What are the symptoms of yam leaf spot? How to prevent yam leaf spot?

Yellow spots will appear, the epidermis will crack, and a white powder will also be produced, which will slowly expand later. It is necessary to develop pesticides in a timely manner, and also to supplement fertilizers appropriately, to avoid high temperature weather.

The leaves will turn yellow, wither, droop, wither, and some patches will appear; The quality of the seeds should be very good, the soil should be fertile, and more watering, more fertilization, and regular spraying of nutrient solution and poisoning.

1. Symptoms of yam leaf spot:

The affected part is the leaf, the initial leaf surface is greenish to produce yellow spots, and the back lesions are polygonal, pale yellow, without obvious edges, and 3-6mm in diameter. The spots are mostly white to yellow dots, initially under the epidermis, and then the epidermis breaks into a white powder. Later enlargement brownish, with dark brown edges.

The leaves are yellow wilted, and sometimes the lesions form perforations.

2. Environment and conditions for the occurrence of yam leaf spot:

Hyphae and conidia overwinter on diseased carcasses. From July to August, there is a lot of rain, high temperature, lack of fertilizer, extensive management, weak growth, and partial nitrogen fields are prone to disease.

3. Prevention and control methods of yam leaf spot:

1) Implement crop rotation, pay attention to land selection and timely drainage and humidity reduction in case of rain, clean the countryside, and eliminate overwintering pathogens.

2) Foliar spraying with 500 times of 80% zeb wettable powder, 50% carbendazim wettable powder, and 800-1000 times of 70% methyl tobuzine wettable powder at the initial stage of the disease.

Yam is a very common food in daily cooking, yam is very nutritious, often take it can help everyone strengthen the spleen and stomach, but also to lower blood sugar, yam blight is very common and needs to prevent its disease.

The key to yam spot blight is more extensive in seedling emergence and autumn, yam spot blight is the key to damage the leaves, the leaves are dark brown in the early stage of the disease, and the posterior lesions are heptagonal and jujube-shaped or irregular, with a size of 6 10mm, dark brown in the middle, brownish black on the edges, and gray-black hard grain points on the top, that is, the source of the conidia; If the condition worsens, the diseased leaves become withered and the whole plant withers.

When the temperature and humidity standards are suitable in spring, the conidia released by the conidia are blown by the wind to disperse, and the initial infection and several re-infections are carried out, so that the pests and diseases continue to expand.

The pathogen of yam spot blight likes temperature and humidity, and the Mediterranean climate is conducive to the onset of disease, especially precipitation is particularly important for the spread of spores and budding and infecting.

1. Choose land with high terrain and loose and rich soil layer for planting.

2. To prevent replanting in common and seriously ill places, it should be rotated with crops for more than two years.

3. Increase the application of phosphorus and potassium fertilizer and organic fertilizer, prevent partial application of nitrogen fertilizer, high furrow groove, ditch cleaning and drainage, and spray growth vulcanization accelerators such as plant treasure on time, so that the main stem is strong but not vigorous, and grows steadily.

4. Pay attention to the environmental sanitation of the field, completely collect the damage of the disabled during harvest, and do a good job in planting and preventing diseases managed by liquid fertilizer management methods.

Diagnosis of pests and diseases: the key damage to leaves, leaf disease, at the beginning of the leaves to cause dark brown small black spots, and then gradually expand into a size of 6 10mm, heptagon lesions. The lesions are brownish-black on the edges, dark brown in the middle, and there are thousands of black spots on them.

When the disease is severe, the leaves are covered with diseased spots or the diseased spots are connected to each other, causing the diseased leaves to die and die. The pathogen is Dioscorea husk. The conidia of the pathogenic fungus have conidia with leaves, scattered or agglomerate, elevated integument after initial burial, spherical to nearly spherical, dark brown, conidia inverted eggplant stick-shaped, nearly cylindrical, obtuse at the apex, obtuse at the apex, straight or slightly curved, with 2 14 septa.

