What are the symptoms and causes of soybean root rot? What are the prevention and control measures?

The pH is not suitable, there is no frequent watering, too much fertilization, the temperature is too high, and pesticides are not sprayed regularly, so this situation occurs; Regular watering must be fertilized, watering must be even, must often pencil pesticides, must do a good job of field management.

Soybean plantation is a common disease, and the impact on soybean is very large, the main is that the root lesions will be brown or black-brown spots at first, and then it will be rust-colored or reddish-brown and black-brown when it is particularly serious, mainly because the soil temperature is too low, the growth is weak, and the opportunity for pathogens to invade will increase; Agricultural prevention and control, chemical control, if the appropriate amount of phosphorus and potassium contains micro fertilizer, improve the ability of soybean roots to resist disease.

It may be that pests and diseases have occurred, or it may be that there is too much watering, which causes the roots to rot; It is necessary to spray pesticides in time, stop watering, keep the air dry, the soil is moist, and do not water too much.

I think the disease is that the soybean plant loses green, yellow, the plant is short, wilted, and seriously will cause dead trees, and the occurrence of ** is too deep sowing, too early sowing, soil problems, fertilization methods; The first is to enhance organic matter, supplement trace elements, soybean seed coating, seed dressing, fungicide**.

First, let's take a look at the symptoms of root rot: the affected seeds are soft, unable to germinate, and have a white mold layer on the surface. After emergence, it damages the roots and stem base of diseased plants, forming brown oval or elongated lesions, and even harming lateral roots.

In the later stage, the roots turn dark brown and the epidermis rots. The diseased plant is dwarf yellow, and the lower leaves fall off early. Strengthen field management, level fine rake, improve soil aeration, timely deep ploughing and soil weeding, timely removal of stagnant water after rain, and prevent too much humidity.

Adjust sowing date and sowing depth: Determine the sowing date according to the rising soil temperature, and avoid early sowing in cold areas. Under the premise of preserving moisture, the sowing depth should not exceed 5 cm as much as possible.

<> soybean root rot, the pathogen is a very saprophytic pathogen, which can overwinter normally in the soil or in crop disease residues, and becomes the first pathogenic bacterium in the field in the following year. The greater the soil moisture, the more water and the lower the temperature, the more conducive to the development and reproduction of root rot pathogens. The soil is moist and sticky, the permeability is poor, the germs multiply quickly, and the number is large, which aggravates the damage of soybean.

Sowing too deep and too early, the seedlings emerge slowly, and the young rhizomes are slender, which increases the probability of invasive diseases and damages. The sowing depth should not exceed 5 cm.

In the early stage of soybean infection, the aboveground part is not easy to see, and it is the same as normal plants, which often delays the best time for control. In the underground part, the manifestations of the root system can be seen, and the disease is a water-soaked brown spot, round or irregularly shaped and concave, and gradually develops to the lower part of the root system, necrosis and decay. As a result, soybean roots, fibrous roots are reduced, and seedlings die before they are unearthed; The adult plants are short and poorly grown, with few and small pods, which seriously reduces the yield and affects the oil yield and oil quality of soybeans.

Soybean root rot, a fungal, disease, is one of the more common diseases in the soybean growth period, the harm to soybeans is large, widely distributed, in the north and south of China soybean planting areas have occurred, according to the specific situation, the severity of the disease is different.

It mainly includes: (1) Strengthening quarantine: quarantine should be strengthened to prevent the expansion of epidemic areas, especially the quarantine of seeds transferred from epidemic areas.

2) Promotion of disease-resistant varieties: the resistance of different varieties to soybean root rot varies greatly. Therefore, disease-resistant varieties are widely used in disaster-stricken areas to reduce or avoid the occurrence of diseases.

3) Strengthen field management, remove stagnant water in the field in time, loosen the soil by cultivating the soil, apply more organic fertilizer, and increase soil permeability, which is conducive to reducing diseases. (4) Implement crop rotation: crop rotation can reduce the number of pathogens in the soil and reduce the occurrence of diseases.

Chemicals Treating seeds with RadoX can effectively inhibit cataplexy at seedling stage.

Chemical agents have played a certain role in the prevention and control of root rot fungi, through the treatment of soybean seeds, adding a small proportion of chemical components to the seeds, you can get a good effect of soybean plants resistant to root rot, and chemical agents can also be added to the soil to prevent the production of root rot fungi, but we must pay attention to the amount of chemical agents, adding too much may change the characteristics of the soil, and more serious may pollute the soil and pollute the environment.

