Cucumber leaf diseases and treatment rules

In order to ensure healthy growth and good fruiting of vegetable cucumber culture, it is necessary to start the prevention of plant diseases in time, and also be able to carry out treatment. In this article we will consider the most common diseases of cucumber leaves and methods of combating them.

Cucumber leaves are involved in the processes of respiration and water exchange. They, like light ones, carry the main load, producing the necessary substances in the process of photosynthesis.Cucumbers are subject to such diseases as powdery mildew, peronosporosis (downy mildew), cladosporia (brown olive spot), sclerotinia (white rot), gray rot, root rot, anthracnose (medyanka) and chlorosis.

Anthracnose (verdigris) is transmitted through the soil and parts of diseased plants. The disease also migrates with seed. Medyanka in the first stages appears on the leaves in the form of icteric spots with marble veins, which, upon detailed examination, turn out to be cracks. Over time, these spots, like rust and burns, swell.

If the leaves of the plant have begun to dry out and gradually curl up into a tubule, it is possible that the root lesion is called root rot. In a detailed study of the root, you need to make sure it is rotting, determine the degree and then act. Gradually, the plant loses the lower leaves, and then the entire leaf crown of the plant and ovary wilts, the Zelentsy die. This is the stage of complete defeat of the root system.

Root rot - the most common and dangerous disease, because of which the root system of cucumber turns into dust in a matter of hours. The disease is spreading rapidly, growing rotten border throughout the plant since the root. Outwardly, the plant seems to lack water. But the subsequent abundant watering does not contribute to the improvement of the plant, but only strengthens the disease.

Gray rot is a real problem in the garden, which appears when the soil is humid when the air temperature drops. It affects flowers, fruits, stems, leaves and even the roots of plants. Fruits under its influence become deformed and shriveled.

White rot appears on different parts of cucumber bushes in the form of a white foamy mass, which eventually turns black. This is sclerotinia, which eats away plant tissue.

Brown olive rot (cladosporiosis) is characterized by dark foci on the leaves with a characteristic border of olive color. These specks are growing rapidly, capturing all large areas of the green part of the cucumber bush. Then they darken and burst.

Perinospora or downy mildew is familiar to all gardeners. Because of her cucumber leaves are covered with specks and look like freckles. This dangerous common disease can begin at any stage of the vegetable growing season.

When the leaves and stalks of cucumber are covered with rusty and white spots, these are clear signs of powdery mildew. The leaves soon turn yellow and fall off, the fruits and inflorescences begin to dry out, shrink, and the plant stops growing. The disease carrier is a fungus, firmly entrenched on last year’s plant residues. His life span is short and he dies away in July, when the average daily air temperature will be above + 18 degrees.

The most common cause of chlorosis is the lack of necessary elements, such as magnesium, zinc and iron. The disease affects the healthy leaves of cucumbers, which lose their pigment, and with it the ability to carry out photosynthesis. First, the lower side of the frond leaves becomes discolored, then the disease rises higher and higher, affecting an increasing area. The leaves turn pale, dry, and a secondary infection joins the underlying disease.

It is much easier to prevent the disease than to treat it later. There are specific features of protection against each type of disease.

• To protect against peronosporosis, it is necessary to make it a rule to treat the green crown of the bush with whey solution.
• To combat downy mildew, you need to urgently stop watering and fertilizer, and treat the plant with a heated composition of polycarbacin, Bordeaux liquid or copper sulfate. For preparation of Bordeaux mixture, one hundred grams of copper sulphate and hydrated lime are taken and mixed all in warm water.
• When the leaves start to fall ill and fall off, and the vegetables are speckled with weeping sores, an urgent need for a symptomatic treatment of the plant. To combat the cooper, it is necessary to thoroughly treat all parts of the plant with copper sulphate, and then spray it with an aqueous solution with the addition of charcoal.
• Root rot is difficult to determine. It does not manifest itself at the seedling stage. The initial stage of the disease is detected only after transplanting young plants to the garden bed. At the first signs of root rot, which looks like small black spots on the roots, you need to try to save the plant. First, it is necessary to rid it of these putrefactive root inclusions, and then try to prikopat edge part of the basal stem in order to stimulate the growth of new roots.

