What are the symptoms of sclerotinia sclerotinia and what drugs are used to prevent and treat it?

It can occur throughout the growth period, resulting in rot of stems, stem bases, flower discs and seed kernels.

There are four common symptoms: root rot, stem rot, leaf rot and flower rot, among which root rot and flower rot are seriously affected.

The rot type can occur from the seedling stage to the harvest stage, and the young shoots and radicles are soaked in brown spots when the seedlings are infected, and they rot after expansion, and the seedlings can not be unearthed or can be unearthed, but wilt and die with the expansion of the lesions. At the adult stage, the infected root or stem base produces brown lesions, gradually expands to other parts of the root and stems, and then expands upwards or left and right, up to 1m long, with concentric ring patterns, when wet, the disease grows white hyphae and rat fecal-like sclerotia, and the seriously diseased plants wilt and die, the tissue decays and is easy to break, and there is black sclerotia inside.

The stem rot type mainly occurs in the middle and upper part of the stem, with oval brown spots at the beginning, which expand later, the lesions are light brown with concentric wheel patterns, the leaves above the lesions are wilted, and the surface of the lesions rarely forms sclerotia.

Leaf rot lesions are brown oval, slightly concentric whorls, and quickly spread to the whole leaf when the humidity is high, and the lesions are split and perforated or shed from the middle when the weather is dry.

At the beginning of the flower rot type, brown water-stained round spots are born on the back of the flower disc, and after expansion, the whole flower disc can be reached, the tissue becomes soft and rotten, and white hyphae grow out when the humidity is high, and the hyphae spread between the seeds and fruits through the flower disc, and finally form a reticulated black sclerotia, black sclerotia of different sizes can be seen inside and outside the flower disc, and the fruit can not ripen.

It can be controlled with agents such as ethylene sclerotium, Sukrin, and sclerotinia sclerotiorum.

Sunflower can be damaged at all growth stages, and pathogens can infect roots, stems, leaves, flower discs and other parts, forming root rot, stem rot, rotten discs, etc.

1) Root rot type. The main part of the disease is the base and root of the stem, which is immersed in water at first, and white hyphae grow out when wet, and the base of the stem shrinks after drying, and the whole plant dies in a withered state, and the hyphae condense into a clump to form a rat feces-like sclerotia around the base.

2) Stem rot type. It occurs in the adult stage, mainly infects the base and middle and lower part of the stem of the plant, the lesions are brown and water-soaked at the beginning, the stalk is easy to be broken, and a large number of sclerotia are formed inside and outside the stem.

3) Disc rot type. It mainly occurs at the end of sunflower flowering, when all or part of the back of the flower disc appears water-soaked lesions, turns brown and softens, and the whole flower disc decays, grows white hyphae, gradually produces sclerotia, and falls off on its own.

The prevention and control of sclerotinia sclerotinia in sunflower is mainly based on agricultural control and disease-resistant varieties. The prevention and control methods are as follows:

1) Sunflower seed production and breeding base should be subject to strict quarantine of origin.

2) Reasonable crop rotation, at least 3 years or more of the rotation period.

3) Choose disease-resistant varieties.

4) Strengthen cultivation management. Adjust the sowing date, early or late sowing at the right time; The sunflower field should be subsoiled and deeply cultivated, with a depth of 10 15 cm, and the sick and disabled bodies should be cleaned up in time to reduce the source of the disease; reasonable sparse planting, advocating wheat and sunflower intercropping; Reasonable fertilization and cultivation of strong seedlings.

5) Pharmaceutical prevention and control. Soil treatment: mix an appropriate amount of sandy soil with 1 kg of 50% Pythium remittable powder per mu, and apply it evenly with the seed in combination with sowing.

Seed treatment: fludioxonil suspension seed coating agent, 40% sclerotia net wettable powder according to the amount of seeds. Spraying:

50% Pythium 1500 2000 times liquid, more than 40%? Sclerotinia (carbendazim + sclerotia) wettable powder 1000 1500 times, 50% carbendazim wettable powder 500 times, 40% sclerotia net wettable powder 800 times liquid evenly sprayed.

The incidence of sclerotinia sclerotinia in sunflower is extremely high, as high as 80% in severe cases, it is impossible to prevent it, it can occur in each period, and it has a great impact on the plant.

Types of sclerotinia sclerotinia in sunflowers.

