Why light spots appear on tomato leaves: determine the cause and save our harvest

In addition to providing favorable conditions for growing tomatoes, you should learn to recognize possible plant diseases. The most common sign that something is wrong with your tomatoes is all sorts of stains on the leaves. What should be done in this case and how to deal with other diseases of tomatoes, you will learn from our article.

Determining the cause

How to understand that a plant is affected by some kind of disease? Quite simply: it begins to become covered with white and yellow spots.

If you recently moved a tomato to another location or watered too much, symptoms of infection may appear... The plant takes on an unhealthy appearance: spotting appears on the leaves, the stems wither and dry out, the fruits darken. Spots can form at the edges or in the middle, resemble a mosaic pattern, or appear on the top and bottom of the leaf.

If you notice any of these signs, the disease may have begun to develop.

Dry spotting, or alternaria

This disease is caused by fungi of the genus Alternaria. The disease affects many plants, so you should know how to deal with it.

Important! Alternaria is dangerous because its spores are quickly carried by the wind, raindrops and insects to healthy plants. The disease can destroy about 50% of the harvest of vegetables and fruits during the season.

In tomatoes, this disease is often called dry (or zonal) spotting. The disease is dangerous for all plants of the Solanaceae family and appears immediately after planting seedlings.

The entire upper part of the plant is affected: leaves, stems and fruits. The main sign that a tomato is infected with Alternaria is the appearance of clear, dry, gray-brown, rounded spots. Damaged leaves quickly turn yellow and fall off, the fruits die off.

To protect the plant from disease, it is recommended to treat its leaves and stems with Trichodermin in April and May. Do this when symptoms are already visible.

Spraying with “Quadris” (0.04-0.06%) is also effective when new symptoms appear. To protect the fruits from Alternaria, spray tomatoes with a 0.4-0.5% solution of Acrobat MC or Ordan (2.5-3 kg / ha). If you plant a plant in open ground, then use "Sectin Phenomenon" (1-1.25 kg / ha), "Ridomil Gold MC" (2.5 kg / ha), "Acrobat MC" (2 kg / ha), Metaxil (2.5 kg / ha), Poliram (2.5-3 kg / ha), Ordan (2.5-3 kg / ha), Cumulus (2-3 kg / ha) ).

In the photo you can see the consequences of the defeat of Alternaria.

Burns from ultraviolet radiation and mineral fertilizers

In summer, when it is particularly hot outside, tomatoes can get sunburn. Then white spots appear on the fruits and leaves of plants. Tomatoes stop growing, become hard, disproportionate and tasteless.

To protect plants from burns, try to cover them in the shade in hot weather - for this, use any material that prevents direct sunlight.

You can also burn tomatoes and mineral fertilizers. It is not recommended to buy preparations with a high nitrogen content. If you notice burns, use only half of the solution.

Cladosporium

Olive brown spot, or cladosporium, is a fungal disease that occurs primarily in greenhouses. First, the lower leaves are affected, then round yellow spots appear on the surface, which subsequently become one large spot.

A plaque forms on the lower part of the leaf - this is the appearance of fungal spores. As a result, the leaves begin to ache, curl, and then die. Usually, the disease manifests itself at the beginning of flowering or when fruits begin to set. It is believed that the earlier the disease manifests itself, the more dangerous it is. A favorable environment for the growth of the fungus is high humidity, long daylight hours and low illumination.

More often, only the stems and leaves of the plant are exposed to the disease, the fruits are rarely infected. If this does happen, the tomatoes acquire a dark brown color and become soft, and subsequently dry out.

The reasons why the disease may appear:

• watering with cold water;
• a sharp change in temperature;
• constant dampness.

Remove any spoiled leaves before medicating plants.

To cure the plant, medications containing copper must be used: for example, "Bordeaux mixture"," Barrier "," Barrier ".

White bloom on tomato leaves - powdery mildew

Powdery mildew (ash, linen) is a fungal disease, the signs of which can be seen in the upper part of the leaves: a grayish-whitish bloom that forms on seedlings and already adult plants. The mycelium of the fungus multiplies when the spores mature and liquid begins to appear on the leaf blades.

The disease affects young shoots and fruits. Symptoms first appear at the bottom of the plant, and then along the entire length. When the fetus is affected, crackling and rotting are considered a sign of infection, since infection gets into the gap.

The flowers begin to turn black and brown spots appear on the tomatoes. Infected fruits are hard at first and then soft.

