Tomato leaves are covered with cobwebs, and then they turn yellow and dry up, what s going on?

Spider web-like marks on tomato leaves with yellowing and dryness may be caused by spider mites. Spider mites belong to the arachnidae, tick mites, and leaf mites family, and are one of the common pests of greenhouse vegetables. They feed on the sap on the back of the leaves of vegetables as adults, juveniles and nymphs.

There are many small green spots in the affected leaves at the beginning, and then gradually turn into gray-white and yellow spots, which will cause the leaves to scorch, fall off, and even die in severe cases.

To prevent and control the damage of red spiders, greenhouse management can be strengthened, and indoor residues and fallen leaves can be removed in time after the greenhouse vegetables are harvested, and taken out of the outdoor for destruction. In addition, regular spraying of acaricides, such as phenylbutyltin, alkyne mite, thiobenone, etc., can effectively control the population density of red spider mites and avoid their damage.

Hello, according to your account, it may be that your tomato seedlings have happened with red spiders. You can choose to spray the tomato seedlings in the spray, which is a ratio of 1:30 mixed with water and sprayed. Hope it helps.

This web-like substance is called a spider mite.

Prevention and control methods: 1. Soak the citrus peel with water about 10 times for a day and night, and spray the plants after filtration to prevent and control aphids.

Spider mites, such as pouring soil can be prevented.

Nematodes in the soil.

2. 15 grams of laundry detergent, 15 ml of 20% caustic soda, kilograms of water, spray after mixing the three, check after a day or two, red spider.

The mortality rate of full-fledged and full-fledged mites is 94%-98%.

3. Take 50 grams of plant ash.

Add 2500 grams of water and stir thoroughly, soak for two days and nights to filter, add 3 grams of laundry detergent to adjust evenly and spray daily.

Once, for three consecutive days, and then sprayed for three days every other week, it can eliminate the second generation of pests, and can also control aphids, red spiders, and scale insects.

Wait. Stinging and sucking pests. Put it in the taxi to control maggots.

4. Use a plate of lit mosquito coils, put them in the pots of diseased plants, and then tie them tightly with plastic bags, and after about an hour of smoke, they will not be successful.

Both eggs and adults can be killed. It's a great way to save money and get quick results.

The body of the spider mite is the size of a pinpoint, deep red or purplish-red, and only small red dots are visible to the naked eye, under a magnifying glass.

Under the ability to see oranges.

Red, transparent, globular eggs. Its nymphs often congregate on the dorsal and bud of some flowers, sucking the juice with their stinging mouthparts.

Damage to plants. The initial symptoms of flowers are leaf loss of green, leaf edge upturning, so that wilting, falling off, resulting in early atrophy of flower buds, and in severe cases, plants. Death.

The first thing to observe is that its yellow leaves start from **, if it starts from the edge of the leaves, then there will be some spots on the stem of the plant that are white, which may cause diseases. Secondly, if the tomato is not pruned carefully, it will cause a lot of damage to the stem, which will also give the bacteria a chance to attack. Finally, it is also possible that the roots of the tomato have been damaged, causing the leaves to turn yellow and wilt.

Tomato leaves are covered with cobwebs, and then they turn yellow and dry up, what's going on?

If you quietly dry the land, the leaves of the tomatoes will dry up, it may be a lack of water, and the plants will be in a state of extreme lack of water, and there will be dead leaves, so you should water them once every 2-3 days according to the situation. It is also possible to be infected with pests and diseases, and the insects will suck the nutrients in the leaves, which will also cause the leaves to dry up.

Carry out agricultural control, eradicate weeds at the edge of the field, and remove residual plants and leaves. It has a special effect on cinnabar leaf mite and two-spotted leaf mite is the bionic pesticide Nong Ke mite emulsifiable concentrate 2000 times, with excellent effect, long duration and no pesticide damage.

In addition, 20% emulsifiable concentrate 2000 times, 20% mite emulsifiable concentrate 2000 times, 40% amidophos emulsifiable concentrate 2500 times, 20% metformamidine emulsifiable concentrate 1000-1500 times, 10% Uranus emulsifiable concentrate 6000-8000 times;

10% imidacloprid wettable powder 1500 times, 8% afudin (BA-1) emulsifiable concentrate antibiotic insecticide 5000 times, 15% pyridafen (sweep mite, morning glory) emulsifiable concentrate 2500 times, 20% compound liuyangmycin emulsifiable concentrate 1000-1500 times, 2-3 times.

