Good evening! What are the measures for the comprehensive prevention and control of tomato leaf curl

If it is determined that it is a virus, it can be solved, two or three times. Spray as required.

1. Temperature control: The temperature is controlled between 15-28 degrees Celsius, and good ventilation is maintained. 2. Reduce fertilization

Apply a thin fertilizer every 20-30 days. 3. Disease prevention and control: disinfect seeds and soil, and spray potassium permenate solution during growth.

4. Watering too much: drain the stagnant water, and water it every 5 days or so in the later stage.

1. Temperature control

Tomato leaf curl disease mostly occurs in the summer of high temperature and humidity, when the temperature is higher than 35 degrees Celsius, the leaves will gradually curl, at this time it is necessary to cool down, maintain good ventilation, and control the growth temperature of tomatoes between 15-28 degrees Celsius.

2. Reduce fertilization

Excessive fertilizer is applied during the growth of tomatoes, leaf curling will also occur, and during the cultivation process, a thin fertilizer can be applied at intervals of 20-30 days, and the fertilizer should be diluted with water, and cannot be sprinkled directly on the roots of tomatoes to avoid burns.

3. Prevention and control of diseases

Tomato leaf curling may be the result of a viral disease, which can damage the stems and leaves of the plant after the onset of the disease, in order to prevent disease, the seeds and soil should be disinfected during the planting process, and the tomato should be sprayed with a solution of potassium high fernate during the growth period.

4. Watering too much

Tomatoes are afraid of waterlogging, too much watering during breeding, will make the root system rot, the leaves gradually curl, at this time to discharge the water, the later can be watered once every 5 days or so, in the rainy season to dig a trench in the field to drain, so that the tomatoes grow normally.

As the temperature rises, especially in summer, the temperature is relatively high, and the pesticide damage will occur if you are not careful when spraying, once the drug concentration is too large, the pesticide damage occurs, the surface of the leaf will change color or have spots, and the leaf will also curl upward.

If the crop uses too much fertilizer, it will lead to an increase in the concentration of soil solution in the root system, which will hinder the absorption of water by the root system, resulting in water shortage in the leaves, causing the leaflets to flip and roll up.

For example, when too much ammonium nitrogen fertilizer is applied in the soil, the midribs of the small leaves on the mature leaves are raised, and the leaflets show an inverted bottom shape, and the leaves appear to turn up and roll. Especially in saline-alkali areas, when the salt concentration of soil solution is high, it is also easier to curl the leaves upward.

When the plant is deficient in calcium and some trace elements, it can cause leaf curling symptoms. These are physiological leaf curls, often distributed on the leaves of the whole plant, not accompanied by the symptoms of bright veins mosaic leaves, often occur on the leaves of the whole plant, it is recommended to use Yanwo chelation in the trace element water-soluble fertilizer, rich in a variety of nutrients, not antagonistic, good absorption, effectively alleviate the physiological diseases caused by the lack of nutrients in vegetables, promote the growth of vegetables, and improve the stress resistance of vegetables.

Vegetable topping is too early, which is easy to breed bacteria in the axillary buds, and the phosphoric acid in the vegetable leaves has nowhere to be transported, resulting in the first aging of the lower leaves and the shrinkage of the leaves.

If the crop is planted too early and pruned too heavily, it will not only affect the development of the underground root system, limit the quantity and quality of the root system, but also make the aboveground part grow poorly, affect the normal growth and development of leaves, and induce leaf curling.

Viral diseases can generally be transmitted by aphids, whiteflies, etc. When the plant has a viral disease, all or part of the leaves will appear from top to bottom and curl upward, and at the same time, the leaves will fade green, become smaller, shrink, clump and other phenomena, and in severe cases, there will only be leaf veins and no mesophyll, which is mostly manifested in the heart leaves and upper leaves.

Using a plant-derived product and spraying it once will cure more than 70%, and it will cure all of it after two or three times.

Tomato yellowing leaf curl virus disease.

It may be caused by high temperatures and drought. It can also be a viral disease. It depends on what season and under what circumstances?

1: Physiological leaf curling. Symptoms:

Before and after the tomato is harvested, the leaves of the first ear are slightly curled, or whole: the leaves of the plant are curled into a cylindrical shape and become brittle. This is mainly due to high temperatures and droughts, and the stomata of tomato leaves are closed.

Control measures: drought resistance exercise after planting and before fruit setting; After fruit set, water and fertilize in a timely manner and cover the shade net, so that the day is covered and the night is uncovered, and the cloudy day is not covered.

