What is the reason for the white stuff on the reverse side of the grape leaves?

The reason is that there are a lot of white spots on the back of the leaves of grapes, which may be infected with powdery mildew, after being infected with this disease, there will be a lot of white moldy spots on the leaves, and the spots will gradually increase, which will cause the leaves to gradually wilt, dry and roll, affecting the ordinary growth solution, after finding that the grapes are infected with powdery mildew, the diseased plants need to be pulled out, which can prevent infection, cut off the diseased leaves on the grapes, destroy the leaves in a centralized manner, and spray the grapes with powder rust rather wet powder, carbendazim, methyl tobuzin and other drugs.

I believe that the white mold layer on the back of the leaf is due to the high humidity of the air, and the sporangia and sporangia of pathogenic bacteria.

It is very likely that the plant has pests and diseases. Plant-specific pesticides should be used in a timely manner. Spray evenly on the surface of grape leaves, and do not water during the medication, otherwise it will have no effect.

The white skin of the grapes is fruit powder.

The white frost formed by the condensation of the fructose liquid naturally secreted during the growth of grapes is called fruit powder, and its component is fructose, which is not harmful to the human body, and the better the quality of the grape hoarfrost, the thicker the frost. The fructose powder is also epiphytic with yeasts that play a role in making wine, so it does not need to be removed.

Fruit powder is a biosynthetic natural substance that is completely harmless to the human body. These compounds are insoluble in water, but soluble in organic solvents such as chloroform, so no matter whether they blister with water or wash and rub, they cannot completely remove this layer of hoarfrost from the peel. Legend has it that flour can be used to wash away hoarfrost, but in fact, it does not really wash off hoarfrost, but only changes the structure of hoarfrost or plugs the gap between hoarfrost crystals.

Hoarfrost on grapes is harmless to humans. This layer of fruit powder has a protective effect on the fruit, such as this layer of fruit powder on the surface of grapes can reduce water evaporation, thereby preventing rapid water loss and shrinkage after fruit picking, which has a positive effect on adapting to arid environments. The water-insoluble nature of the powder prevents the formation of a moist environment on the surface of the grapes, thus reducing the infestation of pathogenic bacteria.

The hoarfrost on the surface of the grapes also contains yeast, so homemade wines can be fermented without the addition of yeast.

It should be explained that grapes are not susceptible to insects, and most of the current cultivation is bagged, and the probability of using high concentrations of pesticides is very small, so if it is determined that it is the grapes themselves, there is no need to wash them off.

The white layer on the grape skin, which is called fruit powder, is a wax that protects the skin of the fruit, rich in plant polyphenols, and has anti-cancer effects, but it is often mistaken for pesticide residues and bothered to clean. Grape skin not only has a preventive and positive effect on cancer, cardiovascular and cerebrovascular diseases, but also the natural pigment in the grape skin has a good effect on reducing blood sugar and anti-cancer, and the natural pigment content of dark (purple, red) grapes is higher than that of light (green, white) grape skin, and the function of peeled grapes will be lost a lot.

Grape skin is rich in a polyhydroxyphenolic compound - resveratrol, which has the effects of lowering blood lipids, anti-thrombosis, preventing arteriosclerosis, and enhancing immunity.

Another important substance in grape skin, tannin, has anti-allergic, anti-aging, immune enhancement and prevention of cardiovascular and cerebrovascular diseases.

The anthocyanins contained in grape skin have strong antioxidant, anti-mutation, alleviate liver dysfunction, and protect cardiovascular functions.

Grape skins also have anti-cancer effects, and researchers from the University of Illinois Pharmaceutical University in the United States have found that this substance is more or less present in more than 70 kinds of plants such as peanuts and grapes, especially in grape skins and red wine.

Since most of the grapes on the market have the problem of pesticide residues, they must be cleaned before eating the grapes with the skin. It is best to rinse with water first, with a cleaning product that can effectively remove pesticide ingredients, and wash for more than two minutes. However, it is not advisable to soak in water and salt water, because the soaking of water is easy to promote the penetration of residual pesticides on the surface of grapes into the pulp.

Bordeaux solution, insect repellent use.

