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Phytophthora is a fungus that can infect potatoes, peppers, eggplants and, of course, tomatoes, causing a disease such as late blight. Phytophthora spores can travel through the air with a wind stream or be contained in soil... In the "dormant" state, they fall on the leaves of plants and rest there until the onset of favorable conditions, after which they actively reproduce, causing harm to tomatoes.
More often you can find phytophthora on tomatoes outdoors in autumn, during prolonged cold snaps or after heavy rains. Fungi develop very quickly; tomato infection occurs within a few hours. That is why you need to use and know the preventive measures to combat the disease. The appearance of external signs of late blight infection on the leaves and trunks of tomatoes indicates an active stage of the reproduction of fungi. At this stage, various chemicals and improvised means can be used to save tomatoes.
Reasons for infection
Strong, healthy tomatoes in conditions with optimal temperature and humidity, regular, moderately abundant watering have sufficient immunity to resist late blight. And the fungi themselves cannot multiply in such conditions. Their active division and distribution occurs in an environment with high humidity and relatively low temperatures. Such conditions are typical for the autumn period, but they can overtake the gardener in the summer.
The following circumstances can provoke the division of phytophthora fungi:
- weather conditions with prolonged rains and cold snaps;
- frequent and sudden changes in temperature;
- lack of micronutrients in the soil;
- frequent, abundant watering;
- high concentration of nitrogen in the soil;
- growing tomatoes on wetlands;
- growing tomatoes in close proximity to other nightshade crops;
- dense planting of tomatoes without observing the recommended distances;
- growing tomatoes on soils of neutral acidity or a high concentration of lime in the soil.
Of course growing tomatoes in the open field, the gardener cannot influence the weather conditions in any way, but provide some protection from phytophthora for tomatoes, it is still possible by choosing sunny, windless areas of land for cultivation, where groundwater is located far from the surface. Distances between bushes when planting seedlings, they must be sufficient in order to ensure normal air circulation. Thickened plantings contribute to the rapid spread of fungal disease through the contact of tomato leaves and fruits. Particular attention should be paid to the choice of "neighbors" for tomatoes: you can not plant peppers, potatoes or eggplants close to tomatoes, it is better if it is, for example, garlic. In addition to the above growing conditions, there are other preventive methods for protecting tomatoes from late blight.
Prevention of late blight
Some tomato seed growers offer varieties that late blight resistanthowever, do not rely on such a "trick". There are no varieties with absolute protection against late blight.When purchasing seeds, you need to take care of the protection of tomatoes and the future harvest on your own at the stage of sowing seeds for seedlings:
- it is possible to destroy phytophthora spores from the surface of grains by soaking them in a special antifungal solution, for example, a solution of the drug "Phytodoctor" or "Fitosporin";
- phytophthora spores can also be contained in the soil for growing seedlings, therefore, before sowing seeds, it must be disinfected with boiling water. Heating in an oven or over an open fire is also effective;
- containers reused for growing seedlings must be treated with a solution of copper sulfate.
Subject to such simple growing rules, tomato seedlings are reliably protected from illness, however, when planted in open ground, the likelihood of infection with phytophthora fungi increases, which means that you need to resort to additional preventive measures to protect tomatoes.
Outdoor protection methods
Before planting tomatoes in the soil, the holes should be spilled with a solution of boiling water with the addition of potassium permanganate. Prevention of phytophthora on tomatoes in open ground can consist in treating the bushes with special biological products or folk remedies. Among biological products, the most effective are "Zircon" and "Fitosporin". These biological products should be diluted with water in accordance with the instructions, for example, for prophylactic spraying of tomatoes, add 2-3 tablespoons of "Fitosporin" to a bucket of water. This volume should be sufficient for processing tomatoes per 100m2.
Experienced gardeners often resort to folk methods of protecting tomatoes from phytophthora:
- Spraying with saline... You can prepare it by adding 1 cup of table salt to a bucket of water. After mixing, the tomatoes are sprayed with a solution, as a result of which the salt covers the leaves of the tomatoes with a dense film, preventing phytophthora spores from penetrating onto their surface.
- Spraying with ash infusion... Ash is not only a trace element fertilizer for tomatoes, but also an effective remedy against late blight. An ash solution can be prepared by adding 5 liters of this substance to a bucket of water. After mixing, the product is infused for 3 days, then 40-50 g of grated laundry soap is added to it. Ash, like saline, protects tomatoes by covering plant leaves with a film.
- Processing with fermented kefir or milk whey... These products are diluted with water in a ratio of 1: 9 and used to spray tomatoes.
In addition to the above methods for open ground, there are other ways to protect tomatoes based on the use of garlic, copper wire, iodine. An example of the use of folk remedies for late blight on tomatoes can be seen in the video:
However, it should be understood that such remedies can protect tomatoes from late blight, but not cure an already damaged plant. Therefore, they need to be used regularly for prophylaxis once every 10 days.
Tomato care rules
It is possible to reduce the risks of tomato infection with late blight if you follow certain rules for growing and caring for plants:
- You cannot grow tomatoes for two seasons in a row in the same place. In the place where nightshade crops used to grow, tomatoes can be grown only after 2-3 years. It is better to plant tomatoes in places where cauliflower, beets, carrots, onions, cucumbers used to grow.
- It is necessary to water the tomatoes early in the morning or after sunset exclusively at the root, since the accumulation of water in the axils of the plant provokes the development of phytophthora.
