterlogged disease spots appeared on the diseased stem from the surface to the first branch, and then the stem festered and lodged. The leaves of susceptible varieties were yellowed, wilted and withered. In the adult stage, the main and lateral roots rotted, the dark brown ulcer spot appeared at the base of the stem, and the lesion site expanded upward, some appeared intermittently in the stem, and the disease node was as high as 4 ~ 8 nodes. The pith of the diseased stem blackened, the cortex and vascular bundle tissue necrosis, the base of the petiole near the disease spot blackened and sunken, the leaves drooped and withered, showing a figure of eight, but the leaves did not fall off. The leaves of the damaged plants yellowed from bottom to top, and then the whole plant withered and died. The plants infected later could bear fruit, but the base of the pod was waterlogged, the diseased part gradually expanded to the end, and the whole pod turned brown and dried up. When wet, the pod appears a black mildew layer. The seeds in the diseased pods were also infected, and the surface of the beans was light brown, brown to dark brown, dull, shrunken and withered, and the beans became smaller.

III. Conditions for onset of disease

The key factor affecting the occurrence of the disease is soil temperature. Soybean blight is spread by bacteria. Soil or disease residue is the main source of disease, which is spread through precipitation and irrigation water. Therefore, sufficient water is a necessary condition for disease infection and epidemic.

IV. Affected plots

The disease mainly occurs in night tide land, stagnant water land and low-lying land with high groundwater level. In the land with high groundwater level, the plants with serious disease are in the stagnant water and outlet.

V. Prevention and control measures

1. For the land where the epidemic occurs, organize labor, pull out the diseased plants and destroy them.

two。 Crop rotation, soybean blight occurred in the land is strictly forbidden to replant soybeans, requiring seed production units to strictly prohibit the transfer of seeds from other provinces.

3. Temporarily define the epidemic area, prohibit soybean seeds from the epidemic area to the non-epidemic area.

4. Seed fields with soybean blight shall not be allowed to plant seeds or issue quarantine certificates of origin.

5. At the initial stage of the disease, 58% methyl frost phosphorus manganese zinc wettable powder 100 g / 667 square meters was used to spray the water, and the plant in the disease center was affected by chemicals and soil temperature, and the disease was alleviated.