What are the manifestations of tomato downy mildew disease and can it be treated?

The main symptoms of tomato downy mildew are: the main occurrence of greenhouses, seedling stage, adult stage can occur, mostly from the upper part of the seedling or outside the wound disease, the disease part is gray-brown, rotten, and the surface has a gray mold layer. At the adult stage, the leaves are diseased, starting from the leaf edge to the inward to produce light brown "V" shaped lesions, water-soaked, and gray mold layer on the surface of the dark and light ring pattern, and gray or gray-green mold layer is also produced on the back of the lesion when wet, and the leaves gradually die.

When the fruit is diseased, the pathogen is mostly infected from the residual petals, receptacles, etc., and gradually expands to the fruit, and the fruit pedicle is gray-white water-soaked soft rot, resulting in gray to gray-brown mold layer.

The disease is mainly caused by high temperature and humidity, mainly timely ventilation, the temperature is kept at 25 -30 in the morning during the day, the temperature is kept at 20 25 in the afternoon, and the temperature is kept between 14 -18 at night.

This downy mildew is not a major disease, ** it is recommended that you go to the local agronomic station to ask, this is the advice of Shouguang innovative seed **** agronomist to you, I hope it will help you.

It is mainly related to temperature and humidity, and high temperature and high humidity are conducive to the onset of the disease, among which humidity is an important factor affecting the pathogenesis. At a temperature of 22, as long as there is a water film on the leaf surface for 4 hours, the disease can be induced. If the temperature in the shed is 20 25 and the relative humidity is greater than 90%, leaf mold can start from scratch within 3 days, and it can occur seriously.

Weak light is conducive to the occurrence of leaf mold.

In the main shed, the seedling stage and the adult stage can occur, and the disease is mostly from the upper part of the seedling or outside the wound, and the diseased part is gray-brown, rotten, and there is a gray mold layer on the surface. At the adult stage, the leaves are diseased, starting from the leaf edge to the inward to produce light brown "V" shaped lesions, water-immersed, and gray mold layer on the surface of the dark and light ring pattern, ** is okay, of course, it also needs to depend on the condition. Spray 150 times of mold, once every three days, for two consecutive days.

Tomato downy mildew mainly harms the leaves, with water-soaked lesions on the back of the leaves, black mold growing on the lesions when wet, and dry up the whole leaves when severeControl methods: (1) Choose disease-resistant varieties.

The main ones are Changchun Mithorn and Jinchun No. 3. (2) Ecological prevention and control. The temperature of the control shed is stable within 25---30, and the relative humidity of the air is maintained at 60% and 70%.

Water less at the seedling stage, water a little water, and water at the right time during the melon stage. If the occurrence of downy mildew is severe, you can carry out high temperature (45) stuffy shed for 2 hours, and then slowly let the wind out, choose a sunny day high temperature stuffy shed, and stuffy 2 or 3 times in a row, which can effectively control the occurrence of disease. (3) Drug prevention.

75% chlorothalonil 600 times solution (or 70% mancozeb 500 times solution, 80% ethyl phosphorus aluminum 500 times solution, 25% chloride mold 800 times solution, 50% ethyl phosphorus aluminum manganese zinc 500 times solution, 58% manganese zinc liquid 600 times, 72% Kelu 600 times solution, Prix 600 times solution, 69% Anker manganese zinc 1000 times liquid, 2000 times fast net liquid, 70% Baidefu 600 times liquid, 20% gram 1500 times liquid, bacteria immediately killed 500 times liquid)+The new high lipid film is 800 times the liquid, sprayed 1 time every 5 7 days, and sprayed 2 3 times in a row. If it is rainy, it is not suitable to spray, and 20% chlorothalonil fog agent can be used.

Tomato downy mildew control methods:

1.Ecological control: regulation of temperature and humidity.

Keep 25 -30 in the morning, 20 -25 in the afternoon, 15 -20 in the first half of the night, and 10 -15 in the second half of the night. The practice is to release the air in time when the temperature reaches 30 in the morning, so that the temperature in the shed is kept at about 25, and the air outlet is closed in time when the temperature is about 23 in the afternoon. In the evening, when the temperature in the shed is 20 -18, put down the straw curtain to keep warm; Proper moderation of watering, strictly prevent watering, watering should be selected in the morning on a sunny day, the night before watering with a smoke agent to fumigate the shed once, do not water during the onset period, and pay attention to moisture drainage after watering.

Strengthen ventilation management to reduce humidity in the shed. The practice is, after the curtain is drawn in the morning, the air is let out for about 20 minutes, the fog in the shed is drained away and then closed, and the temperature in the shed rises to 30 and then the air is exhausted to reduce humidity. This method has a better effect of dehumidification.