Summary. What is the reason for the white stuff on the reverse side of the grape leaf?

Yes, yes. 1. From the top of the slippery or young leaves, the sweet sapphire is red on the tender tip, but many varieties have this phenomenon. 2. On the adult leaves of sapphire grapes, the grape leaves are divided into three columns. This is shown in the figure below. Let's travel.

Summary. Symptoms: White spots on the leaves of grapes may be infected with powdery mildew, which mainly damages the leaves, but also the branches, fruits and other parts.

When grapes are infected with the disease, white mold spots appear on the leaves, the leaves gradually wilt and become soft, and the infected plants begin to weaken, affecting normal growth.

Symptoms: The leaves of the grapes have white spots, which may be infected with powdery mildew, which mainly harms the leaves, but also harms the branches, fruit halls and other parts. After the grapes are infected with this disease, white mold spots will appear on the leaves, the leaves will gradually wilt and soften, and the infected plants will begin to weaken, affecting the normal growth.

Powdery mildew. Prevention and control methods: do a good job of cleaning the countryside, which can greatly reduce the possibility of infection.

In the vigorous period of the disease, you can spray in advance to prevent Xiang's. After the grape is found to be infected, you can spray the drug in time**, you can use the powder rust rather wet powder, you need to spray 2-4 times continuously, and you can also spray it alternately with carbendazim and methyl empty banquet tobuzin to completely remove the powdery mildew of the grapes.

Summary. Hello Dear Hello is a pleasure to serve you according to your questions. The appearance of white spots on the back of the leaves of the vine may be due to the infection of powdery mildew, which is a common fungal disease on the vine, which will form a white powdery substance on the back of the leaves, and in severe cases, it will cause the leaves to turn yellow, wilt and wither, seriously affecting the growth and yield of grapes.

The treatment methods include: 1. First of all, please clean up the fallen leaves and other garbage around the vine to reduce the chance of germs breeding. 2. Kiss can choose copper preparations, sulfur and other fungicides for spraying, pay attention to use according to the instructions, do not overuse.

3. Kiss and then cut off and destroy the infected leaves and branches in time to prevent the spread of germs.

Hello dear to Lu Da manuscript for your service, according to your questions. The appearance of white spots on the back of the leaves of the vine may be due to the infection of powdery mildew, which is a common fungal disease on the vine, which will form a white powdery substance on the back of the leaves, and in severe cases, it will cause the leaves to turn yellow, wilt and wither, seriously affecting the growth and yield of grapes. Methods of treatment include:

1. First of all, please clean up the fallen leaves and other garbage around the imitation vines to reduce the chance of germs breeding. 2. Kiss can choose copper preparations, sulfur and other fungicides for spraying, pay attention to use according to the instructions, do not overuse. 3. Kiss and then cut off and destroy the infected leaves and branches in time to prevent the spread of germs.

Kiss you and follow this to recover.

Live in the order management in the lower left corner of your room for evaluation.

Thank you. Good.

Live in the order management in the lower left corner of your room for evaluation.

When powdery mildew leaves are damaged, a white or off-white layer of silty mold is produced on the surface of the leaves. That is, the hyphae, conidia and meristems of pathogenic bacteria. When the pink spots spread to the entire leaf surface, the leaf surface turns brown and scorched.

The new shoots are damaged, and there are many brown reticulated patterns on the epidermis, and sometimes the branches are not easy to mature. The fruit stalk and panicle stem are damaged, and the texture becomes brittle and easy to break. The fruit is damaged, stops growing, and sometimes becomes rugged.

When the rent is demolished and rainy, the diseased fruit is easy to crack longitudinally, and the flesh is dense and easy to rot. The difference between downy mildew and powdery mildew: (1) The leaf veins of downy mildew are clearly visible, while after being infected with powdery mildew, the leaf veins and mesophyll will be susceptible.