- On days with high humidity, it is recommended to refrain from watering, after only loosening the soil.It is worth noting that mulching, which allows you to retain moisture in the soil, is also considered a preventive measure in the fight against late blight.
- Healthy tomatoes have a certain immunity to late blight, so you need to regularly monitor their balanced diet, fertilize with phosphorus and potassium. The use of fresh manure and other fertilizers with a high nitrogen content for tomatoes is undesirable.
- Correctly forming tomato bushes, carrying out pinching, you can avoid thickened plantings and improve air circulation between the fruits and leaves of tomatoes.
Thus, observing the simple rules of caring for tomatoes and periodically carrying out their preventive treatment with biological products or folk remedies, you can reliably protect plants and successfully fight late blight even in favorable weather conditions for its development.
Signs of late blight
Many gardeners know the signs of late blight, however, unfortunately, they are the visible result of the already vigorous activity of fungi. In the early stages of infection, it is almost impossible to detect signs of late blight on tomatoes.
Symptoms of late blight appear a few days after infection. So, you can understand that tomatoes are infected by the following signs:
- Small spots appear on the inside of the leaf. Over time, they appear through the entire thickness of the leaf plate and acquire a dark, brown hue. As the phytophthora develops, the leaves dry out and fall off;
- Dark, and then black spots appear on the main trunk, tomato shoots. The lesions begin to dry out;
- Tomato ovaries turn black and fall off;
- Dark spots appear on the fruits, which subsequently turn into weeping rotten spots.
An attentive owner should regularly inspect the tomato plantings in order to detect and eliminate the problem in the early stages. In this case, it is worth paying attention to the factors provoking the disease: cold rains, sudden changes in weather conditions, and others. It is after such changes that one should expect the development of late blight, which means that it will be useful to treat the bushes with preventive remedies.
Treatment of tomatoes from late blight
If preventive measures to protect tomatoes from late blight were not taken or did not give the expected result and signs of the disease appeared on the leaves and trunks of the plant, then it is necessary to start treating the plants as soon as possible. For this, you can use special chemicals or some improvised substances.
Chemicals
There are various chemically drugs for late blight with high efficiency. Among them we should highlight Infinito, Metalaxil, Ecopin, Ditan M45 and some others. These substances are diluted in water in accordance with the instructions and used to spray tomatoes.
It is worth noting that all these substances are hazardous to human health, which is why it is preferable to use them before the fruit ripens. If chemicals were used during the ripening of vegetables, then the fruits should be eaten no earlier than after 3 weeks. During this time, the drugs cease to be active.
Improvised means of protection
In the fight against late blight, especially during the ripening of fruits, it is recommended to use folk, but effective methods of treating tomatoes:
- Antifungal and antiviral medicines, such as "Metronidazole" and "Trichopol" have long been used to combat late blight. Tablets are easy to find in any pharmacy, their cost is affordable. A solution is prepared from these antibiotics by dissolving 20 tablets in 10 liters of water.
- Copper sulfate can be used as a preventive remedy and for the treatment of tomatoes from late blight. It is used in the form of an aqueous solution by adding 2 tablespoons of the substance to a bucket of water. Such a remedy is effective, but it cannot be used often.
- Boric acid based you can prepare a remedy for the treatment of tomatoes from late blight. The substance is diluted in water in a ratio of 1 teaspoon to a bucket of water.
- Spraying on infected tomatoes 1% potassium chloride solution can defeat the disease. You can find the substance at the pharmacy.
The above methods of treating tomatoes are quite effective. However, it is necessary to use chemicals with extreme caution, the fruits after such treatment should be "kept" on the bush for at least 3 weeks and washed thoroughly before use. The means at hand do not pose a danger to humans, but in order to achieve high efficiency, they must be used several times with an interval of 7-10 days.
Dealing with damaged tomatoes
When the treatment of late blight-infected tomatoes is carried out, care must be taken to preserve the still unripe tomatoes and the already ripening crop:
- Remove and burn affected tomato leaves;
- Ripe, but blackened tomatoes will most likely have to be thrown away or the damaged parts of the fruit cut off and use "clean" tomatoes for canning;
- Unripe, but late blight-damaged tomatoes should be removed from the bush and heated in water with a temperature of 600C. To do this, pour the heated liquid into a basin or bucket and lower the tomatoes into it. As it cools, the water is changed to warm. After complete warming, the phytophthora fungus in the fruits dies, which means that they can be laid in a dark place for ripening, without fear of the development of rot. Also, unripe tomatoes, after cutting off damaged parts, can be used for canning;
- It is impossible to lay tops damaged by late blight on compost, this will contribute to the preservation of the fungus and infection of plants next year;
- It is possible to collect seeds from infected tomatoes for sowing next year, only if they are treated with antifungal drugs before sowing in the ground.
Let's summarize
Thus, it is better to fight late blight at the "distant approaches", by treating the seeds, the soil before sowing the crop, taking proper care of the plants planted in open ground and taking regular preventive measures to protect the plants from this disease. In case of infection, it is very important to timely detect the problem and remove damaged leaves and fruits of tomatoes, treat the bushes with special substances. Vegetables that have been "hit" by phytophthora should not be thrown away immediately, because with proper subsequent processing, they can be partially eaten in canned and even fresh form. In general, the fight against late blight requires attention and knowledge that will help defeat the "enemy".
