Diagnostics of tomato condition by leaves and methods of disease treatment

Diagnosing tomato condition based on leaf status

First and foremost, look at the leaves, as they are an indicator of the well-being of tomatoes.

If leaves are matte with a grayish hue or are too pale and small, this is a nitrogen deficiency. Apply top dressing using a weed infusion, urea, or any nitrate fertilizer (1 tablespoon per bucket, half a liter per root).

If a purple hue appears on the underside of the leaves or the leaves press against the stem and turn upward, this is a phosphorus deficiency. Add 1 tablespoon of superphosphate under each plant and incorporate it into the soil, avoiding contact of the fertilizer with the stem and leaves.

You will achieve a faster effect if you apply the superphosphate to the tomatoes during irrigation as an extract. To do this:

• Pour 1 liter of boiling water over 1 cup of fertilizer and let it stand overnight.
• Dilute this solution in 10 liters of water.
• Water the plants (half a liter per plant).

If a drying border appears on the leaf edges or they roll upward into a tube, this is a potassium deficiency. Apply any potassium fertilizer that does not contain chlorine, preferably potassium nitrate (1 tablespoon per bucket, half a liter per plant), or add half a cup of ash under each plant onto moist soil.

If the leaves curl downward like a little boat (chicken foot), do not pay attention; this is either a cultivar characteristic, or the central vein is growing faster than the leaf blade, causing it to curl.

If the leaves have acquired a marbled light- and dark-green coloration, this is a magnesium deficiency. Add half a cup of dolomite under the plant onto moist soil. For a quick effect, you can provide foliar top dressing by dissolving 1 teaspoon of magnesium nitrate or 1 teaspoon of Epsom salt in 10 liters of water.

If the leaves have acquired a mosaic yellow-green coloration, this is a deficiency of a certain micronutrient. Dilute 2 teaspoons of "Uniflor-micro" fertilizer in 10 liters of water and spray the plants in the evening if the weather is dry, or water them (half a liter of solution per plant) if the weather is humid.

However, such a leaf mosaic may also be caused by tobacco mosaic virus. In this case (if 5–7 days after top dressing with "Uniflor-micro" micronutrients did not help), the plant must be destroyed and burned.

Prevention and treatment of fungal diseases

If black spots appear first on the lower leaves and then on the others, which then begin to increase in size while a yellow spot forms around them, this is a formidable tomato disease: late blight, a fungus that lives in the soil, but only when there is a deficiency of copper in it.

Hence the disease prevention: before planting, water the soil with copper oxychloride ("Khom", "Oksikhom", "Polikhom") or copper sulfate, or use the "Profit" preparation:

Keep in mind that after spraying with preparations containing copper, the fruit must not be eaten for 3 weeks.

You can preventively spray tomatoes with an infusion of polypore fungus:

1. Crush 100 g of the fungus.
2. Pour boiling water over it, cover with a lid, and let it cool.
3. Strain and spray the tomatoes on the leaves immediately.
4. Repeat the spraying in 10 days.

Such preventive spraying is recommended to be done in late June – early July.

Control measures for tomato late blight

If late blight has just begun, you can spray the tomatoes with an iodine solution (a 10 ml vial of 5% iodine per 10 liters of water). Repeat the spraying in 3 days. By the way, the solution keeps for an unlimited time and can be used to spray other plants against all fungal and bacterial diseases. You can use the newest biological preparation "Zircon", which enhances the plants' own resistance to diseases.

In case of severe late blight infection:

• diseased leaves must be removed and burned;
• spray the fruit with a 1% calcium chloride solution (a 10% solution is sold in pharmacies in 200 ml vials). A vial should be dissolved in 2 liters of water. The peduncle should be sprayed especially carefully, as late blight penetrates the fruit through it.

After harvesting tomatoes that are heavily affected by late blight, the fruit should be immersed for 10 minutes in a hot (40 degrees) pink-colored solution of potassium permanganate.

☝Do not make the solution too dark – it will cause burns on the fruit skin.

