Phytophthora on tomatoes [how to treat, prevention, resistant varieties of tomatoes]

Late blight on tomatoes is the most harmful disease of tomatoes. How to treat plantings against late blight? What effective modern chemical and biological products should I choose? Do folk remedies help against late blight on tomatoes and which ones are used? Preventive measures to prevent the appearance of late blight on your site in the future. What varieties of tomatoes are resistant to late blight, so as not to repeat mistakes?

Late blight or late blight (pathogen Phytophthora infestans) is a fungal disease well known to every gardener.

Late blight is the most insidious disease of tomatoes, capable of causing significant damage or even destroying almost the entire tomato crop. Therefore, it is important to prevent the spread of late blight on tomatoes and pay attention to prevention.

But if signs of late blight on the leaves or even the fruits, it is necessary to urgently take measures to save the crop.

Fighting late blight on tomatoes

The earlier the disease is detected, the greater the chance of saving your tomatoes and avoiding the spread of the disease. If there are obvious signs of late blight, the plant cannot be cured . The main thing is to delay the spread of infection, otherwise you may lose the entire harvest. Diseased leaves must be removed immediately upon detection. This must be done extremely carefully, as fungal spores can get on healthy plants. If there are buds on infected bushes, they need to be cut off, since the ovaries become diseased faster than the fruits.

Treatment must begin with the immediate collection of all unripe fruits. Sort out whole ones that have not yet become infected with the disease and place them in hot (about 65°C) water for 2-3 minutes. Then the tomatoes must be thoroughly wiped, dried and left to ripen at room temperature. Otherwise, there is a risk of losing the entire harvest.

The next stage is treating the plants with a late blight remedy.

How to treat tomatoes against late blight in a greenhouse

Preparations used for late blight: Bordeaux mixture, Hom, Ordan, Oxychom, Quadris, Profit Gold, Revus. Repeat the treatment once every 7 days (the number of treatments is according to the instructions for the drug).

Biological products used : Alirin B, Gamair, Fitosporin M, Trichodermin.

Using a special tobacco stick . The bomb is burned in a greenhouse containing infected tomato bushes. Interesting video about tobacco shank.

Treatment of tomatoes against late blight in open ground

The same fungicides are used ( Bordeaux mixture, Hom, Ordan, Oksihom, Quadris, Profit Gold, Revu ), but they are used in a stronger solution concentration. All recommendations for the use of drugs for open or buried ground are indicated in their instructions.

Reviews

Each vegetable grower chooses for himself the best option for combating late blight .
Some of them leave useful information in reviews. Inna, Moscow : “In our damp, cool climate, late blight is a common problem.
I grow mainly cold-resistant varieties with immunity to fungi, but this does not always help. In my experience, it is useless to fight late blight once its symptoms have appeared on plants. I pay maximum attention to prevention. I plant tomatoes in the most sunny areas of the garden, using drip irrigation. After any precipitation or cold weather, I always spray the bushes with a solution of furatsilin or iodine.” Andrey, Belgorod : “I grow tomatoes only in open ground. Late blight usually affects them at the end of August. I make sure to follow the rules of care and spray the bushes with an ash solution and soap. If late blight appears during the ripening process, then I remove the unripe tomatoes, wash them with a weak solution of potassium permanganate, wipe them dry and leave them to dry in the sun. I cut off ripe fruits with spots and use them for preparing hot dishes.”

Preparations against late blight of tomatoes

Tomatoes can be treated against late blight using both biological products and chemicals . (fungicides). Biological products are somewhat weaker than chemical ones, but safer. Disease control chemicals can persist in fruit tissue for up to 30 days .

Recently, folk remedies are often used to treat tomatoes against late blight. Let's look at what and how to treat tomatoes with preparations.

Biological products against late blight

There are more modern and environmentally friendly methods of combating late blight and other fungal diseases - with the help of biological preparations. They contain living microorganisms that feed on fungal spores. And if chemical plant protection products suppress almost all the simplest soil fungi, including useful ones, then biological preparations do not allow pathogenic fungi to spread.