If tomatoes are infected with powdery mildew, you can lose half of the crop, so you need to respond to symptoms in a timely manner and treat the infection. To combat, you can use chemicals - fungicides or folk remedies, which do not differ in effectiveness from chemical ones.

Soda-soap solution

To prepare 5 liters of the product, you will need the same amount of hot water, 25 g of soda and 5 g of soap. Treat not only the affected plants with the solution, but also the soil. Before this, the solution is cooled. To combat powdery mildew, it is necessary to repeatedly process the plants at intervals of 2-3 days.

Potassium permanganate solution

This remedy is known for its antibacterial and antifungal properties. To get rid of powdery mildew on tomatoes, you must use a solution prepared according to this recipe: add 2.5 g of permanganate to 10 liters of water and mix. Use every five days.

Also, tomatoes may have a disease such as septoria. Its main symptom is leaf damage. They turn dark and absorb moisture.

When the stem is infected, the spots become oval rather than round. In the last stage, the leaves dry out. As a result, the bush dies.

When a plant is infected with an infection, it is necessary to immediately begin to fight it. Use chemicals for treatment. Choose the fungicides "Revus" and "Thanos". Dilute them according to the instructions: 0.5 l of "Revus" per 1 ha, about 600 g of "Thanos" per 1 ha.

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Leaf mold, or brown spot

Leaf mildew is most common on plants growing in greenhouses.

This disease manifests itself mainly on the leaves and does not pose a danger to other parts of the plant. The disease goes from bottom to top: olive bloom begins to be seen in the lower half, and yellow spots appear in the upper part. They damage the surface of the leaves through and through. Then the spots turn brown and dark brown. After the disease rises upward, the dried leaves begin to fall off. Favorable temperature - 20-25 ° С, if the air humidity is at least 90%.

Control measures:

1. The disease can be stopped by immediately removing the infected leaves.
2. Quite good results are obtained by treatment with copper oxychloride (0.4%) once every 10 days. Before harvesting, you should stop processing for a month.
3. In greenhouses, air humidity should not exceed 60%. Avoid sudden temperature fluctuations.

Phomosis, or phoma rot

The disease affects the entire upper part of the plant. Small dark brown spots appear on the leaves, on which concentric rings can be seen.

Dark brown infested areas with concentric circles appear on the stems. Green and ripe fruits also get sick.

The disease remains in the ground, in plant debris, as well as on closely related plants. The infection spreads easily through raindrops and even workers' clothing. Low concentrations of nitrogen and phosphorus in the earth also contribute to an increase in the spread of the disease in plants.

Spraying with fungicides every day, improving sanitation and removing weeds similar to nightshades reduce the severity of the infection. Avoid damaging the plant when dry picking to reduce the spread of infection.

Lack of nutrients

Fungus and infection may not always be to blame for the painful appearance of tomatoes. In many cases, light spots on tomato leaves, their dryness and low plant growth can be associated with a lack of nutrients.

You need to find out what exactly is missing Nutrient deficiency can be determined by looking at the plant.

Potassium deficiency - with a lack of potassium, young leaves curl up, and old ones turn yellow and gradually dry out. It is necessary to treat the tomato with regular watering (at least 0.5 liters of solution should be used per plant, which is prepared from 5 liters of water and 1 tsp of potassium nitrate) and spraying with solutions containing potassium (2 liters of water and 1 tbsp. potassium chloride).

Nitrogen deficiency - the leaves of the plant first dry out at the edges, and then turn yellow and fall off. The bush grows, the leaves look lethargic and pale, and the stem becomes unstable and soft.

To replenish vitamins, make a nitrogen-containing top dressing. Water each bush with a solution of 5 liters of water and 1 tsp. urea.

Zinc deficiency can be identified by brownish spots on the leaves, curling upward, as well as small yellow spots. Tomato development is slowing down.

In this case, fertilize the plant with a solution containing zinc. You will need 5 liters of water and 2-3 g of zinc sulfate.

Molybdenum deficiency - the color of the foliage brightens and turns yellow. The edges begin to curl. It is necessary to feed the plant with 5 liters of water per 1 g of ammonium molybdate (0.02% solution).

Phosphorus deficiency - at first, the whole plant takes on a dark green hue, and then completely turns purple. In this case, the leaves begin to curl inward or rise strongly upward.