Pathogenesis: The pathogenic bacteria spend the winter on the disabled body with conidia. The conidia released by the conidia that survive the winter in the second year are carried out for the first and second infusion, and the conidia are dispersed in the field by wind and rain.

Pathogens prefer temperature and humidity standards, and the Mediterranean climate is conducive to the onset of diseases, especially precipitation on spores.

Preventive measures: Choose land with high terrain and loose soil layer for planting. In common and seriously ill areas to prevent replanting, it should be rotated with crops for more than 2 years.

Apply enough manure to the farm's manure. Top application of phosphorus and potassium fertilizers to prevent partial application of overapplied nitrogen fertilizers. Effective water filling, drainage pipes after rain.

In the early stage of the disease, drugs can be sprayed immediately for prevention, and the drugs can be 500 times of 40% polysulfur granules, or 800 times of 60% ultra-fine wettable powder.

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Yam is one of our common ingredients, which can be used to make soup, porridge, or dishes. The cultivation of yam is relatively simple, and the requirements for soil and environment are not high, but in the process of planting yam, the most worrying thing is to suffer from yam spot blight, because this disease is very common, and it will also lead to a decrease in yam yield, so what are the symptoms of this disease? How can I prevent it?

What are the symptoms of yam spot blight?

Yam spot blight mainly harms the leaves of yams, at the beginning, there will be a little brown dots on the leaves of yams, and then they begin to slowly evolve into irregular spots, the shape of these spots is "**brown, dark brown edges, and small black spots on top". Yam is a stem, is grown in the ground, inexperienced people see the yam leaf problem, may not care so much, but once the yam spot blight is serious, it will cause the yam leaves to dry up, and finally the whole plant dies, then it will affect the growth of yam.

The environment and conditions of yam spot blight.

The onset of yam spot blight needs to have a certain environment and conditions, yam spot blight is a conidia on the diseased leaves for winter, and when the temperature rises in the second year, the relative humidity of the air reaches more than 80%, which means that the temperature and humidity are in line with the conditions, it will begin to meristem spores, and then spread by wind and rain.

How can I prevent it?

When the environment and conditions of yam spot blight are understood, there are ways to prevent it in daily life. The incidence of yam spot blight is one due to temperature and the other is humidity, so we need to control these two factors. Usually when planting yams, it is necessary to choose a field that can be high-lying, dry, well ventilated and breathable, do not need to water the yam frequently, usually need to fertilize more, preferably compost and rotten organic fertilizer, do not give too much nitrogen fertilizer.

Although the cultivation of yam is simple, but it can not be taken lightly, if you want to get a good harvest, you need to put in more efforts, usually go to the ground more, look more, once found that there is a disease, the disease will be removed in time.

The symptoms of this disease are that the plants are short, the leaves are yellowish with white-brown spots, and the edges of the leaves are brown, which produces a strong odor.

It is generally found that its leaves will wither, and its growth rate is also very slow, and there are many small insects on it, so that it has no way to grow fruits, and the seedlings will also appear yellow.

The yam leaves will wither and yellow, and there will be some dryness, there may also be rot, there will be some spots, and in serious cases, the leaves of the yam will also fall off, and they will die, which will cause a decrease in yield. Therefore, when watering, it is necessary to water less, do not cause the phenomenon of water accumulation, and turn over the soil more to make the soil more breathable, so as to prevent some lesions.

Yam spot blight mainly harms the leaves, the initial stage of the leaf surface of the leaf is small, the later lesion is polygonal or irregular, the size is 6 10 mm, ** brown, the edge is dark brown, the upper black small dots, that is, the pathogenic conidia. If the disease is severe, the diseased leaves will dry up and the whole plant will die.

This will find that the yellow of the leaf is lighter, and there will be some black, reddish-brown spots attached to the edges, and the yellow next to it will be obvious, and there will be more spots on one leaf, and the whole yam plant will be shrunk and smaller.

Yam mosaic disease, also known as yam streak disease, yam white astringency disease and yam leaf spot, is a major disease of yam. At the beginning of the disease, yellow or yellowish-white spots appear on the foliage with less pronounced edges. After the spread expands, the spots are brown and irregular, and there are no wheel stripes on them.

