How to identify diseases of cucumbers in a greenhouse and fight viruses and pests
In greenhouses, you can create optimal conditions for growing vegetables: the required temperature regime, proper ventilation, the ideal level of humidity, illumination, soil saturation with microelements. But even in such conditions, the plants get sick. Most often, diseases of cucumbers in a greenhouse cause infection of whips and fruits with various diseases and pests, violation of agrotechnical standards for growing crops, the use of small greenhouses for planting plants that require different conditions of care.
Healthy greenhouse cucumber
- Soil contamination: the soil in the greenhouse should be renewed every 3 years, removing the top layer of 25-30 cm and replacing it with a mixture of earth, peat, sand. If possible, carry out crop rotation and plant the crop in its original place no earlier than in 2-3 years.
- Improper watering: excessive or insufficient, with cold water, in heat and in bright sun, directly on the plant, and not under the bush.
- Hypothermia or excessive heating of the culture: cold nights (below + 15 ° С), sultry days (daytime temperatures above + 25-30 ° С).
- Incorrect ventilation mode: draft or stagnant air in the greenhouse.
- Lack of nutrients in the soil: depletion of the soil, insufficient application of mineral, organic fertilizing.
- Excess nitrogen in the soil under the vine.
Diseases of greenhouse cucumbers and their causative agents
If, with proper care and strict adherence to all agrotechnical conditions, the cucumbers in the greenhouse begin to hurt - the leaves turn yellow and dry, and the fruits are deformed - it means that they are infected with a disease (fungal, bacterial, viral) or are exposed to pests.
Diseases (fungi, viruses) and pests can cause significant damage to the crop, up to its complete loss.
Regular inspection of the leaves
The main diseases of cucumbers in the greenhouse are:
- Rot: white, gray, root.
- Anthracnose.
- Peronosporosis (downy mildew).
- Spotting (cladosporium, bacteriosis).
- Fusarium wilting of cucumbers.
- Viral diseases (green, white mosaic).
Powdery mildew and its prevention
Powdery mildew is the most common disease in greenhouse cucumbers. The activation of its causative agent - the fungus Erysiphe cichoracearum and Sphaerotheca fuliginea - is facilitated by cooling and heating the air in the greenhouse, fluctuations in humidity. The culprits are infected plants (weeds, plant debris), spores of the fungus, seedlings can become infected through the infected soil. Yield losses from powdery mildew in a greenhouse can reach 100%.
Powdery mildew on cucumbers
The disease manifests itself as a whitish-grayish dusting on the outside of the true leaves of cucumber lashes (spots that look like dusty with flour), then a whitish tint appears on the back of the leaf plate. The bush dries up and dies.
- thorough cleaning of the soil from plant residues;
- timely removal of infected leaves and plants;
- the use of pathogen-resistant hybrids.
To combat, the method of irrigating the bushes with a solution of urea (1 l) and a liquid mullein (1 l) or a weak solution of potassium permanganate (stir a few crystals in 10 liters of water until a pink tint is obtained) is used. After removing the infected leaves, the lashes can be treated with a soda-soap solution (4 g of soda ash, 4 g of soap, 1 liter of water), irrigate twice, at an interval of 7 days.
Peronosporosis or downy mildew
The causative agent of peronosporosis is the fungus Pseudoperonospora cubensis Rostowz. The main causes of infection are improper watering - with cold water, sudden changes in temperature, high (85% and higher) humidity. The seedlings infected with peronosporosis are disproportionately stretched, the ovaries are small, crooked. The leaves of an adult plant from the outside are covered with yellow spots in the form of a polygon, from the inside - a grayish-purple hue, wither and fall off.
Downy mildew
Plants affected by the fungus should be removed from the soil and burned, and the topsoil (25-30 cm) should be replaced immediately. Spores of the pathogen perfectly tolerate wintering in a greenhouse; with an increase in humidity, they actively multiply and infect healthy cucumber lashes.
As a preventive measure, you can irrigate the soil in the greenhouse with a decoction of tansy.
- Pour about 30 g of grass (dried or fresh 300 g) with boiling water (about 10 l), do not boil, let it brew for about a day.
- Boil the resulting broth for about an hour and a half, cool, spray over the greenhouse.