It is good to use avermectin, and dicofol is forbidden to use.

It's still edible I think it's okay to sterilize it.

You can't use your hands to catch the medicine.

The yellowing of the leaves is most likely due to a lack of nutrients and can be fertilized properly.

Principles of fertilization of tomatoes:

Tomato needs a large amount of fertilizer, and sufficient nutrition should be ensured in each period, but there are certain differences in the amount of fertilizer in each growth period, focusing on nitrogen fertilizer in the early stage, focusing on potassium fertilizer in the later stage, and the demand for phosphate fertilizer throughout the growth period. However, the demand for potassium fertilizer should be ensured throughout the growth period.

In tomato production, tomatoes should be fertilized with formulas. The production of 100 kg of tomatoes requires kilograms of nitrogen, phosphorus, and potassium. According to the yield of 5000 kg per mu, it should be applied in stages and in a timely manner, at this time, the amount of fertilizer is large, and the amount of fertilizer should be increased appropriately, each time per mu 29 kg of ammonium sulfate, 18 kg of superphosphate, 20 kg of potassium sulfate.

The main prevention and control methods are as follows:

1. In seriously ill areas, select excellent varieties that are relatively resistant to disease according to local conditions, and implement crop rotation with other vegetables.

2. Seed treatment: Before sowing, the seeds should be soaked in 52 warm water for 30 minutes, or soaked in 50 carbendazim wettable powder 300 times for 60 minutes.

3. Disease-free soil seedlings, old seedbeds with 50 carbendazim wettable powder, or 70 soil fungus wettable powder 45 75 kg of haectare mixed with fine soil 450 750 kg, sowing with medicated soil pad and cover seeds, or with 98 oxazine wettable powder 2000 times liquid spraying seedbed.

4. For drug prevention and control in the early stage of the disease, you can use 2000 times of 98 oxazine wettable powder, or 1000 times of 45 Tek multi-suspension agent, or 1500 times of 10 double-effect Lingshui solution, or 50 500 times of compound thiophanate-based wettable powder, or 2 200 times of 120 aqueous anti-bacterial powder, or 50 500 times of carbendazim wettable powder 500 times of liquid to water the roots, and water kilograms of liquid per plant, according to the disease prevention and treatment 1 3 times.

It may be Verticillium wilt. It's actually quite simple to know what to do. Find a friend who lives in the countryside and ask for it.

The main diseases of tomatoes are early blight, late blight, blight, gray mold, bacterial wilt, canker, leaf mold, brown spot, etc. With the development of solar greenhouses and the immobilized cultivation of plastic greenhouses, the soil-borne diseases and airborne diseases of tomatoes have a development trend. The most serious disease in many areas of open-field tomatoes is the virus disease.

Rainy years late blight, cotton blight, gray mold and other epidemics. There are many kinds of tomato diseases, and several diseases often occur at the same time in the same field, so comprehensive control is required.

Replace the seedling bed with new soil, or treat the bed soil with Lvheng No. 8 soil disinfectant drug (see vegetable seedling disease prevention and control for disinfection methods), or take the ground ** seedling and plastic bowl to raise seedlings to reduce root damage and shorten the seedling period (virus disease, wilt, canker, bacterial wilt).

Disease-free plants are harvested, or the seeds are blanched and soaked or mixed with agents such as Lvheng No. 1.

Implement crop rotation for non-solanaceae crops for more than 3 years.

In early spring, protected tomatoes raise ground temperature and temperature, and after flowering and fruiting, they increase ventilation, reduce humidity, and reduce dew condensation (gray mold, late blight, blight, canker, leaf mold).

Autumn tomato seedlings are raised in protected areas protected from rain, insects, shade (viral diseases, late blight, viral diseases, etc.).

Tomatoes in autumn greenhouses increase the air volume to reduce temperature and humidity (leaf mold, early blight, blight).

The focus of pesticide prevention and control is in the early stage of prevention and onset, and 8001000 times liquid spray can be used for gray mold and leaf mold and leaf mold. For stem, leaf and fruit diseases such as late blight, it can be sprayed with 8001000 times of water with Lvheng No. 2, which can treat a variety of diseases at the same time. against bacterial wilt, soft rot.

Virus diseases can be used Lvheng No. 6 (sterilization king) 10001500 times more happy spring, it is best to use 8 grams of Nuoer Poison Gram with 30 catties of water plus Green Wind 95' (nucleotides) 30 catties of water spray prevention and control effect is better.