(1) Strengthen quarantine: Due to the local occurrence of Phytophthora soybean root rot, quarantine should be strengthened to prevent the expansion of epidemic areas, especially to strengthen the quarantine of seeds transferred from epidemic areas.

2) Promote disease-resistant varieties: the resistance of different varieties to soybean root rot is very different, therefore, disease-resistant or disease-resistant varieties are widely used in the affected areas to reduce or avoid the occurrence of diseases.

3) Strengthen field management, remove stagnant water in the field in time, loosen the soil in cultivation, apply more organic fertilizer, and increase soil permeability, which is conducive to reducing the incidence of disease.

4) Implement crop rotation: Crop rotation can reduce the number of pathogens in the soil and reduce the incidence of disease. Chemical agents Treating seeds with Redomyces can effectively inhibit cataplexy at seedling stage.

Redomycete is a systemic fungicide, mainly concentrated in the aboveground part, the ability to protect the root system is weak, and it can also be used for soil treatment, especially when combined with disease-resistant varieties. It can also be used 70% Baidefu manganese zinc, 64% alum and 72% Kelu wettable powder for seed treatment before sowing, and the dosage is the amount of seeds38%。

Soybeans are an annual herb of the genus Soybeanaceae, native to China, and now widely cultivated around the world. Soybeans are one of the important food crops in China, and there are already 5,000 of them. years of cultivation history.

Northeast China is the main soybean production area, and soybean itself is rich in vegetable protein, so it is often used to make soy products, extract soybean oil, brew soy sauce and extract protein.

Soybeans are known as the king of beans, the road to the field, and the green milk, and are arguably the most respected foods among hundreds of natural foods. Soybeans themselves prefer warm zones, and the seeds begin to germinate at around 12 degrees. The suitable temperature for growth is 20 degrees Celsius to 25 degrees Celsius, and the suitable temperature for flowering and poding is 20 degrees Celsius to 28 degrees Celsius.

If there is a drop in temperature, the scab will be delayed, and if the temperature is below 14, the plant will not flower, and if the temperature is too high, the plant will end its growth early.

Soybeans actually absorb less than 15% of the total amount of fertilizer before flowering, but once they bloom and set poddings, the amount of fertilizer absorbed will account for more than 80% of the total amount of fertilizer. There are many places to pay attention to when planting soybeans, especially soybean root rot, which is easy to occur at the seedling stage, which is mainly manifested as the formation of reddish-brown in the taproot of seedling disease and the base of the stem close to the ground, with slightly concave lesions, and the cortex cracks into ulcers. In severe cases, the lower half of the taproot will rot completely, and it will even wither and die.

Soybean root rot** is mainly transmitted by viruses, so you want to prevent soybean root rot. First of all, it is necessary to take turns sowing with non-host crops such as millet, corn, peanuts, etc., and increase the amount of potassium fertilizer, phosphate fertilizer, farmhouse fertilizer, etc. And timely watering, weeding, and cultivating in times of drought can improve the disease resistance of soybeans and reduce losses.

Secondly, before sowing soybeans, 50% of the weight of the seeds should be used for double dressing. Finally, spray pesticides before the onset of soybean disease or at the beginning of the disease, and it is recommended to use 600 700 times of 75% chlorothalonil wettable powder, spray once a week, and spray 1 2 times continuously.

The above is the prevention and control method of soybean root rot, if there is still no way**, you can ask local experienced farmers, or consult agricultural experts.

Choose late sowing at the right time, start sowing when the ground temperature is stable through 8 9, and require its depth not to exceed 5 cm; Sufficient basal fertilizer, seed fertilizer and timely top dressing should be applied, and new high-fat film combined with multi-compound liquid fertilizer should be used for foliar fertilization, which can make up for the lack of fertilizer and water absorption by root diseases. It is necessary to implement cultivated soil cultivation in time to promote the formation and recovery of new lateral roots at the base of aboveground stems.

For pesticide control, soybean seed coating containing formabi, carbendazim and insecticides is used for seed dressing, and the dosage is the weight of the seed, which can effectively prevent root rot; For every 100kg of seeds, add 20% Apulon 40ml with 150ml EC of Clerus. It should be noted that because the effect of pesticide seed dressing generally only lasts for 2 to 3 weeks, it is necessary to adopt the method of cultivating soil, which will be conducive to the formation of new roots on the side, so as to replenish fertilizer and water in time. In addition, biologics seed dressing is also available

Soybean root fungibilizer was selected, and the seeds required per hectare were dressed with 1500ml liquid agent; Fungus poison gram, with 2% of the weight of the seed fungus poison gram water agent dressing.