2.Scientific treatment of diseased plants: Diseased plants, diseased leaves, diseased branches and other diseased residues should be taken out of the shed in time to burn or bury. When carrying out agricultural operations, the healthy plants should be operated first, and then the diseased plants should be operated, and the diseased plants should be washed before doing other work. Eliminate man-made infection.

Tomato leaf mildew is also known as black hair disease in some places, and it is also one of the common diseases of tomatoes, which affects the quality and yield of tomatoes in severe cases.

So, what are the symptoms of tomato leaf mildew? What medicine is good for tomato leaf mold? What are the prevention and control methods? Let's take a look.

Tomato leaf mildew symptomsTomato leaf mildew is mainly harmful to leaves, and can also damage stems, flowers and fruits in severe cases.

In the early stage, irregular or oval yellowish fading spots appear on the front of the leaf, the edge is not obvious, and the back of the leaf appears gray-white to black-brown dense mold layer, and later becomes purple-gray or dark gray to black or yellow-brown; When the humidity is high, the mold layer can also grow on the surface of the leaves.

With the expansion of the disease, the leaves are gradually curled from the bottom to the top, and the lower leaves of the diseased plant are first diseased, and then gradually spread upward, so that the whole leaf is yellow-brown and dry, and the whole plant can be curled when the disease is severe.

Diseased flowers often die before fruit set.

Stem infection symptoms often resemble those of leaves.

The fruit is infected, and round to irregular black-brown patches are produced near the fruit pedicle or on the fruit surface, hardened and depressed.

What medicine is used for tomato leaf mildew is not the same as the resistance of leaf mildew in various places, it is recommended that flusilazole, difenoconazole, propiconazole, etherstrobin, iprodione, chunleimycin, polyantimycin, pyraclostrobin, etc., choose one or two, and alternately use pesticide ingredients.

It is better to spray with silicone additives.

Hit it all over and through. In the case of greenhouses, humidity should be controlled, and sterilizing fogs should be used to control the condition on rainy days.

Prevention first, comprehensive prevention and control.

Use pesticide ingredients alternately, and do not use the same pesticide ingredients consecutively.

This is the principle of crop protection.

Tomato leaf mildew control method 1Choose disease-resistant varieties.

2.Remove the diseased residues of the plants in time, take them out of the field, and burn them or bury them deeply.

3.Reasonable crop rotation: Crop rotation with non-solanaceae crops for more than 2-3 years to reduce the number of pathogens in the soil.

4.Seed disinfection: Seed treatment is carried out by soaking seeds in warm soup, and after cleaning, drying, germination, and sowing are carried out.

5.Field management: avoid partial application of nitrogen fertilizer, increase the application of phosphorus and potassium fertilizer, prevent vigorous growth, and enhance plant disease resistance; Clean up the lower old leaves and yellow leaves in time, which is conducive to ventilation and light transmission; The greenhouse planting area is ventilated in a timely manner, watering is controlled, and moisture is discharged in time after watering.

6.Pesticide control: Pythium, polyantimycin, iprodione, difenoconazole and other agents can be used for whole plant spray control, focusing on spraying the back and middle and lower leaves of the leaves.

1. Choose disease-resistant varieties. 2. Advocate the use of ecological prevention and control, focusing on controlling temperature and humidity, increasing light, and preventing high humidity and low temperature. Strengthen water management, watering in the morning, watering at the seedling stage, watering thoroughly, not watering before flowering, watering lightly when flowering, watering after fruiting, draining moisture immediately after watering, and try to make the leaf surface not condensation or shorten the condensation time.

3. When cultivating in the open field, remove the stagnant water in the field in time after the rain. Increase the application of fully decomposed organic fertilizer, avoid partial application of nitrogen fertilizer, increase the application of phosphorus and potassium fertilizer, timely top dressing, and foliar spraying. The planting density should not be too high, pruning and tying the vines in time, and the lower old leaves should be appropriately removed after the plant is set with fruit.

Special chemical fertilizers should be used, because only in this way can the growth of crops be better guaranteed.

Biological fertilizer was applied to the soil, 5406 kg of bacterial seed powder per mu was used before planting, and 10-15 kg of cake fertilizer was mixed into the planting ditch, or other biological fertilizer was sprinkled on the soil. After planting, the ground is sprayed with 300 grams of "Baode" soil biological bacteria inoculant, or 500 grams of biological pleiotropic qi, which can inhibit and reduce the disease.

If the onset of the disease has begun, it is necessary to spray 2000 times of 25% amisida suspension, or 4000 times of 30% Aimiao EC, or 1500 times of 50% Kaiser water sprinkler, or 3000 times of 96% Tianda Oxalin, or 600 times of 60% anti-mildew Bao ultrafine powder, etc., respectively, mixed with 1500 times of Tianda silicone + 600 times "Tianda-2116" liquid. The above liquid medicine is used alternately, once every 7-10 days, sprayed 2-3 times continuously. In case of cloudy and snowy weather, use dust or fog agent instead.

