Growing vegetables is most afraid of encountering stem rot, how to solve stem rot?

Whether it is a greenhouse or an open field to grow vegetables, what is indispensable is to see all kinds of vegetable diseases. The most often is after the seedlings are transplanted, and we often see some stem rot.

Stem rot symptomatic characteristics

It mainly harms stems, but can also harm corollas and seeds. When the stem near the ground is susceptible, it produces long brown patches and shrinks. Because stem disease often causes root rot, leaves also wither due to stem rot, which eventually leads to plant death.

When the corolla and seeds are infected, they also turn brown and rot.

Incidence of stem rot

The causative agent of marigold stem rot is Phytophthora fungi. Low-lying areas with continuous rain or poor drainage are prone to disease, and the disease is severe. The severity of the disease is directly related to the disease resistance of the variety.

In general, small marigolds (peacock grass) and dwarf varieties are more resistant to disease, while African species are the most susceptible.

After such a rhizome has developed a disease, we should be able to irrigate the roots. The same two people went to irrigate the roots, but the results were different. Some people think that the effect of root irrigation is better, but some people think that the effect of root irrigation is not so good.

So how to irrigate the roots to treat the effect well?

1. Selection of fungicides

When we use fungicides, we have to be selective. For example, if we use some methacozebin for the first time, then we need to change the formula for the second time, for example, we should use mancozeb or enoylmorpholine to use it alternately.

2. Watering

When we do root irrigation, it is best not to water three to four days before the root irrigation or not to water three to four days after the root irrigation. Watering before and after root irrigation will lead to a decrease in the concentration of the dilution of the solution, which will not achieve a good effect.

In addition, it is best to use some microbial agents when irrigating roots. Microbial agents have a good effect on root irrigation, that is, to overcome bacteria.

3. Treatment measures for excessive root irrigation

If the concentration is too large when irrigating the roots, it will not only fail to have a good effect, but can lead to root rot; It can even cause yellowing of the leaves. If this is the case, gibberellin can be sprayed with sugar. When spraying, it should be sprayed little by little, and the amount must be small.

This can alleviate the phenomenon of high root concentration.

Cut the lesion with a clean blade, removing any area that has been infested by stem rot until the fresh flesh is exposed. Of course, if the root system is infected, it must be cut off together, and all the diseased bodies should be cut off as well.

How to prevent and control root rot of vegetable seedlings?

Use resistant and disease-resistant varieties. In Northeast China, the more disease-tolerant varieties include Tianyan No. 6, No. 3, No. 4 and Fanyu No. 1 and No. 2. Mix seeds with 90 dixone powder or 35 phenanthraquinone powder by seed weight.

Strengthen seedbed management. Do not flood irrigation, pay attention to loosening soil moisture, and increase soil permeability. At the same time, we should do a good job in underground pest control and reduce root wounds.

Root rot is often similar to the symptoms of root rot and is a fungal disease. The pathogen overwinters in the soil and on the diseased residues, generally occurs in late March to early April, enters the peak period of disease in May, its occurrence has a great relationship with climatic conditions, low temperature and high humidity of the seedbed and insufficient light are the main environmental conditions that cause the disease, and the soil in the seedling field is sticky, easy to harden, and poor ventilation causes the root growth and development to be hindered and also prone to disease.

Choose disease-resistant and disease-resistant varieties according to local conditions. Crop rotation with non-gramineous crops to avoid or reduce continuous cropping. Choose disease-free seeds, sow early and shallowly at the appropriate time, and avoid sowing under the condition that the soil is too wet and too dry.

Increase the application of organic fertilizer, phosphorus and potassium fertilizer, and apply an appropriate amount of fast-acting nitrogen fertilizer when returning to green. Reasonable drainage and irrigation to prevent wheat from long-term drought and waterlogging, and pay attention to frost prevention during the wintering period. Diligent cultivation to remove grass weeds in the field.

After the wheat is harvested, plough and eliminate stubble in time to promote the decay of diseased residues. After the straw is returned to the field, it should be ploughed and buried in the ground.

Root rot is a disease caused by fungi, which causes root rot, gradually weakens the ability to absorb water and nutrients, and finally dies of the whole plant, which is mainly manifested as yellowing and wilting of the whole leaf.

The disease is often similar to the symptoms of the root and is a fungal disease. The pathogen overwinters in the soil and on the diseased residues, generally from late March to early April, and enters the peak period of disease in May, and its occurrence has a great relationship with climatic conditions. Low temperature, high humidity and insufficient light in the seedbed are the main environmental conditions that cause this disease.

The soil in the nursery area is sticky, easy to harden, and poor aeration, which leads to the hindrance of root growth and development, and is also prone to disease. In addition, after the roots are harmed by underground pests and nematodes, there are many wounds, which is conducive to the invasion of germs. In this environment, not only herbaceous flowers that are sown and cut are susceptible, but also woody flowers such as Yueji, Hibiscus, and Hibiscus are also susceptible to diseases when propagated by cuttings, branching, and stripping.

