How your tomato seedlings can get sick, and how this can end

Tomato seedlings do not get sick as often as adult plants in the greenhouse and garden. But any infection with bacteria and fungi at an early stage of seedling development leads to their death. Viral lesions are no less dangerous - they are characterized by a hidden course and appear only after the seedlings are planted in a permanent place.

Disease control is difficult due to the impossibility of using chemicals indoors. The situation is aggravated by the fact that many folk remedies are ineffective. Experienced gardeners advise focusing energy on preventative treatments.

In this article we will describe diseases of tomato seedlings of infectious and non-infectious nature, and talk about methods of control and prevention.

Main diseases of tomato seedlings

All diseases of tomato seedlings are classified into:

• fungal;
• viral;
• bacterial;
• non-infectious nature.

Modern varieties and hybrids have genetic immunity to viral diseases of nightshades. Infection with viruses and fungi occurs due to improper care, ignoring the rules for disinfecting soil and seeds, and a deficiency of minerals.

Fungal diseases

Tomato seedlings most often die as a result of infection by pathogenic fungi. The main cause of infection is poor quality soil.

Blackleg or root rot is a fungal disease whose pathogens live in the upper layer of the soil.Under favorable conditions, the fungus quickly spreads to plant tissue: without treatment, the seedlings completely die in just a couple of days. Seedlings after picking are most vulnerable to disease.

Blackleg

Signs of the disease:

• darkening of the root collar;
• drying of the affected part;
• constriction in the area of ​​the lower part of the stem;
• Root rotting.

If you pull the stem, the plant easily comes out of the ground. The root system completely rots.

Causes:

• contaminated soil;
• failure to comply with soil disinfection rules;
• excessive watering;
• dense sowing;
• lack of fresh air;
• temperature jumps.

The fight against the disease is hampered by the inability to use chemicals indoors, and there are no effective folk remedies.

At the first signs, the seedlings are removed by the roots, and the remaining seedlings are irrigated with a solution of potassium permanganate and watering is stopped for a week.

If after seven days no signs of infection are detected, the seedlings are watered with solutions of biological products:

• “Fitosporin” (10 g per 5 l, 100 ml per sprout);
• "Trichodermin" (100 ml per 10 liters of water);
• "Maxim" (2 ml per 1 liter of water);
• "Previkur" (10 ml per 7 liters of water).

Fusarium

Fusarium wilt – a disease caused by fungi of the genus Fusarium. The pathogen penetrates plant tissue through damaged roots during picking.

Signs:

• pink bloom on the stem and root collar;
• wilting of the lower leaves;
• yellow veins on the leaves.

The process develops rapidly, the greens do not have time to turn yellow, the stems fall, but hold tightly to the root.

Causes:

• sowing seeds into the soil without prior disinfection;
• increased soil moisture;
• high substrate temperature (+24…+30°C);
• excess nitrogen in the soil.

For treatment, use “Trichodermin” (100 ml per 10 liters of water) and a strong solution of potassium permanganate.

Late blight

A disease of nightshades caused by the fungus Phytophthora. The pathogen spreads with lightning speed in conditions of high humidity and completely destroys plant tissue.

Signs:

• brown spots on the tips of leaves;
• brown spots with a whitish coating on the back side;
• brown streaks on petioles.

At the initial stage of development, tomato seedlings tolerate the disease more easily and usually do not die. Insidiousness late blight lies in its amazing vitality. Even if the signs of the disease completely disappear, the seedlings remain carriers of the pathogen, and after transplantation into the soil, the pathogenic process unfolds with renewed vigor.

Causes:

• contaminated soil and seeds;
• excessive watering of seedlings;
• excess nitrogen in the soil;
• lack of fresh air.

When the first signs are detected, it is better to remove the seedlings by the roots and throw them away. If seedlings need to be preserved at any cost, they are treated with copper-containing preparations:

• “HOM” (20 g per 5 liters of water);
• "Abiga-Peak" (25 g per 5 liters of water).

Reference. Bordeaux mixture is ineffective in the fight against late blight of tomato seedlings.

Septoria or white leaf spot

Disease, caused by the fungus Sephtoria lycopersici. Seedlings become infected through the soil.

Signs:

• whitish spots with black dots (spores) on the lower leaves;
• darkening and bending of leaves;
• oval spots on stems.

Without treatment, the stems dry out completely and the leaves fall off.

Causes:

• excessive soil and air moisture;
• contaminated substrate;
• increased indoor air temperature.

If the disease is detected at an early stage of seedling development, it is better to pull out the sprouts and destroy them; they cannot be saved. Strengthened seedlings are sprayed with Bordeaux mixture.

To prepare a 0.75% solution you will need:

• 10 liters of water;
• 75 g of copper sulfate;
• 100 g quicklime.

Treatment is carried out twice with an interval of 10 days.

Viral diseases

The symptoms of viral diseases at the stage of growing tomato seedlings are smoothed. Often the signs are completely absent, and the disease fully manifests itself after being transferred to the ground.

Tomato mosaic

A dangerous viral disease, the causative agent of which is hidden in the seeds.. It is useless to fight the disease; you have to completely get rid of the seedlings. Light spots appear on the leaves, arranged in the form of a mosaic. Then they turn completely yellow, wrinkle and crumble.

