Late blight spreads in plantings very quickly, especially in the presence of condensation in greenhouses and sudden changes in night and day temperatures. If the circumstances are unfortunate (weather conditions, inability to regularly care for plants), an outbreak of infection can completely deprive the unlucky gardener of his hopes for a tomato harvest.
Like any disease, late blight is much easier to prevent than to treat.To avoid the use of copper-containing fungicides (HOM, Copper sulfate, Bordeaux mixture, etc.) and pesticides (Quadris, Skor, Magnicur neo), which are sprayed on already diseased tomato bushes, I carry out a whole range of preventive measures that allow you to grow environmentally friendly fruits without toxic substances in their pulp.
Spraying plants with biological agents to prevent an outbreak of infection
For myself, I decided on methods of combating phytopathogens that infect tomato bushes. My main focus is on preventing the spread of fungal pathogens in plantings. To do this, I regularly use Fitosporin-M or its analogues: Phyto Doctor, Mikosan-V 500, BioShield FitoAgro, etc.
Moreover, the first time I use a solution of microbiological preparations is when soaking planting material that I prepared myself. Purchased seeds from trusted suppliers of agricultural products, especially pelleted ones, do not need to be sanitized in a phytosporin solution. In the future, I process tomato seedlings and adult plants transplanted into greenhouses at least once a week. I carry out the last procedure several days before the full harvest of even green fruits (before the onset of frost).
Several times a season I spray adult tomatoes with a solution of iodine and milk. Due to the presence of milk, after the liquid, sprayed with a fine spray, has dried, the tomato leaves become covered with an invisible film that prevents the penetration of fungal spores into the tissue. And iodine, which is a natural fungicide and antiseptic, successfully fights fungal and bacterial plant pathologies.
In addition to fungicidal properties, such irrigations are considered an effective iodine supplement for nightshade vegetables, stimulating the ripening processes of fruits and improving their biochemical composition. To prepare a working solution, simply dilute 1 liter of low-fat whole milk in 9 liters of settled water at room temperature and add 40 drops of pharmaceutical tincture of iodine (5%) to the liquid.
I spray plants with the listed means not only in greenhouses. A healthy ecological situation throughout the entire site is the key to minimizing the development of late blight. That is why, at the same time as tomatoes, I also cultivate a potato plantation, even if it is located quite far from the greenhouse, as well as planting eggplants and bell peppers in open ground and in closed structures.
Proper care of tomatoes in a greenhouse in July and August - prevention of late blight development
In addition to regular treatments of tomatoes with microbiological preparations based on strains of beneficial bacteria Bacillus subtilis 26 D and an iodine-milk mixture, the use of certain agricultural practices is necessary to prevent the spread of dangerous fungal spores in closed structures.
1. Mulching the soil.
A thick layer of hay, straw or dry lawn grass between the rows of tomatoes prevents excess moisture, which inevitably appears after watering. And, as you know, it is in a humid environment that fungi spread intensively, especially when night temperatures drop below +14. In addition, mulch inhibits the evaporation of valuable moisture, reducing the frequency of watering, and prevents the formation of an airtight soil crust, especially on heavy soils.
2. Organization of irrigation.
The best option is to use a groove specially dug between the bushes and covered with mulch for watering. The frequency of watering tomatoes in greenhouses, even in extreme heat, is once every 5-7 days, and the amount of water should be sufficient to moisten the root layer (about 30 cm deep). Surface watering is harmful for tomatoes, as they interfere with the deep penetration of root shoots into the soil.
3. Applying mustard cake under the bushes.
2-3 times a season I always sprinkle the furrows between the rows (directly along the mulch) with mustard cake. The application rate is according to the instructions. After powdering, I immediately carry out scheduled watering with water heated in the sun from a watering can without a nozzle. The presence of mustard powder on the surface and in the top layer of soil effectively prevents late blight and other dangerous diseases of tomatoes.
4. Formation of bushes.
Free air movement in greenhouses where tomatoes are grown minimizes the risk of late blight. All leaf plates located below the first brush are usually cut out by mid-summer, and the bushes themselves are tied to pegs or placed on supports.
In the first ten days of July, I form tall tomatoes, not limited in growth, into 2-3 stems. I regularly cut the rest of my stepsons.
I form low-growing varieties of crops into 1-2 stems.
To improve the ventilation of the plantings, I also cut off the excess leaves of the middle tier, and shorten the remaining ones (by a third or even half). The main rule is not to remove more than three leaves from one plant at a time. The interval between pruning tomato bushes should be at least 5 days.
5. Pinching the tops.
It is necessary to limit the growth of indeterminate varieties of tomatoes, which, as a rule, already reach the greenhouse roof by the end of July. Pinching of the growing point is carried out in August, and in warm regions - in September. This technique allows the fruits already located on 5-7 or more clusters to completely fill the bushes.
As you can see, there is nothing complicated in preventing late blight. Use time-tested methods to combat the main disease of nightshade crops, and you will be able to harvest record tomato yields every season.
