What is the prevention and control method of tomato bacterial leaf spot symptoms?

Symptoms: Tomato bacterial leaf spot disease mainly affects leaves, stems, flowers, petioles and fruits. The leaves are susceptible to the disease, producing dark brown to black irregular spots, 2 4 mm in diameter, with or without yellow halos around the spots.

The petioles and stems have similar symptoms, producing black spots but no yellow halos around the lesions. The lesions are easy to connect into plaques, and in severe cases, a section of the stalk can turn black.

Prevention and control methods: strengthen quarantine to prevent the introduction of infected seeds into non-epidemic areas; Establish disease-free seed fields and use disease-free seedlings; Crop rotation with non-Solanaceae vegetables for more than 3 years. Seed treatment.

Soak the seeds in 55 warm water for 30 minutes, or soak the seeds with acetic acid solution for 24 hours, rinse off the liquid with water after soaking, and then promote germination after a little drying. Pharmaceutical prevention and control. In the early stage of the disease, 400 500 times of 77% copper hydroxide wettable powder, or 600 times of copper hydroxide water dispersible granules, spray once every 10 days or so, and spray 3 or 4 times in a row.

Use of agents: the first choice can kill 2000, followed by streptomycin.

Concentration: 20001000 times the solution, 3000 times streptomycin 4000 times the solution.

Control period: leaf spraying begins at the seedling stage, and the second time after planting the seedlings, and the third time after the interval of 7 days and 10 days, can effectively prevent and control the occurrence and spread of tomato bacterial leaf spot.

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Control methods: Agricultural control: remove weeds at the edge of the field and dead branches and rotten leaves after harvest, and destroy them in a centralized manner to reduce the source of mites.

Pesticide control: the insect is eliminated in the spot occurrence period. 73% alkyne mite 1500 times liquid spray; 25% acaricidal 1000 1500 times liquid spray.

Cyhalothrin EC 4000 times liquid spray. Bifenthrin EC or 5% Nisolan EC 3000 4000 times liquid spray. The above agents are sprayed once every 7 10 days, and 2 3 times in a row.

At the beginning, yellow-green spots with inconspicuous edges appeared on the front of the leaves, gray-white mold layer appeared on the back of the leaves, and the posterior mold layer became light brown to dark brown. When the humidity is high, the mold layer can also grow on the surface of the leaves. The disease often starts from the lower leaves, and gradually spreads upward, and when the disease is severe, the mold layer is covered with the back of the leaves, the leaves are curled, and the whole leaves are yellow-brown and dry. Similar lesions can also be produced on the young stems and fruit stalks, and the flowers are easy to fall off.

The fruit is diseased, and black round or irregular patches are formed near the fruit pedicle or on the fruit surface, hardened and sunken, and cannot be eaten.

The front of the leaf is irregularly shaped, oval pale yellow and greenish spots, the edge of the lesion is not clear, the leaf dorsal lesion is grayish-white, black-brown dense mold layer, and the mold layer becomes dark gray and black-brown in the later stage.

Tomato leaf mildew mainly damages leaves, and in severe cases, it also damages stems, flowers and fruits. At the beginning, yellow-green spots with inconspicuous edges appear on the front of the leaves, gray-white mold layers appear on the back of the leaves, and the posterior mold layer becomes light brown to dark brown. The disease usually occurs from the lower leaves, and gradually spreads upward, and when the mold layer is not on the back of the leaves, the leaves will bend, and the whole leaves are yellow-brown and dry.

The back of the leaves will appear grayish-white mold, and the leaves will be yellowish, and there will also be inconspicuous spots, and the leaves will roll up and be very dry.

The disease mainly damages tomato leaves, and sometimes also flowers and fruits. The onset of leaves is initially the appearance of irregularly shaped or oval yellowish yellowish patches on the front of the leaves, and the edges of the lesions are not clear. Leafy dorsal lesions are covered with grayish-white to black-brown dense mold layers.

Later stage, the mold layer changes dark gray to black-brown. When the humidity is high, a mold layer can also grow on the lesions on the front of the leaves. The diseased plant spreads from the lower leaves upwards until the whole leaf becomes yellow-brown and withered.

In severe cases, the leaves of the whole plant are curled. The buds are damaged and die before fruit set. The diseased fruit produces round to irregular lesions near the fruit pedicle, and the lesions are hardened and depressed.

