Phytophthora of tomatoes: signs of disease, prevention, treatment, drugs

Phytophthorosis is a real scourge of plants of the Solanaceae family. This is one of the most unpleasant phenomena, which from year to year, brings a lot of inconvenience to summer residents, truck farmers. Tomato late blight is a fungal disease that starts on separate bushes and quickly covers all the plants. The sickly tomatoes gradually become covered with brown spots. First, the leaves suffer, then the stems, the fruits. Just a few days, the whole crop dies. If you do not handle every bush in good time in time, then you can forget about homemade tomatoes.


  • Signs of the appearance of late blight of tomatoes
  • Prevention and treatment of late blight of tomatoes
  • Fungicide Strobi will help protect tomatoes

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Signs of the appearance of late blight of tomatoes

Spores of phytophthora, falling on the plant and soil, with strong gusts of wind, from the tops of infected plants in warm, humid conditions spread rapidly. Within 3-16 days the development of the disease begins.

Since the plants are affected in a different time interval and unevenly, the initial stage of bluish flow may pass unnoticed.Over time, on the leaves, stems there are dark spots of brown or grayish-brown hue, which spread rapidly.

In conditions of high humidity on the underside of the affected leaves, a white fluffy coating appears on the stems.


Dark fuzzy spots form on the fruits, which can merge with each other, gradually spreading over the entire surface. Fruits are often deformed, acquiring an ugly shape.

Initially, the fruits are firm, but with the progression of the disease soften - rot begins. As a result, the fruit completely rot, acquires a characteristic sharp unpleasant odor.

The disease can also manifest itself during the afterbirth (bringing to maturity in the vaults) of green fruits collected before the onset of symptoms of phytophthora. The crop damage without the use of fungicides, depending on the conditions, may exceed 70%.

Usually, late blight is transmitted to tomatoes from closely located potato plantations (spores are washed with water into the soil, they spread to surrounding areas), or from infected tubers left in the ground after the previous exposed blight of culture. If there is late blight in neighboring potato plantations, the disease also occurs in tomatoes within 2-3 weeks.

As a rule, the development of the disease is provoked by prolonged rains (longer than 2-3 days) with concomitant lowering the night temperature, when the difference between day and night temperature is 8-12 degrees. Such differences contribute to an abundant loss of dew, which further increases humidity, including directly on plants. The combination of all these factors creates the most comfortable conditions for the propagation of spores of phytophthora.

Favorable conditions for fungus development are high humidity, low air temperature, fogs. In dry dry weather this disease does not develop at all.

To ensure that plants remain healthy as long as possible, it is necessary to withstand large intervals between planting them, avoiding the thickening of the rows, periodically remove the lower coarsened leaves, mulch the soil with the rotted sen. Plant the plants of the Solanaceae family best at the root, so that they do not get wet completely.

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Prevention and treatment of late blight of tomatoes

Although I have subtitled the words about the treatment of tomatoes from late blight, but I must admit that this treatment the disease is almost indestructible, one can only delay, slow down its development, or prevent it appearance. That is, the main thing here is preventive measures.

In the event that the disease is clearly visible to the naked eye, most of the crop, alas, will die, so you need to constantly monitor the weather forecast. As soon as the air temperature drops below 15 degrees Celsius, rains will be affected, immediately you need to spray.


After finding the first signs of the disease should be in time to remove the affected leaves, burn them, Remove the fruits green for dosage, thoroughly washing them, disinfecting in water at 60 ° C 2-4 minutes. Spraying should be carried out regularly with preparations against late blight. This can save a certain part of the crop.

To prevent or delay the development of late blight, fungicides help - they are chemical or biological preparations for combating fungal diseases. Biological - Phytosporin (5 g per 10 liters of water), Ecosil (15 drops per 3 liters of water). Chemical - Bordeaux liquid, Ridomil Gold MC, Tatu, Quadrice, others.Using chemical preparations, pay attention to the waiting time, written in the instruction, after which the action of the chemical is neutralized - the fruits can be eaten.

To prevent late blight, you can sprinkle it with milk whey immediately after planting the seedlings in a greenhouse or open soil. The serum contains lactic acid, lactic acid bacteria, which suppress the growth, reproduction of fungal spores of phytophthora. But you need to do this regularly - every 7-10 days. There is evidence of many gardeners that one dairy whey, without the use of chemical protection, has been saving their tomatoes from late blight for several years.

I want to warn, home or market serum with high fat content should be diluted with clean water. The fatter the serum, the more water you need to add. Milk fat clogs the pores of plants, they can not breathe. Sometimes it is enough to dilute sometimes:.

The same applies to the home whey obtained from long-sour milk - it contains a lot of acid - you can get an acid burn of the leaves.

I use the store, sometimes I buy on the market from the sellers of cottage cheese. I taste the store taste - if not sour, and the fat content is not more than 1%, then I do not dilute.

By the way, the whey contains microelements necessary for the development of tomatoes. This is an excellent top dressing.


Approximately two times per season - once for seedlings and once in the flowering period - in the serum for spraying I add a few drops of iodine - a calculation of this - 10 drops of iodine per 10 liters of whey. Iodine will not protect tomatoes from late blight, but it will help a more abundant, friendly setting of fruits.