Fertilizer with phosphorus is prepared from 2 liters of boiling water and 2 glasses of superphosphate, then left overnight. Before watering, add 5 liters of water for every 0.5 l of solution.

Anthracnose

The infection is caused by several Colletotrichum pathogens. Some infect fruits, others - vegetative organs.

The anthracnose of tomato leaves already affects adult plants. The upper leaves wither first. Small black sclerotia appear on the infected sites.

The places where the spores are located are stretched along the stem or are located in groups of brown color: conidia measuring 15.2-22 × 3-5 μm, cylindrical or clavate with small rounded ends.

With anthracnose tomato fruits, soft or depressed spots are visible on the plant, which do not differ from the color of the fruit.

Tomato varieties resistant to anthracnose are LSL hybrids F1 Life, Shelf, Longf. To combat it, it is effective to soak seeds in a solution of one of the drugs: "Agat-25" (consumption 7 g / kg), "Immunocytophyte" (consumption 2 ml / kg).It is better to treat the plants with the Novosil preparation, and the seedlings at the stage of 2-3 leaves with the Agat-25 solution (consumption 14 g / ha).

Mosaic virus

Mosaic is a viral disease. The infection is very difficult to treat. All you can do is take preventive measures. The seeds should be processed before planting. It is useless to process infected plants.

The leaves of the infected plants become variegated and have a mosaic color: alternating dark and light green places. On the tomatoes themselves, yellow spot sometimes appears. If your tomatoes are infected with this disease, you need to remove them.

Tomatoes for open ground are sick with mosaics. The main source of infection is diseased seeds. For prevention, they must be etched before planting.

Reasons for tomatoes in a greenhouse

Preventing tomato infections in the greenhouse is essential before you plant them. Purchase a peat earthen mixture in stores. You can find special peat pots - seedlings are grown in them, and then planted in a greenhouse.

Many summer residents do not use pots, but collect land in parks and under trees. And then they add various additives to it, which makes the plant susceptible to infections.

Also, in addition to poorly prepared soil, there are a number of reasons why tomatoes are subject to infections: improper watering and a sharp change in moisture in the soil, untimely feeding, lack of nutrients and other trace elements, various diseases of fruits and stems.

In the open field

There are many reasons for tomato infection and fruit rot. Among them may be poor care, unfavorable environment, climate and others.

In addition to infectious diseases - top rot, late blight, fusarium and others - the reasons can be:

• lack of moisture;
• lack of magnesium and boron in the soil.

Important! Since the rot spreads instantly, you should carefully examine the bushes so that at the first signs you can begin to fight the disease.

How to save a plant

Every gardener should know that it is easier to stop an infection than to cure it. You can protect the plant by adhering to the following recommendations:

1. Look for fungus-resistant tomato varieties.
2. Process seeds before planting with 1% solution potassium permanganate or copper sulfate.
3. See nearby crops, especially potatoes.
4. Make live legume hedges near tomatoes to prevent fungal spores from spreading.

You also need:

• ventilate the greenhouse daily;
• moderately moisten the soil;
• plant tomatoes rarely;
• remove the surface of last year's humus.

Preventive measures

To prevent plants from becoming infected with diseases, they need to be grown according to the following rules:

1. First you need to choose the right variety. For greenhouses, you can take indeterminate varieties. In the fall, take the Uralsky multifruit variety. In the spring, choose the Leningrad early maturing.
2. If the yield of your varieties depends on the weather, plant several hybrids.
3. Take soil similar to greenhouse soil.
4. Water regularly, but in moderation.
5. Tomatoes love light.
6. Feed the plants periodically.
7. Tomatoes often infect fungal diseases, so several treatments should be carried out.

There are many infections that affect tomatoes. Diseases of tomatoes are successfully treated, but it is best to carry out prevention before planting.

Tips & Tricks

Here are some more helpful tips:

1. Plant tomatoes away from potatoes.
2. Grow tomatoes in greenhouses to limit infection.
3. Water the plants in the morning.
4. Avoid breaking or cutting the plants.
5. Remove all plant debris and dig the earth to a depth of 20 cm.
6. Observe crop rotation. Do not plant a tomato in the same place.

Conclusion

Now you know everything about the most common diseases and infections of tomatoes. Always select plant varieties that suit your climate and growing environment, and treat seeds and soil for good disease prevention. Try to keep your plants regularly watering. Take care of your tomatoes so that they will delight you with a rich and tasty harvest.