Choose disease-resistant varieties, rotate with non-host crops such as corn, millet, peanuts, etc., and increase potassium fertilizer, phosphate fertilizer, and farmhouse fertilizer when sowing. Strengthen field management, timely deep ploughing, cultivating soil and drainage.

<> soybean root rot can be controlled by watering 1000-2000 times of 70% dioxalin wettable powder, 800-1000 times of 50% carbendazim wettable powder, or 500-600 times of 20% Runkella suspension agent. When planting soybeans, it is necessary to choose disease-resistant seeds and adopt a cultivation mode of mulching film to avoid the bacteria in the soil from harming the aboveground plants.

1. What medicine is used for soybean root rot?

1. Pharmaceutical prevention and control.

Generally, 1000-2000 times of 70% oxazine wettable powder, 800-1000 times of 50% carbendazim wettable powder, 500-600 times of 20% Runkea suspension agent, 300 times of 10% double-effect Lingshui agent and other agents can be used to prevent and control soybean root rot, usually by watering.

2. Agricultural prevention and control.

1) It is necessary to apply fully decomposed organic fertilizer, and the organic fertilizer can not be mixed with the residue and decay of the previous crop.

2) Select seeds with strong disease resistance, and coat the seeds, if they are not coated, they should be sterilized with seed dressing agent or soaking agent.

3) Pull out the diseased branches, leaves, and plants in the field in time and take them out of the field for burning.

4) The cultivation mode of mulching is usually effective in preventing and controlling the germs in the soil to damage the aboveground plants.

2. What causes soybean root rot?

1. The cause of the disease.

1) Sowing too deep: soybeans are generally not suitable for deep sowing, and in the environment of deep sowing and moist soil, root rot is prone to occur.

2) Sowing time too early: If the soybean is sown too early, it is easy to have a certain impact on its growth, and if it encounters a wet low-lying plot at this time, it is easy to be infected with root rot.

3) Soil pathogens: Because soybean root rot is a soil-borne disease, if the pathogens in the soil are not eliminated in time, then root rot will always be prone to occur.

2. Symptoms of onset.

1) When soybean root rot occurs, its root growth is not robust, the number of capillary roots is small, the number of nodules is small, or even there is no nodules, and the color of the root tips will turn brown, similar to water immersion.

2) After the root system is damaged, it will affect the ability of the root system to transport nutrients and water to the plant, which will lead to symptoms such as green loss, yellowing, dwarf and wilting of soybean plants, and even death in severe cases.

1. Sowing too deeply; Soybeans are crops that should not be planted deeply. Deep sowing and moist soil make this growing environment susceptible to root rot.

2. Sowing too early: Sowing soybeans should not be sowing too early. The temperature suitable for soybean germination and seedling growth is 20-25. Early sowing does not meet the temperature requirements. In addition, if you encounter a low land with a lot of moisture, you are also susceptible to root rot.

3. Soil problem: soybean root rot is a soil infectious disease. If it does not happen immediately, it will happen every year in the future, especially after the root system is bitten by underground pests, and the invasion of pathogens will be accelerated.

Soybean root rot mainly occurs in the seedling stage, the lesions at the base of the seedling stem are brown dots at the beginning, and after expansion, they are diamond-shaped, elongated or irregularly shaped, and the lesions are reddish-brown or black-brown when the disease is severe, and the cortex rots and is ulcer-like. The root lesions are also punctate at the initial stage, and after enlargement, they are reddish-brown or black-brown, elongated or irregularly shaped, and the taproot and fibrous roots of the severely diseased plants rot, resulting in bald roots.

The aboveground part of the diseased plant has poor growth, the diseased seedlings are short and thin, the leaves are small and pale in color, and they dry up and die in severe cases. At the adult stage, the roots of the diseased plants produce brown spots, irregular shapes, different sizes, no fibrous roots in the diseased parts, and the aboveground parts are thinner and smaller than the healthy plants, and there are fewer pods.

Soybean root rot is a typical soil-borne disease, and the pathogen can attach to the seed and cause the disease before the seedlings emerge. Therefore, the disease of soybean continuous cropping plots is serious, and the longer the continuous cropping period, the more serious the disease. Low-lying land or continuous rainfall is prone to disease, and the disease is also serious if the disease is sown too early and too deep, the seedlings are slowly unearthed and the disease is also severe in heavy cropping plots.