Summer residents, truck farmers with experience recommend to process bushes every 2 weeks, and during frequent rains at least once a week. Spraying should be done in the evening after sunset, or early in the morning. In addition to leaves, stems, fruits, it is desirable to water the fungicide soil under the plant, so that the fungi living in the ground, died, did not multiply, did not develop.

The risk of disease of tomatoes with late blight is increased if the crops are planted in soil with a high nitrogen content. In such cases it is recommended to additionally apply fertilizers with the addition of potassium and phosphorus, which enhance immunity. Sometimes eggplants, peppers are exposed to this disease, so they should also be treated, like tomatoes.

It should be noted that phytophthora has the property of adapting to chemicals, because of which it is necessary to alternate at least 2 drugs, which are based on various active substances.

It is said that tomatoes from late blight can protect the copper wire wrapped around the plant, or a copper wire ring stretched through the stem. But I did not do it myself, because I doubt that the stems of the stem for the plant will be harmless.

When late blight has already affected tomato leaves by 60-70% - it is urgent to save fruits - treat them with a solution of table salt (1 kg per 10 liters of water). But this is the most extreme measure. Used to save fruits. Salt will kill all the leaves, infected and healthy - the phytophthora will not pass to the fruit. And those who have managed to get started by this time will be able to mature.

Since the fight against already infected plants is ineffective, crop damage can usually be only partially reduced, maximum attention should be given to preventive measures.

To ensure maximum protection of culture against late blight, a number of agricultural measures should be carried out:

1) Choose for planting resistant to late blight varieties of tomatoes.

2) Observe the conditions for proper crop rotation: crops that are prone to the same diseases should be planted in the same place no earlier than 3-5 years.

3) Observe the spatial isolation of crops exposed to late blight.

4) Observe the necessary distance between the holes when planting seedlings: for early compact varieties not less than 30 cm, for later ones - 40-50 cm, distance between rows not less than 70 cm.

5) To prevent the defeat of late blight of tomato plants by late blight, do not plant open ground plants near the greenhouses.

6) With an increased level of humidity in the greenhouse, provide plants with ventilation, remove unnecessary shoots, lower leaves in time.

7) Use only healthy seed for seedlings.

8) If there are signs of damage to the tops of potato by late blight, plant tomatoes with special fungicides.

9) Treat fungicides planting tomatoes before the beginning of the season of prolonged rain.

10) In time to remove weeds, lower leaves, to conduct pasynkovanie.

11) Do not exceed the norm of nitrogen fertilizers for tomatoes, since excess nitrogen reduces the resistance of the disease to late blight.

12) Watering early in the morning in the holes, do not allow moisture to enter the plants.

13) Timely apply fertilizers containing phosphorus, potassium to increase the resistance of tomatoes to disease.

14) Choose for planting early, early ripening varieties of tomatoes that ripen before the rainy season and, accordingly, before the emergence of favorable conditions for the development of late blight.

15) In regions with high humidity, carry out preliminary spraying of tomatoes with systemic contact fungicides, which significantly reduces the risk of late blight development.

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Fungicide Strobi will help protect tomatoes

Every gardener, a lover of tomatoes knows what harm is caused by prolonged rains and cold dew in late summer, both to plants in the open ground, also in a greenhouse.

Since tomatoes are my favorite garden crop, I plant them a lot, at least 100 bushes. Over the past few years I have used various means of protection, so I want to share my opinion, experience of using the Strobi fungicide.

At once I will say that the remedy is strong, effective. Of the disadvantages, it can be noted that the drug Strobi is toxic. I used it before, I still use it, Phytosporin - I was happy too, but I like to experiment - I decided to try this year Strobi, since the beginning of the garden year was very wet, I was afraid that my tomatoes could not stand the coolness, frequent rains, fall ill phytophthora. But it did. Applied Strobi only once - late blight was not.

Of course, I tore off all the leaves on tomatoes that I did not like, with spots, dry tips. Even some fruits did not regret.

Now I will tell you how I prepared the solution. In the bag Strobi there are small granules - almost a powder. One packet (2 grams) is enough for a bucket of water. This solution is enough for me to spray 100 adult tomato bushes.

First, a film appears on the surface of the water when the solution is prepared, but with constant stirring it disappears.

The instruction warns of safety measures when preparing the solution - after all it is toxic. I cooked it with gloves and glasses to avoid accidental drops on the skin, mucous.

The term of the protective effect of Strobi is 10-14 days. The substance is highly degradable in soil, has minimal toxicity to animals. This is good, as in the garden I have free hedgehogs, neighboring cats who like to rest between the beds in the shade during the summer heat.

Spray I try not only the upper surface of the leaves, but also the bottom one.

The biggest plus of Strobi is that it is effective at low temperatures - they can be sprayed even on wet leaves from the rain. And it will be useful as at the beginning of the disease, as well as in its midst. But just the cold wet weather creates conditions for the development of late blight. I do not know of other drugs with such properties. That is, there is hope that this drug will be able to defeat late blight.

Strobi is also used on other plants: apple, grapes, pears, flowers (especially on roses). But while I saved them only tomatoes. And I did it.


A minus this drug - only one - after all it's a chemical drug.

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