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.

Manhattan Hou Mentor No. 6 Fungicide.

Prevention and control methods: Agricultural prevention and control: do a good job in field management, cut off the tender shoots and eggplant fruits of the damaged plants in time, and clean the farm; After harvesting, the residues are uprooted to reduce the source of insects.

Sexual attractant moth: use sexual attractant to lure male moths, the general dose is 100 micrograms, and the trap is set to one every 30 meters, which can be used to trap and predict insect conditions. Pharmaceutical prevention and control.

In the larval hatching period and before the borer is infested, spray and control, you can choose 50% phoxanthion EC, or 50% pine borer EC, or 40% acemethamidophos EC, or 80% trichlorfon soluble powder 1000 times each, or deltamethrin EC, or 20% pyrethrin EC, or cyhalothrin EC, or bifenthrin EC, or 5% Leferin EC 2000 3000 times liquid spray.

77 can kill 400-500 times of wettable powder, 2000 can kill 600 times of dry suspension, 20 thiopyridoxim (Longcobacterium) suspension 500 times of liquid, 14 copper ammonia aqueous 300 times of liquid for spray control, spray once every 10 days or so, spray 3-4 times.

Bacterial copper-based fungicides can be used, such as Kede3000, which is composed of 46% copper hydroxide water dispersible granules.

There is a medicine in Shouguang, which is called holding it steadily, and it is OK to use both sides in a row.

The first consideration for the prevention and control of tomato gray leaf spot is to select disease-resistant varieties. At the same time, the following measures are applied:

First, agricultural prevention and control.

Crop rotation is practiced. rotation with non-Solanaceae crops such as cruciferous and cucurbitaceae; Strengthen field management. When planting, sufficient basal fertilizer was applied, and organic fertilizer, phosphorus and potassium fertilizer were added to enhance the host's disease resistance. If conditions permit, drip irrigation or dark irrigation under the membrane should be implemented as far as possible, and ventilation should be strengthened to reduce microclimate humidity; After harvesting, the diseased residues should be removed in time, burned in a centralized manner, and the soil should be turned deep in combination with land preparation to reduce the source of overwintering bacteria.

Second, chemical control.

At the beginning of the disease, spray 600 times of 75% chlorothalonil wettable powder, or 500 times of 40% closulfidan wettable powder, 400 500 times of 77% copper hydroxide wettable powder, 800 times of 80% mancozeb wettable powder, and 500 times of 50% thiophanate-methyl sulfur suspension, and control once every 10 days, and 2 3 times in a row.

Tomato leaf spot disease only harms the leaves, the leaves are covered with dark round or irregular round small spots at the beginning of the disease, and then expand along the leaf veins to the periphery, showing irregular tomato gray leaf spot disease only to harm the leaves, the initial leaf surface is covered with dark round or irregular round small spots, and then expand along the leaf veins to the surrounding areas, showing an irregular shape, and the middle gradually fades to gray-white to gray-brown.

Tomato leaves are disease-shaped, and the middle part fades to grayish-white to grayish-brown.

Method 1: Sesame Spot Disease, also known as Brown Spot Disease. Difenoconazole, or copper thioxenate, or copper thiasen, or prochloraz, or pyraclostrobin, or pyroxystrobin, or zeb, or propylzeb with amino acid liquid fertilizer with potassium dihydrogen phosphate can be used for prevention and control.

Method 2: For brown spot disease, spray potassium dihydrogen phosphate, difenoconazole, tebuconazole combined with potassium dihydrogen phosphate spray, two to three times at a time every seven days, pay attention to the concentration.

Method 3: Brown spot disease mainly harms leaves, and the middle and lower leaves are seriously damaged It is easy to develop under the conditions of high humidity or poor ventilation, the temperature is 25-27, and the temperature is saturated. Tebuconazole 4000-6000 times liquid spray 20% thiamium copper 83-166 grams of mu spray Kinder or Luna Sen, etc. + amino acid foliar fertilizer alternately for prevention and control.

Method 4: Brown spot disease is sprayed with 250 grams of 2000-2500 times of oxaconazole, 5000-6000 times of 75% fenoconazole, 4000-6000 times of 30% difenoconazole and 2000-2500 times of 10% flusilazole can be used alternately.

Search on the Internet, there are many products and methods.