Fungal diseases of tomatoes: signs of appearance and methods of prevention

At the mention of homemade tomatoes, colorful pictures flash through your head - homemade sauce; cans of canned tomatoes neatly arranged on pantry shelves; tomatoes in salads or just juicy fruits straight from the bush! And now you go out into the garden to once again inspect and water your plantings, and you see something strange on the bushes with tomatoes. The leaves are covered with grayish-brown spots; brown lesions are noticeable on the stems and petioles. What is it? Most likely, your tomatoes are infected with a fungus.

About fungal diseases of tomatoes

Alternaria - a disease caused by spores of a fungus called Alternaria solani. This pathogen can affect almost any ground part of tomatoes - stems, leaves, fruits. The disease does not always lead to the death of plants, but greatly weakens them and significantly reduces the yield. Favorable conditions for the development of fungi are wet weather and abundant dew. Spores of the pathogen can persist in the soil and even overwinter on infected plants that were not removed last year during the autumn harvest. As a rule, most pests and diseases affect the weakest plants first.

The signs of Alternaria are the appearance of spots on the leaves, which then turn yellow and fall off. The spots look small at first, but they grow in size over time. Lesions are also noticeable on plant stems. When the infection reaches the fruit, dark, round, depressed spots appear on them near the stalk, and they can be seen on both ripe and unripe tomatoes. Your plants will be able to survive this attack, but the quality and quantity of the fruit will be affected. Alternaria is a rather unpleasant disease, but it is as destructive to plants as late blight.

Late blight - a dangerous fungal disease caused by spores of the fungus Phytophthora infestans, which means “destroying plant”. This mushroom can really not only destroy the entire crop, but also infect other plants. Spores can be carried by the wind from one area to another. The infected plant should be dug up and destroyed (it cannot be used for compost!).

Late blight is manifested by bluish-gray spots, which turn brown over time, and the leaves themselves curl up, dry up and fall off. Leathery brown spots of indeterminate shape can also be found on fruits. Often the spots on the leaves and fruits are bordered by white mold. Obvious signs of late blight appear from mid-summer, when conditions are favorable for the rapid development of the fungus - cool and damp weather. A dangerous disease can destroy plants in just one week.

Methods for the prevention of fungal diseases of tomatoes

Growing the most disease-resistant tomato varieties:

• Stupais;
• The Iron Lady;
• Jasper (red cherry);
• Lemon drop (yellow cherry);
• Prudence purple;
• Red currant.

Even better, if you manage to find grafted tomatoes - they are distinguished by active growth and endurance.

Prevention of Alternaria:

1. Buy seeds and seedlings only from trusted sources, never use seedlings suggested by friends or neighbors.
2. When planting, keep sufficient distance between the plants for good air circulation.
3. Add a layer of mulch on top or use special red plastic for tomatoes that cover the soil. This will provide a barrier between foliage and soil in which fungal spores can reside.
4. Inspect the plants regularly, especially in wet weather or when the weather conditions change dramatically.
5. If you notice something even remotely resembling a fungal disease, immediately start regularly spraying the bushes with safe products - copper-containing organic fungicides and biofungicides. Both those and others are harmless to vegetables eaten. Alternate between these remedies after about a week (their effectiveness may decrease if used simultaneously). Be careful when using copper-containing preparations - spray them early in the morning so as not to harm the bees; the product can accumulate in the soil and lead to its toxicity, so in the place where you often use products with copper, tomatoes may not grow every year.
6. At the end of the summer season, clean your garden thoroughly and get rid of all plant residues.
7. During a disease outbreak, try to save healthy plants, even if you need to transplant them into containers to do so.

Prevention of late blight:

1. Do not leave any plants for the winter and remove any independently sprouted tomato and potato bushes. Potatoes can carry spores.
2. Use trellises and plant supports or a layer of mulch or shelter (see above) to keep foliage out of the soil.
3. Water the plantings at the root and avoid excess moisture. Watering is best done in the early morning so that the plants and topsoil have time to dry out before nightfall.
4. As a preventive measure, you can use biologically active preparations containing beneficial bacteria.
5. Hydrogen peroxide solution is another safe and effective means for sterilizing plants and protecting against late blight.

Keep in mind that all of the above means are only suitable for preventing the disease. If the plant is already infected, it must be destroyed (burned) without regret. Never compost diseased plants, as late blight is a contagious disease that can spread not only to your plants, but also to the plantings of your neighbors!

Although it is very difficult to combat late blight in tomatoes in a cool and humid climate, the use of preventive measures will still help reduce the likelihood of outbreaks of this dangerous fungal disease.