2: Deficiency of nutrients. Symptoms:

Phosphorus deficiency is manifested as purple-red on the back of the leaves, small brown dots appear on the leaves, the lower leaves roll up, the old leaves turn yellow, and the tips of the leaves are black-brown and die. Generally, low temperature at the seedling stage will affect the absorption of phosphorus, and the soil is acidic or compact, which can be solved by applying phosphorus fertilizer to the soil or spraying potassium dihydrogen phosphate. When magnesium is deficient, in the first inflorescence stage, the old leaves in the lower part of the diseased plant lose green, and yellowing occurs between the leaf veins, and then expands upwards to form yellow-spotted leaves.

In severe cases, the leaves are stiff or the leaf margins are rolled up, and necrotic spots or brown patches appear between the leaf veins. The control method is to increase the application of nitrogen, phosphorus and potassium vegan fertilizer or foliar spray of magnesium sulfate 50 100 times the solution.

3: Hormone damage. Symptoms:

The symptoms of 2,4-D pesticide damage are bent leaves or growth points, new leaves cannot be normal, leaf margins are twisted and deformed, stems and vines are convex, and the color becomes lighter. The symptoms of other hormones such as anti-drop hormone and chlormequat are generally milder than those of 2,4-d. Prevention and control measures:

Strictly control the concentration of spraying hormones, generally the concentration of early maturing varieties is 15 mg kg, the concentration of medium ripening varieties is 20 mg kg, and the concentration can be lower when the temperature is high. Do not spray hormones on growing spots or young leaves when spraying. After the occurrence of hormone damage, some fertilizers can be applied to promote growth, such as natural brassin, 3000 times liquid can be used for prevention and control.

4: Tea yellow mite harm. Symptoms: Narrowing, stiff and erect leaves, shrunken or twisted deformities, and finally baldness. The control agent can be sprayed with 3000 times of afudin, or 20% mite 2000 times of liquid spray, sprayed once every 6 7 days, and sprayed 2 3 times in a row.

5: Viral disease hazards. Symptoms:

The virus is transmitted to tomatoes by aphids and whiteflies after feeding on the sap of leaves. The susceptible plants are short, the leaves are curled and clustered, and the leaves only have leaf veins and no mesophyll when they are severe, and the high temperature and drought weather are conducive to its spread and harm. Prevention and control measures:

In addition to the selection of antiviral varieties and the implementation of crop rotation to reduce the source of primary infection, in the early stage of the disease, potassium permanganate can be sprayed 1000 times liquid, and the treatment of viral diseases and soft rot and other diseases, can also be added in 50 kg of water A (K) 100 grams, 50 grams of green Fenwei and a net 25 30 grams, made of mixed liquid spray control, spray 1 time every 6 7 days, spray 2 3 times.

6: Wind chill hazards. When ventilating in the shed, the ventilation is too rapid and too fast, the outdoor cold air and the indoor warm air exchange is strong, the tomato leaves can not adapt to the drastic change of the environment, it is easy to cause the tomato leaves near the vent to curl, under normal circumstances, as long as the gradual release of the wind and refining seedlings, the leaf curling phenomenon will not occur.

Excuse me; If there is no hormone spraying. Please spray Ye Ling, it can return to normal in 10 days.

You can log on to the China Plant Protection Network to inquire about relevant technologies, cultivate and weed, water and top dressing in the greenhouse tomatoes in a timely manner, and reduce the field humidity in time, spray to promote the growth of the main shoots, promote the differentiation of flower buds, and improve the disease resistance of plants.

It should be late blight can be referred to.

Leaf curl virus disease, diseased plants almost stopped growing, the infection is fast, spraying three or five times of medicine will be cured, search for root knot nematode on the Internet to find biological pesticide 30% suspension willow.

According to the analysis, it is likely that the tomato is physiologically curled. The control method is to improve the stress resistance of tomato through timely irrigation and strengthened management, which can alleviate the symptoms.

Symptom: The leaves are rolled up longitudinally. The severity of leaf curls varies greatly, with some curling only the lower or lower middle leaves, and the entire plant.

When leaf curling is severe, the leaves become thick and brittle, which has an impact on yield.

Tomato leaf curling mostly occurs before or during the harvest of the fruit.

Causes: Soil drought, or poor root development, damage, weak water absorption ability, high temperature plant leaf transpiration, more water loss. In order to reduce water loss, the leaves of the plant are curled, which is a physiological protective phenomenon.

If the wind is too rapid in the production of tomatoes in greenhouses, leaf rolling will also occur.

Excessive application of nitrogen fertilizer, especially the lack of trace elements such as iron and manganese in the soil, will also roll the leaves. This kind of leaf curling is often accompanied by symptoms such as yellowing and purple of the leaves.

If the plant is pruned, pruned, and topped too early and too heavy, the phosphorus absorbed by the root system has nowhere to be transported, and will accumulate in the lower leaves, making it harden and curl.