Tomato late blight prevention and control measures, how to treat tomato late blight?

Tomato late blight, also known as tomato blight, is one of the most common and harmful diseases on tomatoes. Seedlings, leaves, fruits and stems can all be damaged, with leaves and green fruits being the most severely damaged at the adult stage. At the seedling stage, the leaves appear dark green water-stained lesions, and gradually develop to the main stem, causing the petiole and the main stem to appear black-brown and rot, when the humidity is high, the diseased part produces a sparse white mold layer, and the young stem base forms water-stained shrinkage, the seedlings wilt and lodging, and the leaf damage mostly starts from the leaf tip and leaf edge of the lower leaf of the plant, and the initial stage is dark green water-stained lesions, the edge is not neat, and it turns brown after expansion, and the disease spots on the stem are black-brown and rotten, which can cause the plant to wilt.

The lesions are oil-soaked and dark green at first, gradually turning dark brown to brown, slightly concave, the edges are cloud-shaped, the fruit is generally not soft, and when it is wet, white mold grows on the lesions and rots rapidly.

The disease is caused by the infection of pathogenic Phytophthora infestans, the pathogen mainly harms and overwinters on the tomato in the protected area with mycelium, and can also overwinter on the potato, becoming the first invasion at the beginning of the next year, and the pathogen spreads by rain and airflow, and it is only 10 days from the formation of the disease plant in the center of the disease to the full onset of the disease. Warm and moist is conducive to the onset and epidemic, whether there is a water film on the surface of the plant, whether the relative humidity of the air is saturated is the key to the onset of the disease, spring protected land cultivation, large temperature difference between day and night, long condensation time, the plant surface is easy to form water film and water droplets, low-lying terrain, easy to accumulate water in the field, the planting density is too large, partial nitrogen fertilizer, rainy days, large rainfall, long duration are conducive to the onset of disease.

Control methods (1) crop rotation.

Crop rotation with non-solanaceae crops for more than 3 years.

2) Removal of sick and disabled bodies.

During the onset season, the diseased leaves and fruits should be removed in time and buried deeply, and the diseased residues should be removed in time after harvesting.

3) Strengthen field management.

Watering should be carried out on a sunny day to prevent flooding. After irrigation in the protected area, it should be timely ventilated and drained, reasonably densely planted, pruned in time, removed the old leaves of the lower part of the plant, improved the ventilation and light transmission conditions, and increased the air volume under the premise of ensuring humidity.

4) Pharmaceutical prevention and control.

Before the diseased plants in the center of the field do not exceed 1%, the following pesticides should be sprayed immediately: 40% ethylphosphine aluminum wettable powder 200 times, 50% chlorothalonil wettable powder 400 times, 25% Ruifuxyl wettable powder 800 times, 50% promethane wettable powder 1000 times, 64% alum wettable powder 500 times, Pulik water solution 800 times. For every 667 square meters of protected land cultivation, 250 grams of 45% chlorothalonil fumigation agent can be fumigated, or 5% chlorothalonil compound dust agent can be sprayed (1000 grams per 667 square meters).

The above agents are sprayed once every 7 days, and sprayed 3 or 4 times in a row according to the condition.

In the early stage of the prevention and control of tomato late blight, spray with 2 0 0 times the old non-toxic high-lipid film enhancer (emulsion), spray once every 8 to 10 days, a total of 3 to 4 times, and the control effect is 7 0 % 8 0%. Excerpt from the Farmer's Daily

Hello, the solution is as follows:

1. Completely remove the sick and residual bodies in the shed before spraying. First remove the diseased fruits, diseased branches, diseased leaves, etc. of tomatoes in the shed, and then carry out spraying prevention and control of the whole shed, and spray evenly on the top and bottom of the plant and on the ground to completely kill the residual germs and avoid further infection.

2. Prevention and control agents should be cross-used. If the same agent is used continuously for prevention and control, the pathogenic bacteria are easy to develop resistance and can be used (75% chlorothalonil).