In the later stages of the disease, the margins of the spots are slightly raised, light brown in the middle, and there are small black spots on them. Some lesions can form perforations, and in severe cases, the leaves will die. On petioles and stems, it grows into round spots.

Yam mosaic disease mainly affects leaves, which can cause plant emaciation, slow growth, and reduce plant yield and quality. Preventive measures: plant strong resistant yam varieties, soak seeds with disinfectant before planting, and reduce the risk of mosaic disease.

It is advisable to plant early, stagger the emergence period and peak period of aphids, and reduce the premature spread of aphids. Timely spraying of new high-lipid film after the emergence of yam can isolate the infection of pathogens, improve its resistance to natural disasters and photosynthesis intensity, and protect the plants from growing vigorously. Strengthen field management, provide sufficient water and fertilizer, promote plant growth, and enhance disease resistance.

And timely cultivation and weeding, completely eradicate weeds in the field and surrounding areas, and reduce field pathogens**. If the symptoms of mosaic disease are found, you can spray the drug in time to prevent and control it, improve the prevention and control effect, help the yam better absorb light energy, and rejuvenate as soon as possible.

When cultivating yams, it is necessary to choose excellent varieties that are disease-free and disease-resistant. When sowing, sowing is done with a double intelligence factor film. After the seeds are dressed with smart factor film, the seeds can be quickly wrapped in an isolation coat to provide the best environment for seed development, and at the same time isolate residues such as pathogens in the soil to improve the germination rate of offspring.

When cultivating yams, early planting should be carried out in time, so that the seedling stage should be staggered as far as possible with the peak period of aphids in the field. At the same time, after the emergence of yam, the bifold intelligent factor membrane should be sprayed in time, which can intelligently filter plant respiratory tract impurities, prevent air pollution, and inhibit virus infection. In addition, it is necessary to strengthen field management, ensure water and fertilizer, timely cultivation and weeding, and reduce field pathogenic bacteria.

Strengthen pest and disease control. Before discovering pests and diseases, spray the intelligent factor film once or twice, which should be careful, uniform and thoughtful, so as to form an intelligent polymer film on the surface of the plant and isolate the pests and diseases. When pests and diseases do not break out, timely spraying of targeted pesticides can improve the utilization rate of pesticide active ingredients, reduce the frequency and amount of pesticides, protect the natural enemies of pests and diseases, and protect the growth environment of plants.

We should change the quality of the land, choose some loose soil, and we should also water more, control it at 2 or 3 times a week, and when we are in society, we should still choose some fertilizers that do not conform to the same as more fertilization, which can prevent mosaic disease.

In order to prevent the occurrence of yam mosaic disease, it is necessary to do a good job in water and fertilizer management, pay attention to the surrounding temperature, clean up weeds in time, clean up those plants that do not grow well, and spray some pesticides regularly to prevent pests and diseases.

Usually water more and fertilize more, buy some pesticides to spray on the leaves, you can also water in the roots of yams, and it can be prevented by turning the soil frequently.

Fertilization must be carried out in the early stage, which can enhance the disease resistance of yam, and pesticides should be used for control in the early stage of pests and diseases.

The yellowish-white spot with inconspicuous edge gradually expands into polygonal brown lesions, light brown in the middle with black dots; After harvesting the product, it is necessary to carry out centralized incineration, reasonable planting, weeding, disease prevention, and reasonable fertilization and watering.

Generally speaking, the mountain has yellowish-white lesions, about 2 5 cm in size, and is light brown in the middle; If you want to effectively prevent and control yam marking, you must do a good job in the management of relevant pests and diseases in the early stage, and spray some relevant agents appropriately.