Sclerotinia sclerotinia is mainly a fungal infection that causes the flower disc of the plant to rot and the whole plant to wilt. There are two common types:

Withered type. It occurs mainly in the seedling stage. Water-stained lesions appear on the stems, and white flocculent hyphae gradually grow, which will turn black when the air is dry, and the plant will gradually die. At the time of onset, the stems are mainly dominant, and the leaves are yellowish from the bottom to the top.

Rotten type. This disease mainly appears after the flowering, the flower disc appears lesions, and the receptacle is soft and brown. In case of rain, the lesion gradually expands, the disease worsens, and the entire flower disc is covered with hyphae, causing decay.

Prevention and control measures: physical control.

Once a lesion is found on the stems, leaves or flower disc of the plant, the whole plant is uprooted to prevent the fungus from spreading. The sclerotia is very vigorous and will survive in the soil for 3 years, so if there are other plants in the pot that leak the code, it is recommended to change the soil and replant.

Pharmaceutical prevention and control. 1. Spray 1000 times of Tobuzin's solution before the bud and spray 1 2 times.

2. Budding and flowering stage: spray 1000 times of the withering solution, mainly spraying on the lower part of the plant and the back of the flower plate.

3. Spray Sukelin 500 solution at the seedling stage or flowering stage, spray once every 5 10 days, and the prevention effect is first-class.

4. When the temperature reaches 18 20, it is the best time for surface spraying. At this time, 70% pentachloronitrobenzene mixed with a small amount of wet soil is sprinkled on the soil surface, which can effectively inhibit the germination of sclerotinia and the prevention effect is up to 80%.

Proper maintenance. Bacteria and fungi can thrive in warm, moist environments, so it's important to control watering. Small potted varieties should be watered by dipping pots as much as possible.

Try to use drip irrigation or small watering cans for home cultivation in the open field, which can not only save water, but also prevent the occurrence of sclerotinia disease.

Transmission route and pathogenesis of sunflower sclerotinia (rot head): The pathogen overwinters in the soil, in diseased residues and between seeds. In the following year, the temperature rises to more than 5 degrees Celsius, the soil is moist, and the sclerotia germinates to produce ascomycetes, and the ascospores are ejected from the ascospores when they mature, spread by air currents, and invade the host when sunflower germinates.

Overwintering pathogens on seeds can directly damage seedlings. The growth of hyphae on the sclerotia can also infect the base of the stem and cause rot. The growth temperature limit of the fungus is 0 37 degrees Celsius, and the optimal temperature is 25 degrees Celsius.

The temperature limit of sclerotia formation is 5 30 degrees Celsius, the most suitable is 15 degrees Celsius, and the sclerotia is dormant for 3 to 4 months, and the ascomycete disc is generated from the sclerotia. The temperature limit for the formation of the ascomycete disc is 5 20 degrees Celsius, and the optimal temperature is 10 degrees Celsius. It is difficult for the sclerotia to germinate more than 7 cm in the soil, and the germination temperature limit of ascospores is 0 35 degrees Celsius, and the germination is the fastest at 5 10 degrees Celsius, and the fungus can infect more than 200 species of plants in 41 families.

In spring, the stem rot is heavy in low temperature and rain, and the rot is heavy in the rainy disc during the flowering period. Appropriate late sowing, staggered rainy season with light onset. The amount of sclerotinia in the soil of continuous cropping field is large, and the disease is serious.

It is mainly caused by sclerotia germination and infection. The pathogen overwinters in soil, diseased tissues and seeds in a sclerotinia state, and generally lives in the soil for 2 to 5 years. There are two ways to infect it:

First, after the germination of the sclerotia, a hyphae is produced, which directly invades when it comes into contact with the host, and the onset of the disease at the seedling stage and the adult plant stage is this infection mode; The second is that the sclerotia can produce ascospores, and the ascospores are transmitted to the host through wind and rain or insects, and the sunflower rotten plate is caused by the infection of ascospores.

This is because sunflowers do not use very good chemical pesticides and do not protect them very well.

Light sunflowers are short-day crops. But it is not very sensitive to sunlight. For example, under the sunshine conditions of Tianjin, it can bloom and mature normally without special treatment.