3. Other protective measures. Tomato late blight likes a high humidity environment, so while spraying for control, it can also reduce the humidity in the shed through reasonable watering, strengthening ventilation and other measures, especially to avoid dewdrops.

4. Fertilization. You can choose Haihe Weihai Meal Fertile Water-soluble Fertilizer, which is nutritionally comprehensive, containing amino acids, humic acid, polysaccharides, trace elements zinc, boron, etc., to supplement crop nutrition, increase photosynthetic rate, increase yield, improve quality, and enhance plant immunity.

The main measures taken to control tomato late blight are:

First, variety selection.

Disease resistant varieties should be planted, and the disease resistance of tomato varieties commonly used in different regions of China to late blight is very different, which can be selected according to local conditions. Second, agricultural prevention and control.

Tomato and non-solanaceae crops should be rotated for more than 3 years to reduce the source of bacteria. After harvesting, the diseased and disabled tissues are completely removed and properly disposed of in a centralized manner. Fine land preparation, high furrow cultivation, to avoid water accumulation in the field.

Reasonable dense planting, the production of protected land should strengthen ventilation, properly control watering, and use drip irrigation or dark irrigation under the film as much as possible to reduce humidity and avoid high humidity in the shed. Apply plantar fertilizer, increase phosphorus and potassium fertilizer to improve plant disease resistance. Third, pharmaceutical prevention and control.

After the central diseased plant is found, it is necessary to immediately spray the whole plant, and the central plot of the disease should be repeatedly sprayed 3 or 4 times to blockade, and the diseased leaves, diseased branches, diseased fruits and seriously diseased plants should be taken out of the field and burned. The agent can be selected with 50% enoylmorpholine wettable powder 1500 2000 times solution, 69% manganese zinc enyl water dispersible granule 600 800 times solution, downy mildew carb water agent 800 times solution, or 40% methyl pyrin copper succinate wettable powder 700 800 times solution. The protected area adopts the smoke method, and 45% chlorothalonil is applied every 667 m2, 200 250 grams each time, for prevention or fumigation.

Or use the powder spraying method, spray 5% chlorothalonil dust agent per 667 m2 1 kg each time, once every 9 days, smoke and dust generally use good effect in the evening, try to avoid applying pesticides under the condition of sufficient sunlight.

Tomato late blight, generally occurs in leaves, stems, fruits and leaves, most of the lesions start from the tip of the leaf or leaf margin, at first it is a water-soaked green spot, and then gradually expands, when the air humidity is high, the lesion expands rapidly, can spread to most of the leaf or even the whole leaf, and can invade the petiole and stem along the leaf vein, forming brown stripes. The cortex of the stem forms brown streaks of different lengths, and the lesions also grow sparse white frosty mold in humid environments.

Can be used with Frosturea · Manganese-zinc, downy mildew, ethylphosphine aluminum · Manganese-zinc, methae, manganese-zinc, enoylmorpholine, downy mildew · Plague net, silver farry (flumichlor. Dimycocarb), Pulik (downy mildew hydrochloride) and other foliar fertilizer spray control, continuous spraying once every 7 days.

Hello can use 70% ethphosphine manganese zinc wettable powder 500 times liquid, 56% azoxystrobin chlorothalonil 800 times liquid, 50% Fumei double wettable powder 500 times liquid, 75% chlorothalonil wettable powder 700 times liquid, 25% methalonil wettable powder 600 times liquid, 20% benzalene emulsifiable concentrate 300 times liquid, 70% mancozeb wettable powder 500 times liquid, 77% copper hydroxide wettable powder 600 times liquid, 2% Wuyi aqueous solution 150 200 times liquid, every 5 Spray 1 time in 7 days, spray 2 3 times in a row.