The lower leaves of the general plant begin to develop the disease first, the lesions are yellow or yellowish-white at the beginning of the disease, the edges are not obvious, the later stage of the disease expands to be polygonal or irregular, the surrounding becomes brown, the middle is scattered with small black grains and slightly prominent, and the lesions are fused in severe cases, and the whole leaf is wide and yellow. The pathogenic bacteria of the disease overwinter on the diseased residue in the form of conidia or hyphae, becoming the source of infection in the following year, and generally occurs in the high temperature and rainy season. The disease was relatively severe in the fields where nitrogen fertilizer was applied to brighten too much.

Prevention and control methods: agricultural control, seed disinfection, sowing with 50 carbendazim 600 times liquid soaking, cultivating strong seedlings; Strengthen field management, timely tillage weeding, loosening soil drainage, increase phosphorus and potassium fertilizer, and reduce nitrogen fertilizer.

1. Symptoms and hazards of yam brown spot disease

Yam brown spot disease, also known as yam gray spot disease and yam brown spot defoliation, is a common disease of yam.

Mainly harms the leaves. At the beginning of the disease, yellow or yellowish-white lesions with inconspicuous edges are formed on the leaf surface, and then gradually enlarged, and the enlargement is often limited by the leaf veins, and is irregular or polygonal, 2 5 mm long. In the later stage, the edge of the lesion is slightly convex, light brown in the middle, and small black dots are scattered, that is, the conidia disc.

In severe cases, the lesion heals, which can lead to perforation or death of leaves, but dead leaves generally do not fall.

Prevention and control methods of yam brown spot disease (1) Choose plots with high terrain and good ventilation for planting. Design the ridge (furrow) direction according to local conditions, pay attention to the density not too large, and avoid canopy between the rows.

2) Do a good job of fertilizer and water management to prevent premature plant aging.

3) Pay attention to ditch cleaning and drainage on rainy days.

4) After harvesting, the sick and residual bodies should be burned or buried deeply, and the soil should be turned deeply.

5) In the early stage of the disease, spraying the agent in time for prevention and control, the agent can be selected with 800 times of 70 methyl tobuzin wettable powder, or 500 times of carbendazim wettable powder, or 500 times of 40 polysulfur suspension, or 500 times of spray gram wettable powder, or 800 times of Deli wettable powder, or 800 times of 800 times of Dasheng wettable powder.

3. Causes of yam brown spot disease

In warm and humid, frequent wind and rain during the growth period, the yam shelf is closed, the ventilation and light transmission conditions are poor, and the air humidity is high, which is prone to yam brown spot disease.

The occurrence and spread of yam brown spot disease are directly related to field temperature and humidity. The suitable temperature for the occurrence of the disease is 25 32, and the higher the temperature, the shorter the incubation period, and the faster the disease spreads. Humidity is the determinant of the outbreak and epidemic of brown spot disease, and the incidence of brown spot disease is often in the rainy season in summer when the relative humidity reaches more than 80%, and the climatic conditions of warmth, fog and heavy dew are conducive to the occurrence of the disease.

Excessive application of nitrogen fertilizer makes the plant grow too vigorously and is also susceptible to disease.

Fourth, the prevention of yam brown spot disease answer 2:

1. Selecting disease-resistant varieties, cultivating disease-free and strong seedlings, and reasonable fertilization and watering can significantly control the harm of yam brown spot disease.

2. The permeability of the planting site should be considered when the yam is furrowed, so as to avoid high humidity between the rows. Even on rainy days, pay attention to ditch cleaning and drainage.

3. After the yam is harvested, the sick and residual body is removed in time and burned in a centralized manner.

5. Yam brown spot prevention and control agents.

1. When the rainy season comes, spray 600 times of 75% chlorothalonil wettable powder or 600 times of 50% carbendazim wettable powder or 800 times of 50% methyl tobuzin sulfur suspension for prevention.

2. Spray 1 000 times of 70% methyl tobuzine wettable powder plus 1 000 times of 75% chlorothalonil wettable powder at the beginning of the disease, or 1 000 times of 70% methyl tobuzine wettable powder plus 600 times of 30% copper oxychloride suspension, or more than 40%? Sulfur suspension 500 times liquid. Spray 1 time every 10 days, 1 2 times in a row.