Sunflowers prefer full sunlight and have strong phototropism in their seedlings, leaves, and flower discs. In the spring, the sunflowers do not need to be watered too much because the sun is not very strong. In summer, as the temperature rises, the water on the ground evaporates quickly, so it is necessary to use the morning and evening time to replenish the watering in time to ensure a certain amount of water demand.

If you are sure that the water is waterlogged, you can flip the basin on the stool and tap on the edge of the basin, holding the soil ball with your hand. After pouring it out (the soil has poor air permeability and stickiness, it generally does not disperse), put it in a cool, dry and ventilated place, and wait for the soil to dry before planting it back. Current budding period:

Control watering. During this period, the plants are tall, the leaves are abundant, and the water consumption is large, so it is necessary to water in time. Especially under the conditions of high temperature and strong light, supplementary watering is required to avoid wilting of leaves and affect growth.

It is also necessary to avoid excessive drought and water a lot of water.

Do not pour water directly on the leaves, as the small buds that have just been sent out can easily rot. Do not water when the soil is not dry, and do not need to water every day, if the water is sufficient, the branches are hard, if there is a lack of water, the leaves will wilt, I hope that careful observation can grasp the scale of watering because of the particularity in the pot, if the water is too much just in time for the rain, it is recommended to find a thin plastic sheet, cover the soil Sunflower vitality is tenacious, generally do not worry too much, but pay attention not to hurt the roots when turning the soil.

Use a shovel to loosen the soil and drain the pot with both hands, so that the water in the pot will flow out along the small hole under the pot. In addition, the water from the loosened soil will evaporate and dry up with the air. Although the demand for water in sunflowers is not high, it is still necessary to water frequently, because sunflowers like to grow in sunny places, and if the number of watering times is less, the plant will be short of water, so if you want to raise sunflowers well, it is best to water them every week, but in summer, you still need to water them frequently.

1.Rhizolia rot sclerotinia sclerotinia disease,This is the basic type of sclerotinia sclerotinia disease, which can occur from seedling stage to maturity stage, and the harm is serious. After the seed germination, the young shoots and radicles appear water-soaked brown lesions, which cause the young shoots to rot and cannot be unearthed.

The roots and stems of the seedlings turn brown and rot, the leaves turn yellow, and then wilt and die. White mycelium appears at the site of high humidity. 2.

Sclerotinia sclerotinia sclerotinia usually begins at the flowering stage and continues until maturity. The middle and middle and upper parts of the stem of the diseased plant produce withered yellow to brown lesions, nearly oval, expanding to both ends and sides, with multiple layers of concentric rings, and the leaves above the affected part wilt. The inside of the diseased stem is hollow and also contains mycelium and sclerotia.

Diseased plants often bend and crack at the rot of the stem.

The harm is still more serious, for example, it will cause the yield of sunflowers to become low, and it will cause the particles in the sunflower to be not full, and it will also affect the color and yield, and it will also lead to water loss, and the plant will also die, and then the epidermis will also crack, and the edges will also appear brown.

The hazard is to affect the yield of sunflowers, and it is also easy to affect the quality, causing the leaves to shrivel. It will also cause the seed particles of sunflowers to be not full, affecting the final luster, and it is also easy to cause water loss of sunflowers, causing plants to die because of wilting.

Sunflower sclerotinia sclerotinia can occur from the beginning of the seedling to the formation of the flower disc. This condition is most severe after the flowering period, when the flower disc is damaged, water-soaked lesions appear on the back of the flower disc, and the receptacle is brown and soft. In rainy weather, the lesions expand rapidly, which can penetrate the flower disc, turn from the back to the front, and grow a kind of white mycelium, causing the flower disc to rot, so that the grains can not mature, and in severe cases, it can cause the kernels to rot or the seeds to fall off by themselves.

This disease can affect the growth of sunflowers. Moreover, it will also reduce the fruit of sunflowers, the yield is very small, and the size of the melon seeds is not large. And a lot of them are basically empty. will reduce the farmer's yield.

This situation will only cause the growth of sunflowers to be affected, not able to grow very tall and large, and it looks less energetic, there is not much nutrition, and finally it will also affect the fruit of sunflowers, the yield is reduced, most of them are empty shells, and the size of melon seeds is also small.

This will produce some pests and diseases, and there will also be some spots, and it will also expand to the position of the stem, which is not conducive to the yield of sunflowers, and will also cause some bacterial problems.

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