1. Properly control watering in the early stage of the disease, pay attention to strengthening ventilation and reducing air humidity in protected land cultivation. 2. Cultivate disease-free healthy seedlings, apply more organic base fertilizers, and pay attention to the reasonable combination of nitrogen, phosphorus and potassium fertilizers. 3. After harvesting, the deciduous tomato late blight is one of the common diseases in tomato planting.

Tomato late blight is a fungal disease. The first stupid day is the first, choose disease-resistant varieties and cultivate disease-free seedlings. If conditions permit, continuous cropping can be avoided throughout the year, and crop rotation can be carried out with non-solanaceae vegetables.

If continuous cropping is allowed, the greenhouse must be closed at regular intervals and the germs must be thoroughly removed before planting. Tomato late blight is prone to occur when the temperature is below 15 and the humidity is higher than 85%, and humidity control is the key. Reasonable dense planting, high ridge cultivation, timely ventilation and dehumidification, reasonable irrigation, timely pruning, and hybridization are all places that need to be paid attention to in the process of tomato planting.

In addition, in the onset season or early stage of the disease, drugs such as pricking, silverhair, methalene, manganese-zinc, and enoylmorpholine can be used in advance for prevention and treatment, and high-concentration drugs can be applied to stem disease. If diseased plants and fruits are found, they should be removed in time and taken to the shed for centralized deep burial to cut off the source of infection. Select disease-resistant varieties, cultivate disease-free and healthy seedlings, sow seeds in a timely manner, plant reasonably densely, scientifically manage fertilizer and water, reasonably adjust temperature and humidity, increase light, and spray silver, phosphorus, aluminum, manganese, zinc and other pesticides for prevention and control.

The late tomato blight is becoming more and more serious, which seriously jeopardizes the economic benefits of the villagers and the planting status of tomatoes. Let's talk about the causes of tomato late blight and how to prevent it.

Cause of tomato late blight

Tomato late blight often occurs in the golden autumn season from September to October, and this disease not only damages the leaves and stems of the plants, but also significantly harms the fruit. The stage of emergence and epidemic of late blight lies in the climatic conditions in which precipitation and environmental humidity are the key factors. The air humidity is about 75%, and the temperature with precipitation, fog and condensation is prone to late blight and the epidemic is fast and the epidemic intensity is high.

It is easy to become popular due to abnormal temperatures such as rain and rain

Tomato late blight is a low temperature and high humidity disease, when the night temperature of the shed is 10 13, the day temperature is 22 24, and the average air humidity exceeds 75% for many days, the disease is most likely to be epidemic. Therefore, in spring and winter, abnormal temperatures such as rain, snow, haze and other weather often occur, and long-term ultra-low temperature and low sunshine in the shed, coupled with the increase of environmental humidity, it is easy to lead to the emergence and epidemic of pests and diseases.

Symptoms of tomato late blight

Diseased tomato plants usually start from the lower leaves, and most of them gradually cause near-ring lesions on the leaves or edges of the leaves, like hot water scalding. The lesions expand rapidly, looming several circles of the same boat wheel pattern, the humidity is large, the leaves are moldy, the weather is dry, and the edges of the lesions become dark brown and cracked. Late blight is very harmful to the fruit, the fruit is not colored before the infectious source disease, after the disease, the fruit rust is wrinkled and uneven, the fruit becomes dark brown, and the material is hard.

How to prevent tomato late blight

It is necessary to strengthen management, increase temperature and humidity, apply phosphorus and potassium fertilizers, and improve the disease resistance of plants.

Improve day-to-day management

Whether the plant is strong or not is the main factor of the plant's disease resistance, so we should start from the cultivation of healthy plants in the production and manufacturing, according to the use of abundant organic fertilizer, control the amount of base fertilizer, and appropriately fill the boron calcium nutrition and other countermeasures, which is conducive to cultivating healthy plants and improving the disease resistance of plants.