• To protect the plant from repeated damage, you need to monitor the sanitary condition of the garden, remove weeds in time, and get rid of plant residues. Watering of plants with cold water should also be avoided and spraying with special solutions every week.
• As soon as the gray rot is revealed, it is necessary to urgently sanitize the plant and spray it with fungicides and special means, paying special attention to the cut points.
• To prevent the onset of infection in the early stages, it is necessary to timely treat the seed material with special preparations.
• When a white rot disease appears, it is necessary to get rid of the affected parts as soon as possible, cutting them off, and treat the cut sections with lime composition or charcoal. If the disease has affected the majority of the plant, it must be completely removed from the garden by treating nearby cucumber bushes with a protective compound.
• Cladosporia (brown olive spot) spreads with rain and wind, and remains unnoticed on parts of the plant for a long time. Upon detection, it is necessary to immediately remove the affected vegetables and leaves, process the plant with fungicides, and ventilate the greenhouses. Drip irrigation with cold water should also be avoided.
• When chlorosis on the leaves of plants develop colonies of pathogenic bacteria. It is necessary to treat this disease with the use of complex measures of prevention and therapy at the initial stage of the development of the disease. Otherwise, the plant dies.

For the elimination and prevention of the disease by powdery mildew and other fungal diseases, the drugs “Ordan” or “Ridomil” are used. You can also spray cucumbers with topsin-based fungicides. A well-proven solution with the addition of the drug "Topaz". To prepare the composition you need to mix 10 milliliters of solution with a bucket of water.

As a fast-acting remedy for pathogens and microflora, a drug with copper hydroxide “Chom”, which is made in powder, is suitable. For the preparation of therapeutic composition you need to take 40 grams per bucket of water. Spray cucumbers need from the calculation: one liter per 10 cubic meters of planting. It is also effective to apply Bordeaux or Burgundy liquid.

One of the good tools is a solution of colloidal sulfur. Pre-prepared water composition: 20 grams of sulfur diluted in a bucket of water. In the greenhouse for spraying you need to use a 40% solution, evenly applying its leaves from all sides. For irrigation of garden plantings using a 20% solution of colloidal sulfur, applying the tool in cloudy weather.

Disease kladosporioz (brown olive spot) is afraid of heat, so you need to ensure that in places where vegetables are grown the temperature does not fall below +18 degrees. It is necessary to use everything for this: film, greenhouses and other means.With the appearance of spotting, it is necessary to treat the whole plant with Bordeaux liquid, a solution with the addition of the preparations “Oxyhom” or “Fundazol”.

Sclerotinia or gray rot should be immediately removed from the leaves, fruits and stems of the plant. If the disease is in its initial stage, it is necessary to treat the affected areas with Rovral paste, and then spray the fungicide preparations all over the surface of the plant. Root rot treated "Previkur" and "Fitolavinom."

For the treatment and prevention of chloriosis of cucumber leaves, it is enough to feed the plant with preparations containing nitrogen, iron, magnesium and zinc, as well as to spray the leaves and the subsoil cushion with these compounds.

If the plant is healthy, but for some reason starts to wither, there may be some minor damage to the stem and root system, obtained by mechanical means. In this case, you need to carefully scrape the ground near the roots and examine the plant for cracks in this area and other damage to the stem. The resulting cracks need to be sprayed with an aqueous solution with the addition of copper sulphate and wood ash.

The recipe is this: for half a liter of water, take one teaspoon of vitriol and three tablespoons of wood ash. Everything is mixed and neatly distributed in the affected areas of the plant.

You can also use a dry mixture of activated charcoal, chalk and ash, sprinkling the plant and the ground around the cucumber bush.

For those who are trying less to use chemicals in their garden, so-called folk remedies are suitable for the prevention and control of fungal diseases: cow dung, whey, baking soda and soap. All at once is not necessary to mix. Try to follow the sequence. So, first you need to irrigate cucumber bushes infusion of manure. To do this, one kilogram of organics is mixed with three liters of water. The composition is infused for at least three days, after which it is filtered and diluted again with water.

Soda solution for irrigation of diseased plants is prepared as follows: 50 grams of ordinary baking soda is taken and mixed with laundry soap in 10 liters of warm water. Cucumbers are treated with this compound every five days.

As a preventive measure for diseases, they also use a solution of copper sulfate, which irrigate all parts of the plant, paying particular attention to the root zone. Copper sulphate is also treated with soil cover within the radius of the infected bushes.