There are many ways to prevent and control root rot of vegetable seedlings, which can be controlled by soil disinfection and pesticide control, and root rot can also be prevented and controlled by simple agricultural pouring tea, applying fully rotted farmhouse fertilizer, reasonable irrigation and other methods.

Choose disease-free and strong seedlings. When transplanting and planting vegetable seedlings, we must choose strong seedlings without disease, which is one of the most important measures to reduce the occurrence of root rot after transplanting and planting vegetable seedlings in solar greenhouses.

Strengthen seedbed management. Do not flood irrigation, pay attention to loosening soil moisture, and increase soil permeability. At the same time, we should do a good job in underground pest control and reduce root wounds.

Seedbed disinfection and pesticide application control. In the early stage of the disease, spray with 10 double-effect Lingshui 200 300 times or 50 carbendazim wettable powder 400 times or 50 Dixone 800 times.

First, the law of occurrence.

1.The pathogen of pepper root rot is Fusarium rot, which can survive in the soil for more than 10 years, and the transmission channels are mainly spread by fertilizers, tools, rainwater and running water.

2.The occurrence of pepper root rot is closely related to temperature, and 22 26 is the most suitable for the disease.

3.The greater the humidity of pepper root rot, the more serious the disease, the more serious the disease is when flooded with water, and the disease is light when watered with small water.

2. Symptoms Pepper root rot mostly occurs after planting. At the beginning of the disease, the branches and leaves, especially the top leaves, wilted slightly, and recovered from the evening to the next morning, and all the leaves wilted after several days of repeated symptoms, but the leaves were still green. The rhizome and root cortex of the diseased plant are light brown and dark brown rot, which is easily peeled off and exposes the xylem. Transverse cutting of the stem shows that the vascular bundles turn brown, and in the later period, when wet, white to pink mold can be seen.

3. Prevention and control 1Crop rotation. It is rotated with Chinese cabbage, cabbage, garlic, green onions and other crops for more than 5 years.

2.Eliminate the source of primary infection. In general, pepper seedlings should be raised by themselves, if you need to buy seedlings, never buy them in the diseased area, so as to effectively prevent the spread of pepper root rot caused by the purchase of seedlings.

3.Scientific management to prevent water accumulation. When preparing the land, dig a drainage ditch at one end; Ridge planting is used to make a high ridge with a width of 90 cm, and one ridge is planted in two rows, which is not only conducive to early ridge sealing, but also conducive to ventilation and lighting and field management; Use fully decomposed organic fertilizer, top dressing in the middle and late stages, and use the prepared compound fertilizer mother liquor to be watered with watering, or watered after spreading along the ridge to prevent injury to the roots of pepper caused by human management.

4.Treatment of diseased plants. If one or several plants are found in the pepper field and wilt at noon and recover slightly at night, they should be pulled out immediately, taken out of the field and burned, and then buried with soil mixed with lime.

1.Crop rotation. It is rotated with Chinese cabbage, cabbage, garlic, green onions and other crops for more than 5 years.

2.Eliminate the source of primary infection. In general, pepper seedlings should be raised by themselves, if you need to buy seedlings, never buy them in the diseased area, so as to effectively prevent the spread of pepper root rot caused by the purchase of seedlings.

3.Scientific management to prevent water accumulation. When preparing the land, dig a drainage ditch at one end; Ridge planting is used to make a high ridge with a width of 90 cm, and one ridge is planted in two rows, which is not only conducive to early ridge sealing, but also conducive to ventilation and lighting and field management; Use fully decomposed organic fertilizer, top dressing in the middle and late stages, and use the prepared compound fertilizer mother liquor to be watered with watering, or watered after spreading along the ridge to prevent injury to the roots of pepper caused by human management.

4.Treatment of diseased plants. If one or several plants are found in the pepper field and wilt at noon and recover slightly at night, they should be pulled out immediately, taken out of the field and burned, and then buried with soil mixed with lime.

Symptom recognition. The causative agent of pepper stem base rot is S. solizum, which is a fungal disease. The symptoms vary according to the different growth stages of peppers.

After sowing, the disease can cause rotten seeds and rotten buds, which will die without soiling, and there will be lack of seedlings and broken ridges on the ground. After the emergence of the disease, the base of the rhizome produces oval brown necrotic spots, and after the diseased part expands, the base of the stem presents black necrosis, shrinkage and narrowing, and the diseased part is erect and dies. When the humidity is high, the disease grows white hyphae visible to the naked eye.

At the beginning of the adult plant stage, the external lesions of the cortex at the base of the stem were not obvious, but the leaves above the base of the stem showed whole plant wilting, and the leaf color became lighter. As the lesion expands, the cortex at the base of the stem gradually turns brown and finally blacken. When the lesion expands around the base of the stem, the lesion loses water and shrinks.

Because the stems of the adult plant stage have been lignified, the degree of shrinkage of the diseased part is not as obvious as that at the seedling stage. At the base of the longitudinal section of the diseased stem, the xylem can be seen to be browned, but the vascular bundles do not change color. The roots and root system were also normal, and there was no white mucus overflow in the cross-section of the stem.