1. Scab disease: It occurs in the green fruit stage, and water-soaked green spots appear on the fruit surface, and brown lesions appear in the later stage. 2. Tendon rot:

The color of the peel is uneven, and more organic fertilizer should be applied during the breeding process. 3. Spot blight: caused by fungi, splashed on the leaves of plants by rainwater.

4. Black spot disease: Lesions appear on the fruit surface, and black-brown mold grows.

1. Scab disease

Tomato scab disease is serious, generally occurs in the green fruit stage, there will be water-soaked green spots on the fruit surface, gradually spread outward, brown lesions will appear in the later stage, the bad fruit should be cut off in the early stage of tomato disease, and sprayed with copper hydroxide agent.

2. Tendon rot:

After the occurrence of tendon rot of tomatoes, the color of the peel is uneven, the inside is black and hard, there are green and red, in the process of breeding tomatoes, it is necessary to apply more rotten organic fertilizer, improve soil conditions, pay attention to apply less nitrogen fertilizer, otherwise the tomato will rot.

3. Spot blight

After the tomato is infected with spot blight, there will be a lot of brown round spots on the fruit, the edge of the leaf is dark brown, the disease is caused by the fungus, the rain splashes on the leaves of the plant, the leaves close to the ground are the first to disease, the yellow leaves can be cut off, and then the tomatoes are sprayed with chlorothalonil.

4. Black spot disease

Tomato black spot disease mainly occurs in the fruit that is about to ripen, there will be round or oval lesions on the fruit surface, and black-brown mold will appear when the humidity is too high, and it generally occurs in the high temperature and rainy season, and can be sprayed with chlorothalonil and difenoconazole.

Tomatoes are fruits and vegetables. It is eaten sweetly, loved and also has various vitamins, which also has great advantages for the body, so the growing area in our country is very large, and in order to ensure that you can eat on it in all seasons, many plantations are planted in greenhouses. If the effect of planting is natural, tomatoes often encounter some diseases, and if they cannot be solved, then the production is naturally affected, what are the common diseases?

1.Hollow heart disease.

When tomatoes have such a disease, the symptoms are not very noticeable, so many kinds of builders are neglected, which reduces a lot of income. If you want to distinguish between the disease, you should fix it yourself. Most hollow diseases occur during the winter months, and it is susceptible to this disease if there are large temperature changes or malnutrition.

When planting, it is necessary to pick a few pinch. Once it is pressed, it should be a disease because it is already empty, it will fertilize in time while the temperature is controlled and it can grow in a later time.

2.Rumor. This disease is more common.

After the onset of the disease, there will be scars similar to tomatoes. Since the symptoms are obvious, it is easy to distinguish. When you start to start, the local color will become abnormal, then the color will slowly deepen, and finally the scar will turn brown and can be scattered inside, but only one part of the disease is like this, the rest is normal.

Pay attention to the use of nitrogen fertilizer, not too much or too small, after the onset of the disease, while spraying the potassium dihydrogen phosphate solution.

3.Type. This disease is mainly due to the environment, if it is managed regularly, if pollination is poor, it will become a problem for development, plus temperature changes, and the development of tomatoes will be greater, then it can easily lead to the occurrence of this disease.

At the bottom of the tomatoes, the bottom of the tomatoes will have smoke spots, and then gradually dry out, and finally the whole fruit will be damaged, so it is very important to manage it, and it can also be prevented in advance You can use it. Potassium phosphate prophylaxis**.

4.Grey. This spreads very quickly, so it is also a more harmful disease.

Once you find it, you have to deal with it immediately. Most of them are caused by this disease. At the onset of the disease, the tomato will turn brownish-yellow and then become very soft, eventually causing the fruit to fall.

If you find the disease, you have to remove the diseased tomato and bring it to the site, otherwise it will cause harm to other fruits, and then use **people**, especially the onset of the disease, must be sprayed in place.

The above four are the more common diseases, and it can be seen that these damage is very large, which is also the most undesirable and want to avoid these diseases. Learning, scientific management in planting, to give tomatoes can grow in the best environment, so that they can grow and develop better and effectively resist diseases.

The common pests and diseases of tomato are mainly early blight, gray mold, and leaf mold. Insect pests such as viral diseases include whiteflies, aphids, etc. Prevention and control methods, strengthen soil improvement, often the irreversibility of soil problems, resulting in a high incidence of diseases year after year, and disease-resistant seeds should be selected, and the seeds should be sterilized and sterilized.

Install insect nets and apply appropriate foliar fertilizer to accelerate nutrient supplementation.