Innovative methods of protection against viruses can also be done on their own. Recently, in the fight against bacteria, the cassette method on the mineral cushion has proven itself well. The soil is depleted over time, permanent planting pulls out mineral substances, and fertilizer application has its own nuances and is able to deal with this problem only partially. Plants start to grow poorly, often get sick and stop fruiting. This happens because of the accumulation of various pathogens in the soil.

In this case, it is recommended to practice the cultivation of cucumbers on peat cushions. To do this, use small containers - cassettes of peat composition. You can also use ready-made peat mats, which can be bought at any specialty store.

Cucumber seedlings are first grown in the devices, and then eventually planted in the soil with a pillow. In the future, you should carry out plant care in the usual way, adhering to maintaining a 20-degree temperature at optimum humidity of the air and soil.Humidity of the soil should not exceed 80%, and the air temperature - + 25 degrees.

With root putrid lesions, you can apply an effective method. If the lesion is in its initial stage, the destructive effect is insignificant, and the first signs of the disease only began to appear on the lower leaves of cucumbers, all sick leaves should be cut off, wait until the cuts are dry and lower the plant to the ground. Then treat the wound surface with earth, and then fix it on the support again.

The cause of damage and death of plants is a virus that forms a disease-causing spore, which develops under favorable conditions. Viruses are different in nature. For each disease is characterized by one or another type. In addition, for each species its own temperature scale.

For example, the pythium virus spreads at a temperature of + 12-24 degrees. Phytophthora virus begins its activity at +7 degrees Celsius. But for the development of the disease, the virus must get into a favorable environment. The degree of its damage determines the suitable climate and conditions created by man. When watering plants increases wet environment, and the oxygen content in the soil, by contrast, decreases.

At the same time suffer the roots of plants. This factor significantly weakens the protective function, and the plant is attacked by viruses. Therefore, any intervention in the microclimate should be carried out sparingly. Growing in a permanent place, cucumbers adapt. Factors of light, humidity, watering cycles, water temperature and even wind direction are stored in plants in the memory, activating internal forces for more efficient distribution of resources.

To protect cucumbers from fungal pathogens, you must follow several immutable rules.

• It is necessary to adhere to a crop rotation. Cucumbers on the same bed can be grown only four years after the last fruiting of this plant species. In other times in their place you need to plant other vegetables.
• Removing ripe cucumbers also eliminates the appearance of pathogens.
• Never leave plant residues, torn weeds and affected parts of plants on the beds and in the aisle of the garden. Decomposition products can cause fungus and pathogenic bacteria.
• Do not burn the plant with numerous preparations, and also do not apply too much fertilizer.
• Try to give preference to chlorine-free formulations, and when applying organic matter (manure and compost) strictly, make sure that the fertilizer is well perepelolo and composted within a few months.
• Try to carry out watering with warm water in the sun, without touching the bushes.

• It is also necessary to prevent the occurrence of such a phenomenon as salinization of the soil substrate. This factor extremely negatively affects the development of the root system of plants.
• Seeds before planting should be treated with special biopreparations to give them the necessary immunity and protective properties, as well as to set a positive potential for growth and development.
• Do not dig deep into the soil before planting seedlings. Optimally planted to a depth of one centimeter, with a distance of three centimeters from the ground to the first leaves. It is better to choose cucumber seeds that are resistant to diseases.
• During periods of dressing, it is necessary to ensure free access of oxygen in the root zone, without overloading the ground surface in this place.
• In order to prevent the occurrence of infectious diseases caused by the lack of trace elements, it is necessary to provide the soil with nutrient compositions in time and start irrigating the cucumber seedlings with mineral mixtures as early as possible.

• It is necessary to make it a rule to process and disinfect greenhouses after each harvest. It is also necessary to handle all the working tools and means of fixing cucumber bushes. For disinfection, you can use a solution of formalin, potassium permanganate, iodine solution or other disinfecting compounds.
• You need to try to keep the temperature above 20 degrees. In a greenhouse, this is easy to achieve, and in the open field you need to cover cucumbers with polyethylene or non-woven material to keep warm. Fungi do not multiply at temperatures above a certain level.
• It is best to grow fungal-resistant cucumber hybrids.

About how to treat the spots on the leaves of cucumbers, see the following video.