- You can sprinkle the ground around the roots of the bushes with ashes of fruit trees, in winter, treat the soil with Bordeaux liquid.
Treatment of diseased lashes consists in spraying them with combined fungicides, an aqueous solution of freshly slaked lime and copper sulfate (100 g of each substance per bucket of water).
Anthracnose (copperhead) and the fight against it
The causative agent of the disease is the fungus Colletotrichum lagenarium, it infects cucumbers already at the seedling stage. On greenhouse bushes, the disease manifests itself in the form of yellowish, brown, round spots on the outside of the leaf closer to its edge. The affected tissue of the leaf plate falls out, forming numerous holes.
Sometimes the spots can merge, as a result of the defeat, the sheet is torn. If the plant is not treated in time, the disease can also affect the fruits. Brown spots appear on them, pressed into the depth of 3-5 mm, their seeds cannot subsequently be used for seedlings.
Anthracnose (copperhead) on leaves
The plant is infected through the soil and organic debris, so it is especially important to remove diseased cucumber lashes in time. As a prophylaxis for the disease, it is recommended to replace the top layer of the soil and pickle the seeds before planting in the soil.
To combat copperhead, 1% Bordeaux liquid is used, which is sprayed with infected leaves. With the root form of the copperhead, this solution is poured under the root. Experienced gardeners recommend sprinkling the affected areas with crushed coal and lime.
Rot and their types
Like powdery mildew, rot is a disease in greenhouse cucumbers that is caused by fungi. There are types of rot: white, gray, root. A symptom of root rot infection of cucumbers is yellowing and wilting of the leaves, while the stem at the root cracks and turns yellow. When planting seedlings in a greenhouse, it is recommended not to deepen the stem into the ground, not to huddle it, not to sprinkle it with soil - this way you can save the bushes from disease.
Cucumber rot - types
For the treatment of root rot, a solution of copper sulfate and honey is used (1 tsp., 3 tbsp. L., 0.5 l of water). They lubricate the stem of a cucumber to a height of 12 cm. The plant that has died from rot must be urgently removed from the greenhouse, and the hole and the soil around it must be watered with a solution of copper sulfate.
Root rot of cucumbers
Sometimes in thickened plantings on cucumbers, gray slimy spots can be seen - this is gray rot spreading. Poor greenhouse ventilation, excessive watering, cold water provokes disease. Having found such spots on one plant, it is necessary to check all the others, treat or remove the infected ones and adjust the air humidity. Treatment of gray rot consists in sprinkling the affected areas with a mixture of copper sulfate and wood ash (1 tsp. To 1 tbsp.).
High humidity can also activate white rot - with this disease, the roots, leaves, fruits of vegetables are covered with a white bloom, resembling cotton wool in structure. With the development of the disease, the plaque turns into mucus.
White rot in neglected form
Parts of the cucumber vine infected with white rot should be cut off, and the cuts should be sprinkled with lime or copper sulfate. After removing diseased plants, the soil must be treated with a weak solution of potassium permanganate.
Spotting and its danger
Cladosporium disease (brown spot) can destroy an entire cucumber crop in a matter of days. Infected plants and fruits are covered with brown spots, from which liquid oozes, they are not suitable for food. The disease develops in greenhouse conditions with excessive humidity.
For treatment, you should examine all the bushes, remove diseased ones, stop watering for 5-6 days, open the doors and windows of the greenhouse and arrange total ventilation. It is necessary to set the optimal temperature regime for cucumbers: +25? C during the day, +23? C at night. It is recommended to spray the lashes with a solution of 1% Bordeaux liquid.
Brown spot of cucumbers
Bacteriosis (angular spotting of leaf blades) spreads in greenhouse conditions of high temperature and humidity. First, spots appear on the leaves, which “grow” and join together. The tissues of the leaf plate die off, fall off and only veins remain on the leaf. When the disease spreads, the plant dies. In case of untimely treatment of bacteriosis, 50-70% of the crop may die. The disease rate for other plants in the greenhouse is very high.
Prevention of bacteriosis consists in the use of high-quality seed material, seed dressing before planting in the ground. After the detection of cucumbers diseased with bacteriosis and their removal from the greenhouse, the frame, the frame should be disinfected with lime.