Among the biological products against late blight, the following are used:

Alirin-B is a biological preparation against plant diseases, containing the bacteria Bacillus subtilis. Consumption rate for late blight: 2 tablets per 10 liters of water when watering plants, and 2 tablets per 1 liter of water when spraying. Repeated treatment after 5-7 days, up to 3 treatments in total.
Gamair is a biological preparation against late blight, the consumption of the drug is 1 tablet per 5 liters of water when watering, and 2 tablets per 1 liter of water when spraying. Treatments are repeated every 7 days, three times.
Fitosporin-M is a biofungicide in the form of a dark brown paste, liquid or powder. In gardening, either powder or paste is used. (more details below)

Chemicals against late blight on tomatoes

Bordeaux mixture. A contact action product that has been tested for years. Perfectly protects tomatoes from fungus . In addition, the composition effectively helps in the fight against the most common diseases.
Oxychom (copper oxychloride + oxadixil) is a contact-systemic fungicide against late blight. Dilute 1 packet (4 grams) per 2 liters of water. Plants are sprayed as necessary up to three times with an interval of 10-14 days.
Ordan - (copper oxychloride + cymoxanil) - in the form of a wetting powder. Spray twice with an interval of 7-14 days, at the rate of 25 g per 5 liters of water.
Ridomil Gold (mancozeb + mefenoxam) is a combined fungicide against late blight, a very effective product, available for personal households in 10 g bags. You need to dilute 1 bag (10 g) in 2 liters of water. This is enough to process 40 square meters. m. planting tomatoes. Spray the first time when the tops of the bushes close in the beds, the second time after 10-14 days.
Quadris is a new systemic product with a wide spectrum of effects that can protect plants from many diseases. It belongs to a new class of drugs - strobilurins . The composition, as soon as it hits the foliage, suppresses painful pathogens. Its effect helps stop the spread and development of infections in the beds. The drug belongs to hazard class 2 , so it must be used carefully, following the instructions for use.
Acrobat. Today it is used against late blight more and more often. The product is especially popular in the southern regions of the country. Fungal bacteria have not yet been able to acquire resistance to this product.

Effective remedies for late blight on tomatoes

If the plants are severely damaged, spraying the tomatoes with a solution of potassium chloride can help. This method has long been successfully used by the famous gardener Kizima Galina Aleksandrovna .

To prepare the solution, you need to dilute 200 ml (1 bottle) of a 10% preparation in 2 liters of water. Both the fruit and the stalk should be sprayed

tobacco block is also effective . This method is only suitable for greenhouses (see video above) .

Signs of illness

Late blight disease looks like rot. This is explained by the fact that the infection develops under the influence of moisture.

Tomato disease is determined by the following characteristics:

the presence of a whitish coating;
dark brown spots on leaves, fruits, stems;
withering and drying of the entire vegetable crop;
unpleasant smell of vegetables;
unsuitable for consumption.

Read on to learn how the disease develops and spreads.

Folk remedies for late blight on tomatoes

Iodine for late blight on tomatoes

If signs of the disease appear, it is necessary to immediately spray the plantings with a solution of 5% iodine. For a bucket of water (10 l), 1 jar (10 ml) is enough. After a few days, the treatment must be repeated.

Milk and iodine for late blight

Recipe 1: For 10 liters of water - 1 liter of low-fat milk + 20 drops of iodine. Treatment of plants with this composition can be carried out once every 5-7 days.

Recipe 2: Pour 1 liter of skim milk into 10 liters of water and add 15 drops of iodine. The resulting solution is sprayed on the plants every 2 weeks. This iodine-milk preparation not only kills germs, but also accelerates the growth of green pets.

Late blight serum

The whey from sour milk is diluted with water in a 1:1 ratio and from the beginning of July the plants are sprayed every 2-3 days.

Boric acid from late blight

To prevent disease, seedlings are sprayed with 0.5% boric acid immediately after planting. The treatment is repeated every fourteen days with a one percent solution until the tomatoes begin to ripen.

Trichopolum from late blight of tomatoes

This drug (and its analogue, Metronidazole) can be bought at the pharmacy. 1 tablet of Trichopolum is dissolved in 1 liter of water and the tops are sprayed with this liquid once every 2 weeks. The drug is quite effective against the causative agent of late blight. But gardeners should be aware that the use of medicines in professional agriculture is prohibited. And there are good reasons for this.

Soda for late blight

Using a soda-soap solution against late blight:

For 1 l. warm water, add 1 tbsp. vegetable oil, 1 glass of liquid cosmetic or laundry soap. Stir, add 2 tbsp. baking soda.
Treat the soil around the plant and the tomatoes themselves once a week until late blight disappears.
You can enhance the effect of the solution by adding 0.5 matchbox of copper sulfate to the mixture. Seedlings can be sprayed with this solution once a week.