These are the main differences from wilt, root rot and bacterial wilt. In the later stage of pepper stem base rot, all the leaves on the ground part of the plant turn yellow and die, and most of them remain on the diseased plants and do not fall off.

2. Transmission route and pathogenesis conditions.

The pathogen of the disease overwinters in the soil or with the diseased residues, and directly invades the host stomata or epidermal cells with hyphae. After the plant is susceptible, the mycelium produced by the diseased part is re-infected and spread through irrigation water or agricultural operation bands. Generally, the ground temperature is 16 20, the soil is dry and wet or the seedlings are growing, and the disease is easy under the condition of high temperature and high humidity.

3. Prevention and control methods.

1. Since the disease is a soil-borne disease, the greenhouse floor should be cleaned before transplanting and planting peppers, and high-temperature stuffy sheds should be carried out to reduce the pathogen base in the soil.

2. When transplanting and planting, choose disease-free strong seedlings. Increase the application of phosphorus and potassium fertilizers to improve the disease resistance of plants.

3. Pharmaceutical prevention and control. In the early stage of the disease, 1000 times of 1% shenzimycin suspension, or 1600 times of 70% oxazinyl wettable powder, or 2000 times of 30% difenomecline file and propiconazole emulsifiable concentrate can be used to irrigate the root or spray the base of the stem. Generally, depending on the condition, it can be taken once every 7 10 days, and 2 or 3 times in a row.

Choose disease-resistant varieties and soak them before sowing. First, pre-soak the seeds with cool water for 1-2 hours, then soak the seeds with 1% potassium permanganate solution for 20 minutes, and then rinse with warm water until neutral and then soak the seeds; Or soak the seeds with 96% Oxazalin 3000 times solution for 30 minutes, wash with water and soak the seeds for 6 hours. After wrapping it in a damp cloth, it was seeded under 30 conditions.

Combined with other comprehensive control measures such as spraying "Tianda-2116" to improve its disease resistance, indoor crops are not susceptible to disease.

2) In the early stage of the disease, use 96% Oxazalin 3000 times + 2116 600 times a day for prevention and control, spraying or irrigating roots 2-3 times every 10 days. At the same time, combined with foliar spraying of Tianda 2116 600 times, it can promote the recovery of the root system as soon as possible.

3) Strengthen cultivation management. After the green pepper is planted, it can prevent flood irrigation, cultivate and loosen the soil in time, enhance soil permeability, and promote root wound healing and root development. And timely ventilation and humidity removal to avoid high temperature and high humidity.

Apply organic fertilizer to rot, use an appropriate amount of chemical fertilizer, and avoid burning roots. Remove the diseased plants in time and take them out of the greenhouse to prevent the spread of the disease.

That's right, if this happens, try to get rid of the bad one, so it will be contagious.

Prevention and control methods of stem rot (1) Clean the garden in autumn, cut the diseased branches and burn them intensively to eliminate the pathogen; (2) Half of the onset time is from May to August, and (2) It can be sprayed from May to August. In mid-May and early July, 500 times of methyl tobuzine solution or 500 times of 40% ethyl phosphorus aluminum or 500 times of Fumeishuang solution were sprayed on the susceptible varieties. (3) Requirements for drug spraying and drug spraying:

Drugs should be atomized sprayed to solve the problem of pesticide residues, and fog machine spraying is usually used in the world. Control methods (1) The increase of the disease in recent years is closely related to the poor disease resistance of some breeding materials and the change of cultivation conditions. Therefore, the selection of disease-resistant inbred lines and the cultivation of disease-resistant hybrids are the primary control measures.

2) The pathogens that cause stem rot are weak parasitic bacteria, which can infect plants with weak growth potential. Measures such as strengthening cultivation management, reasonable fertilization, reasonable dense planting, and reducing soil moisture can make plants robust and reduce stem rot. (3) Reasonable crop rotation, deep ploughing of the land, removal of disease residues and non-application of unrotted organic fertilizer can reduce the source of bacteria in the field and achieve a certain control effect.

4) Preventive medication: 30ml of R. solanacearum Rick mixed with 15 kg of water, irrigated roots, irrigated once in 7-10 days, and irrigated 2-3 times in a row. (5)**Medication:

1. In the middle and early stage of the disease: 50ml of R. solanacearum Rick mixed with 15 kg of water, irrigated the roots, irrigated once in 7 days, and irrigated 2-3 times. If the pathogen is harmful to the aboveground part at the same time, the root should be poured at the same time, the aerial part should be sprayed at the same time, once every 7 days, when spraying, 50ml + 40ml of R. solanacearum can be added per 15 kg of water to add 50ml + 40ml of Jinbei or Wofengsu.

2. In the middle and late stages of the disease: when the disease is severe, in order to achieve a faster effect, some chemical agents can be added when irrigating the roots or spraying, such as: 50ml of R. solanacearum + 15 grams of methaloxalic, or 25g of methamalene manganese zinc or 20g of 20% leaf dryazole.