2) Downy mildew is generally on the back of the leaf can be called to the white fungus hug, while powdery mildew is generally on the front of the leaf to the diseased seedling hug. (3) The shape and infection symptoms of downy mildew spores were different from those of downy mildew spores and B. alba, the downy mildew spores were more erect and white in color, while the powdery mildew seedlings were almost like ivory yellow powder, densely spread on the leaves and fruits. Pathogen and occurrence law:

1. Downy mildew is caused by the infection of the genus Uniaxial Mycomycetes of the subphylum Flagellates. The asexual stage of the asexual stage of the cyst is its propagules, and the sexual stage produces oospores. Overwintering in diseased leaves and other diseased tissues with eggs

1. The leaves of grapes are white during growth, and if the leaves are white and moldy, they may have downy mildew. Downy mildew is caused by a pathogen that can endanger the young leaves and shoots of grapes. If the grapes have downy mildew, the diseased leaves need to be cut off, and then the grapes are sprayed with chemicals such as ethylphosphine, aluminum-manganese-zinc or pyraclostrobin**.

2. The leaves of grapes are whitish, if the leaves are powdery, it may be powdery mildew. Improper or improper maintenance of grapes can cause powdery mildew, which will affect the normal growth of grapes. If the grapes have powdery mildew, the diseased leaves need to be cut off and the grapes should be sprayed with carbendazim, methyl tobuzine or Bordeaux solution.

3. There are small white dots on the winding of grape leaves, which may be infested by insects, and the common pest is whitefly. When the grapes are infested by whiteflies, they need to cut off the leaves and burn them in the shed. After cutting off the insect leaves, you can spray the grapes with dimethoate oxide or worm forest agent, spray once in 7 10 days, and spray 3 or 4 times in a row to remove insects.

4. The normal whitish leaves of grapes may be due to the lack of phosphorus, potassium and other elements in grapes. During the maintenance period, if the grapes are deficient in phosphorus and potassium, they need to be fertilized in time. During the growth period, you can apply an appropriate amount of phosphorus and potassium fertilizer to the grapes, and pay attention to the concentration of the fertilizer is not too high, otherwise it will burn the root system of the grapes and affect the growth of grapes in the later stage.

White mold on grape leaves is downy mildew, which is one of the main diseases of grapes, it mainly harms the leaves, often causes a large number of leaves to dry up and fall off, seriously weakens the tree, so that the grape fruit ears can not develop normally, and even can not mature, so that the yield is reduced that year, and the branches are not ripe at the same time, and the branches are not ripe at the same time, and they are susceptible to frost damage, affecting the yield. Sufficient attention should be paid to it.

Immediately after the onset of the disease, it was sprayed with 50 times of manganese zinc of 50 Ruifu. After application, Ruixin mold immediately enters the plant and is transported to various parts with water to kill the germs. Mancozeb remains on the surface to prevent the invasion of germs, and the protective effect of this drug is especially obvious during the peak of infection.

At the same time, manganese and zinc are the elements required for grape growth. However, the spraying of manganese zinc with too many times or long-term use year by year will cause drug resistance, and it should be used in combination with other protective agents, and it should be used 2-3 times a year.

Causes: The disease is a fungal disease, and the pathogen is Elexicona grape. The pathogen overwinters in the affected tissues or bud scales with mycelium, produces conidia in the spring of the second year, spreads through wind and rain, penetrates the epidermis for primary infection, and can be re-infected multiple times during the growing season.

Dry summers and sleepy summers are warm and humid and muggy, and the weather is conducive to the occurrence of powdery mildew. Generally, the onset begins in June, reaches its peak from mid-to-late July to early August, and stops in September and October.

Pattern of onset. The fungus overwinters in the affected tissues or between the scales of the buds with mycelium. In the second year, when the conditions are suitable, the conidia are generated, and the conidia are transmitted by the air current, and after the leaves damaged by grape powdery mildew enter the host tissue, the hyphae spread outside the epidermis, and the suction device extends into the host epidermal cells to absorb nutrients.

The optimal temperature for conidia germination is 25 to 28 degrees Celsius, and germination can occur at low relative air temperatures. Grape powdery mildew generally begins in mid to late June, and gradually reaches its peak in mid-July.

Dry or sultry, cloudy weather in the summer is conducive to the occurrence of diseases. Grapes are planted too densely, with too many branches and leaves, and poor ventilation is conducive to disease.