Copper wire against late blight of tomatoes

The most common way to combat tomato late blight is by spraying with fungicides that contain copper (Bordeaux mixture, Abiga-Peak, HOM - copper oxychloride, and others).

Copper is a trace element that, among others, is necessary for every plant. As part of oxidative enzymes, it enhances metabolism, increases chlorophyll content, and improves immunity. But the most important quality is that copper cannot be tolerated by fungi, which include late blight - late blight.

Recently, many people have been recommending the use of copper wire. Opinions are contradictory, but how does this affect tomatoes? The plant is injured and the trunk is pierced at the very bottom of the stem. In fact, the tomato body mobilizes in order to somehow overcome the problem and successfully bear fruit, and begins to work “for seeds” - this is such a program for all plants, if wounded, immediately switch to abundant fruiting (that’s why the advice is so common - an apple tree does not bear fruit, kill nail in it). But whether copper is involved as an element for feeding the bush is a controversial issue.

The technology for performing this operation is clearly visible in this video:

Basic methods of combating late blight of tomatoes

The main methods are to prevent its appearance on your site. What needs to be done to avoid the danger of diseases in tomatoes in the future and have a good harvest without unnecessary worries.

The season will end soon, which means it's time to think about next year's tomato harvest. Therefore, you need to know exactly and carry out measures to prevent late blight of tomatoes on your site. And even if your tomatoes were not affected by late blight this year, the insidious fungus can come either from seedlings or from other crops. In any case, we advise you to study preventive measures.

Choosing a location, proper care and the best neighbors

Maintain crop rotation - grow tomatoes for no more than 4 years in one place.
Do not plant next to or after potatoes, eggplants and peppers.
The best predecessors are cucumbers, onions, carrots, beets, turnips or cauliflower;
Grow disease-resistant and early varieties of tomatoes.
Potatoes must be treated against late blight. Since from it late blight spreads throughout the entire area.
Ventilate the greenhouse regularly to avoid condensation.
Fungal diseases develop well in high humidity and dense plantings.
Water at the roots so that water does not get on the stems and leaves.
Mulch the soil, do not allow the soil to become waterlogged.
Regularly remove shoots and lower leaves.
When pinching, treat the instrument with a solution of potassium permanganate for disinfection.
If the disease spreads, burn the infected tops and disinfect the greenhouses.
Do not grow in low-lying areas, where the air and soil are more humid.
Do not apply nitrogen fertilizers in the second half of the growing season. Excess nitrogen promotes the development of late blight
You can plant onions, garlic, marigolds, calendula, and mustard next to the blowing plants.

Protecting tomatoes from late blight in the greenhouse

Temperature changes in the greenhouse create favorable conditions for the development of late blight. Most often this happens at the end of summer. Falling dew increases the chances of late blight several times. Therefore, during the daytime, the greenhouse must be ventilated periodically.

Plants need to be watered in the first half of the day so that the moisture is absorbed into the soil or evaporates during the day. If the weather is damp and cloudy, it is better not to water the tomatoes at all.

Symptoms of late blight

Let's figure out what harm late blight causes and why tomatoes rot.

Phytophthora is a fungal , and if this fungus gets on a plant, that’s it, it’s infected, and as soon as favorable conditions for its reproduction are created (and this is humidity at a low temperature), the disease will progress until it infects the entire plant.

Tomatoes and potatoes suffer greatly from late blight, but cases of late blight infection in garden strawberries are not uncommon.

What does late blight look like ? The foliage and fruits of tomatoes are covered with brown spots without clear boundaries. The disease most often affects unripe tomatoes, when they are still green or slightly brown.

The damage caused by late blight is obvious - the crop may be completely lost, or at least a large part of it.

Residents of the northern regions complain the most about tomatoes being affected by this disease, since the summer there is short and differences in night and day temperatures begin at the end of July, when the tomatoes are still green even in the greenhouse.

Tomato varieties resistant to late blight

In order to reduce the risk of disease, you need to plant early and super early varieties of tomatoes. These varieties will have time to bear fruit before the peak of the disease spread. Unfortunately, there are no tomato varieties that are 100% resistant to late blight.

Varieties more resistant to late blight:

tomato Tatyana, tomato Budenovka, tomato Shuttle, tomato Dubok, tomato De Barao, tomato Metelitsa