Take the fruit out, wash with water, and wipe dry. After this, they can be placed in storage by wrapping each fruit in paper. Then the late blight will not spread from one fruit to another if, by chance, one fruit starts to spoil.

Sometimes gardeners insert a thin copper wire into the stem to avoid late blight. In my opinion, it is better to gradually saturate the plant with copper by spraying it 2–3 times during the growing season, starting from the transplants stage, with a weak solution of copper oxychloride (1 g per 1 l of water). In addition, regular preventive spraying of plants, as well as irrigation of the soil under the tomatoes with the "Phytosporin" preparation, is quite helpful, but it should be started from the end of June.

Tomatoes growing in open soil are, as a rule, not prone to fungal diseases, but if the fruits lie on the ground, their disease with late blight cannot be avoided.

☝There is one traditional method of fighting fungal diseases: dissolve a yeast cake in 10 l of water and irrigate the plants over the leaves. Would you like to try it?

Treatment of mold, rot, and wilting

Another formidable disease of the tomato is leaf mold. The disease manifests itself in the form of yellowish spots on the leaves that stain the hands; subsequently, the leaves dry out. The disease spreads very quickly and can destroy tomatoes in a greenhouse in just a week. The disease is provoked by excessively high (95%) humidity in greenhouses. At the very beginning of the disease, irrigation must be stopped, the soil should be sprinkled with chalk or ash, the greenhouses should be well ventilated, and the diseased leaves should be removed and burned.

Less common diseases include white and gray fruit rot, which manifest themselves in the appearance of rotten spots on the fruits, often near the stalk, which causes them to fall off. The best protective measure is good ventilation of greenhouses and spraying the fruits with "Phytosporin".

Wilting of the tomato is usually caused by stem rot. In this case, there is nothing left to do but dig up the plant and destroy it.

Blossom-end rot more often affects peppers, but sometimes occurs in tomatoes as well. It is not a disease, but a deficiency of potassium, calcium, and moisture. The plant begins to pump them into the growth point from the top part of the fruits. The fruit tissue dehydrates, turns pale, then dies off and rots. As soon as you notice light spots on the fruits, provide irrigation and top dressing with calcium and potassium nitrate (1 tablespoon of each per 10 l of water).

Pest control in greenhouses

There are not many tomato pests, but there is one quite dangerous one – the whitefly (a small white moth). The whitefly is a sucking pest, very prolific. It can be destroyed with chemical poisons "Top-star", "Confidor" or "Commandor", after spraying with which the fruits cannot be eaten for 20 days. They are usually used only after harvesting, if the pest attack is too severe.

There is a less effective (against whitefly), but environmentally safe biological agent "Fitoverm", after the application of which the tomatoes can be eaten after just 2 days. In greenhouses, you can use special adhesive trap plates for flying insects.

Typical failures in growing tomatoes

Problems that arise during crop care:

• No fertilization occurs – the reason is high humidity or high temperature in the greenhouse (spray in the morning hours with "Buton" or "Zavyaz" preparations and ensure good ventilation of the greenhouses).
• Fruit sets fall off – the reason is excessive top dressing with nitrogen or manure, or an infusion of weeds after transplanting to a permanent location. For this same reason, there is a delay in fruiting and excessive growth of the above-ground part.
• Tomatoes form fasciated (double) flowers – the reason is low temperatures during the formation of flower buds; deformed tomatoes fused from several fruits are formed from fasciated flowers, and their seeds should not be collected, as this deformity can be passed on to the offspring. That is why abnormally large buds of fasciated flowers should be removed while still in the bud stage.
• Early late blight disease – the reason is a lack of copper in the soil, high humidity, poor ventilation, and crowded planting. By the way, with my method of growing tomatoes in a greenhouse, the crowding of the planting is actually high. I have 9–10 tall tomato plants growing on every square meter.
• Slow growth of fruit sets – the reason is a prolonged cold spell, cloudy weather, or a sharp change in day and night temperatures. In this stressful situation, you should apply top dressing with calcium nitrate (3 tablespoons per 10 l of water, half a liter of solution under each bush) and spray with a solution of "Ekoberin", or "Novosil", or "Epin-extra".