To prevent infection:

• the seed is pickled in a strong solution of potassium permanganate;
• seedlings are watered with a 1% solution of potassium permanganate - twice a month;
• spray with a solution of urea in milk (per 1 liter of milk - 1 tsp of urea), once every 10 days.

Aspermia or seedlessness

A disease caused by the Cucumovirus virus. The virus is transmitted through infected plants under conditions of high temperature and humidity. The main vector in open and closed ground is aphid.

The disease does not appear at the seedling stage; the first signs can be noticed after planting in the ground. Characteristic symptoms of infection are excessive bushiness of the top, underdeveloped stepsons. The upper leaves become lighter and deformed. The fruits are partially or completely missing seeds.

To prevent the spread of the pathogen, small, sickly seedlings are discarded during picking, and strong ones are left. At the first symptoms of the disease after being transferred to the ground, seedlings are treated with fungicides “Aktara” and “Commander” to kill aphids.

Streak

A common disease of tomatoes caused by the tobacco mosaic virus. The reason is growing seedlings from seeds of an infected fruit.

Signs:

• stripes and streaks of brown-red color;
• fragility of stems;
• dark brown spots on leaves;
• new leaves grow curly and small.

Out of ignorance, the disease is easily confused with late blight. One disease differs from another in the nature of the spots: streak gives dry, brownish-brown color, and late blight produces weeping, gray-brown.

For treatment, use a solution of potassium chloride (40 g per 10 liters of water). But the safest thing to do is to remove the seedlings by the roots and burn them.

Bacterial diseases

This is the most common group of diseases of tomato seedlings. Treatment is complicated by the lack of effective antibacterial drugs, so the main fight is aimed at preventing infection.

Black bacterial spot

A disease caused by the gram-negative bacillus Xanthomonas vesicatoria. A favorable environment for the development of the disease is an air temperature of more than +25 °C. Bacteria die at +54 °C.

Signs:

• fatty, olive spots on leaves with a diameter of 1-2 mm;
• small black spots (without a white border) in the form of a rash on the stems, leaves, petioles;
• leaf dying.

Causes:

• increased air temperature;
• air humidity above 75%;
• moisture getting on the leaves when watering.

The following drugs are used to treat the disease:

• “Fitosporin M” (10 g per 5 l, 100 ml per sprout);
• “Fitolavin” (2 ml/1 l of water);
• “Gamair” (2 tablets/1 liter of water);
• “HOM” (20 g per 5 liters of water).

Solutions are used to spray leaves once every two weeks.

Bacterial mottling

Disease caused by the bacterium Pseudomonas syringae. Pathology does not cause any particular harm to seedlings when the process is controlled.

Signs are small brown spots with a yellow border on the lower leaves, yellowing and curling of the leaves.

The reasons are low temperature and high humidity.

Damaged leaves are removed and the seedlings are treated with HOM.

Non-communicable diseases

A group of non-infectious diseases is associated with a deficiency of mineral components: calcium, copper, phosphorus, potassium, nitrogen.

Diseases can be recognized by leaf shape and color. Feeding seedlings throughout the growing season will help solve the problem.

Signs of mineral deficiency:

• yellowing of the upper leaves indicates a lack of calcium;
• yellow and dry lower leaves - lack of copper and potassium;
• the upper leaves are curled - lack of potassium;
• yellowing of leaves and red veins on the back side - nitrogen deficiency;
• light yellow color of the entire seedling – lack of magnesium;
• yellowed and curled leaves – lack of iron;
• pale leaves with a blue tint – copper deficiency;
• A blue or purple tint to the leaves is a phosphorus deficiency.

Similar symptoms occur with insufficient watering and lack of sunlight.

And vice versa: as a result of sunburn, tomato leaves turn white, but the stems remain green.

To feed tomato seedlings at home use: “Kalbit S”, “Brexil Sa”, “Vuksal Calcium”, “Biohumus”, bird droppings, mullein, superphosphate, potassium sulfate, copper sulfate, magnesium nitrate, yeast, ash.

Prevention of seedling diseases

General rules for the prevention of viral, fungal and bacterial diseases:

• disinfection of soil and containers before sowing seeds;
• soaking seed collected by hand in potassium permanganate or Fitosporin;
• preventive treatment once a week with biological preparations “Baktofit”, “Trichodermin”;
• moderate watering;
• maintaining optimal levels of humidity and temperature;
• ventilation of seedlings;
• removal of infected seedlings with roots;
• thinning of seedlings;
• treatment of roots with biological preparations during picking and transfer to the ground.

Prevention of non-infectious diseases consists of timely application of organic and mineral substances and compliance with the rules for caring for young seedlings.

Conclusion

Tomato seedlings are susceptible to a variety of diseases. Pathologies are caused by: ignoring recommendations for disinfecting soil and seeds, excessive watering, too high or low indoor air temperature. Fungal and bacterial diseases are detected immediately after picking seedlings; viral diseases are asymptomatic.

It is prohibited to use chemicals to treat diseases at home. Methods for treating seedlings include treating the seedlings with biological products and preventing infection. It is during the period of “tender” age that it is easier to prevent the disease than to deal with the consequences.

Non-infectious diseases are associated with mineral deficiency and appear in the form of curled, dry, yellow, purple leaves. Ready-made liquid fertilizers with nitrogen, potassium, phosphorus, calcium and magnesium help normalize the balance of nutrients.