Drug prophylaxis can be carried out, and spraying is sprayed when the core disease strain rate does not exceed 1% after the emergence of the core disease strain. The shed is sprayed with 1kg powder of 5% mancozeb smoke, sprayed once in 7 days, or 200-250 grams of 45% mancozeb aerosol agent is placed in 5-6 places, and the closed greenhouse is smoked for one night at dusk, smoked once in 7 days, and lasts 3-4 times.

It can also be prevented by using DuPont E-BaoTech 1000 times liquid, 2000 times fast net liquid, 600 times Badefu liquid, 500 times Jinlei liquid, 800 times Pulik liquid, 60% disinfectant alum 500 times liquid, 58% Radomir manganese zinc 600 times liquid and other sprayers.

Tomato late blight, commonly known as black charcoal and over-fire wind, is one of the common diseases in the planting of tomato in the open field, especially in the rainy season in summer, compared with other diseases, late blight has the characteristics of rapid onset and rapid development. Once the disease occurs in the field, if it is not prevented and controlled in a timely and reasonable manner, it will cause the plants to die in a short period of time, and the yield will be reduced at least, and the harvest will be directly lost.

Harmful characteristics of tomato late blight

Tomato late blight is a devastating vegetable disease that affects tomato seedlings, leaves, stems and fruits. When tomato seedlings are infected, the leaves are infected first, and the diseased leaves appear water-soaked green spots. There is a white mold layer on the edge of the leaf, and the lesion expands and becomes brown, causing the whole leaf to die.

Spreading to the veins and stems will cause the stems to become thin and dark brown, eventually causing the plant to wilt or lodging. At the adult stage of tomato, most of the diseases start from the lower leaves, producing round pale green spots, and under high humidity conditions, white mold will be formed at the affected site. When the fruit is diseased, the oily dark green lesion is formed near the fruit stalk, the lesion is irregular moire, the fruit generally does not become soft, when the humidity is high, a small amount of white mold will grow, and the rot occurs quickly.

Integrated control measures for tomato late blight

Choose disease-resistant varieties: In order to effectively prevent and control late blight, we can choose disease-resistant varieties such as dryland Fan Wang, Cooperative 908, Fan Bao 518, and Baoguan No. 1.

Reasonable dense planting: according to the characteristics of the growth period of different tomato varieties, and combined with the fruiting habits, different planting methods are adopted, and the appropriate planting density is determined according to the soil conditions and variety characteristics, and the blind dense planting must not be done. Reasonable dense planting of tomatoes can improve the ventilation and light transmittance of the field, effectively reduce the humidity of the field, and then reduce the occurrence of diseases.

Crop rotation: To plant tomatoes, it is necessary to avoid continuous cropping and adjacent cropping with Solanaceae crops, and it is best to rotate with other non-host crops, such as cabbage and radish for 3-5 years.

Field management: apply sufficient basal fertilizer, and achieve balanced fertilization, avoid partial nitrogen fertilizer, and appropriately increase the application of phosphorus and potassium fertilizer. According to the characteristics of the variety, it is necessary to prune, top, prune, and remove the old leaves at the bottom in time to effectively reduce unnecessary nutrient consumption and promote the growth of the main stem.

Pesticide prevention and control: from the tomato seedling stage to start disease prevention, generally in the first ear of fruit buds, the first spraying prevention, it is recommended to use 58% methalin manganese zinc wettable powder 500-800 times liquid, 75% chlorothalonil wettable powder 600-1000 times liquid, 64% alum wettable powder 500-1000 times liquid, spray once every 10 days or so, continuous medication 3-5 times, can effectively prevent the occurrence of late blight. When spraying, we should always pay attention to the weather conditions, and spray 3-4 hours before the rain for the best effect.

In the early stage of late blight, timely medication is very important, the selection of frost urea manganese zinc wettable powder 600-800 times liquid, 64% frost manganese zinc wettable powder 1000-1200 times liquid spray, pay attention to the back of the leaf, stem, green fruit should be sprayed, the middle and lower parts of the plant belong to the key spraying area.