Dangerous fusarium wilting
Fusarium wilting is a dangerous plant disease caused by a fungus that infects the fibrous bundles of cucumber vines. At the same time, the supply of nutrients to the tissues of the plant stops, and it quickly withers and dies at any stage of growth.
Due to the rapid development, this disease of cucumbers is not treated, therefore it is important to timely prevent it not only in greenhouses, but also in open beds. As a preventive measure, you can treat the soil after harvesting with a solution of potassium permanganate.
Fusarium wilt of cucumbers
Cucumber viral diseases
Green and white mosaic - viral diseases of cucumbers in the greenhouse. Infection of plants with green mosaic is more dangerous - it affects leaves and fruits, which acquire a variegated mosaic color. In case of white mosaic disease, white and yellowish stripes form on the fruits.
Viral diseases are practically not cured. It is recommended to transplant young shoots to a new place, old ones - just to be removed. Infected fruits should not be eaten or given to pets. Such a crop will have to be disposed of by destruction.
Green mosaic on cucumbers
Dangerous pests of cucumbers
Growing cucumbers does not require a lot of costs and hassle, the main thing is to protect the plants from pathogens and pests that live in the ground. The main pests of cucumbers in the greenhouse:
- Putin tick;
- greenhouse whitefly;
- slugs;
- bear;
- beetle larvae.
Aphids on cucumbers: how to distinguish
The easiest and most environmentally friendly way to get rid of aphids is to irrigate and wash the leaf plates with a soap solution. You can water the lashes with infusion of garlic, onion husks, celandine.
Aphids on a cucumber leaf
Drying and wilting of cucumbers in a greenhouse can be caused by a spider mite, which envelops the entire bush with a small cobweb, preventing the penetration of oxygen and sunlight to the tissues of the cucumber vine. Thus, the process of photosynthesis is disrupted, the plant withers. In addition, the spider mite, like other pests of cucumbers in the greenhouse, feeds on juices from the leaves and stems, stopping the further development of the cucumber lash.
Treatment for spider mites must be immediate, otherwise the entire planting may die. First, you need to remove the leaves infected with the mite and spray the bush with soapy water. If more than 50% of the green mass is infected, it is recommended to remove the diseased plant from the greenhouse and burn it.
You can also use other folk methods: put a jar of chopped garlic or poured turpentine under the bush, wrap the bush with foil and leave for a couple of hours. Treatment of a plant from a tick should be carried out twice or three times with an interval of 2-3 days: at high air temperatures, the insect reproduces at an accelerated rate, the tick larvae hatch after 3 days and the likelihood of re-infection is high.
Spider mite on cucumbers
Greenhouse whitefly
The insect infects the leaf plate of the cucumber vine, sucking out the nutritious juices. The leaf turns black, withers and dies. More often than not, the winged flap settles on the lower part of the leaf plate. To get rid of it and save the plant, you should wash the leaves with soapy water, then rinse with clean water. Given that the insect does not hibernate in the ground, most often the pest enters the greenhouse along with the infected seedlings. Therefore, it is recommended to carefully inspect all plants before planting in the ground.
With minor plant infections, you can irrigate the bushes with infusion of garlic or dandelion. Grate or chop 100 g of garlic, pour 0.5 liters of water and leave in a dark place for 5 days. Then dilute 5 ml of garlic infusion in 1 liter of water and irrigate the infected areas.
Whitefly on cucumber leaves
Pests of cucumber seedlings
Pests of cucumbers in the greenhouse attack and damage not only formed cucumber whips and fruits, but also newly planted seedlings. The bear and the larvae of click beetles feed on young, immature roots. The seedlings dry up and die.
Among the popular methods of dealing with a bear there is this: pour an aqueous mixture of black pepper or a vinegar solution into the passages.
The slugs eat the green mass of the shoots, causing it to dry out. As the main method of dealing with slugs, it is advised to leave cut potato tubers with small indentations in the beds overnight. In the morning, they are thrown out of the greenhouse along with the slugs.
For the operative treatment of diseases of cucumbers in a greenhouse, it is necessary to learn how to identify their pathogens, a photo will help with this.
For the prevention of diseases, it is important to organize the correct temperature regime and ventilation, maintain an optimal humidity level, and timely replace the soil and disinfect it.
Photogallery of cucumber diseases
Diseases of cucumbers. Part 1 with photo
Diseases of cucumbers. Part 2