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To grow a rich harvest of cucumbers, you need to know not only the features of the agrotechnics of this plant, but also diseases that can cause irreparable harm to the plant and destroy the entire crop.
Types of cucumber disease
Diseases that affect the cucumber liana at different stages of its vegetation can be divided into three groups.
- Fungal diseases.
- Bacterial diseases.
- Viral diseases.
Fungal diseases of cucumbers
The most common fungal disease of cucumbers is powdery mildew. The reason for its appearance on the leaves is sudden temperature changes, excess nitrogen in the soil or lack of potassium. Sick plants are covered with white powder, lag behind in growth and gradually dry up.
Downy mildew or peronosporiosis arises as a result of high humidity, with watering with cold water, a sharp temperature drop. First, brown spots appear on the leaves, which dry out after a few days. On the back of the leaves there are fungal spores. They are carried by wind and pests to neighboring areas. The disease occurs from the fungus infected with mycelium of plant debris or seeds. Provoke the disease high humidity and watering with cold water, as well as sharp changes in day and night temperatures. It manifests itself in the period of fruiting.
To dangerous fungal diseases of cucumbers should also be credited with white rot, olive spotting, root rot.
Bacterial diseases of cucumbers
The main signs of bacterial wilt (the causative agent is Erwinia tracheiphila) is:
- sharp wilting of the plant;
- the appearance of a white sticky mass (similar to saliva), which is released from the stem;
- leaf spot and wilting.
The virus remains on the remains of the stem until next year. If signs of bacterial wilt are seen, all dry stems must be burned. Planting melon crops in this area is contraindicated 5-6 years. Seeds harvested from such plants are also carriers of the disease.
The causative agent of wet rot is the bacterium Pseudomonas burgeri Pot. The source of infection is untreated infected seeds. Often the disease proceeds slowly and begins to progress only with a decrease in air temperature. The owners complain about a bad variety or freshly harvested seeds, because the crop shortage in this disease can be 40%.
The first signs of wet rot:
- slow growth of shoots;
- Withering and drying of the lower leaves;
- large amount of a void;
- ugly shape of the fruit;
- watery shell of the fruit and oil spots on the leaves;
- rapid loss of turgor during lunch;
- softening of stems and vascular stimulation;
- brown mass inside the flesh of the cucumber.
Cucumber diseases spread very quickly at high humidity. The greenhouse plants suffer the most from this virus.
The angular mottling of leaves causes the death of cucumbers in a short time and is considered the most dangerous disease, as it is quickly transferred from one plant to another. The infection spreads through the wind, drops of water, pests and infected seeds. The disease is characterized by the appearance of brown spots on the leaves and fruits, which dry the tissue for several days. Most rapidly, the bacterium multiplies in warm, humid weather.
When vascular bacteriosis is affected, the fruits lose their flavor and commercial qualities. For food, they are unsuitable, because they become wooden. The infection spreads through contaminated seeds and plant debris.
Viral diseases of cucumbers
For viral diseases of cucumbers is characterized by a change in the color of the leaf. It has spots that resemble a mosaic, and the sheet itself is twisted and wrinkled. All viral diseases are transmitted by seeds or carried by pests. Before planting, the seed is recommended to warm up at a temperature of +70 degrees for three days.
Cucumber mosaic appears after 25-30 days after planting on young leaves. On the sheet there is a patchy yellowing, it is deformed. If you do not start fighting the disease, then in a few days, the fruits will also be infected. The apiary of cucumber mosaic is aphid.
White mosaic on cucumbers is manifested in the form of white and yellow star spots. Often the whole leaf whitens, and the fruits are stained white. Infect the plant with a white mosaic virus only by contact method and seeds.
Green mosaic can be mistaken for a common type of fungal virus, but it affects only the young leaves. They appear vesicular growths, mosaic yellowing, wrinkling. Plants grow poorly, the ovary dries and crumbles.
How to deal with fungal diseases of cucumbers?
The most successful fight against the disease is the absence of disease. To achieve this result preventive measures will help. What do we have to do?
- To observe a crop rotation.
- Adhere to regular watering with warm water.
- Loosen the soil.
In the fight against fungal diseases, the spraying of cucumbers with infusion of mullein, marigolds was well established.
When infecting with powdery mildew, such drugs as "Topaz "Quidris" are excellent. "Oxyhom".
If the first signs of the disease are seen with downy mildew, then it is necessary to stop fertilizing with mineral fertilizers and sprinkling plants with a solution of potassium permanganate, tincture of milk serum. In acute phase, such drugs as "HOM "Kuprosat "Ridomil Gold "Polycarbacin" help. These drugs have an excellent effect in the fight against root and white rot, olive spotting.
Methods of fighting bacteriosis in cucumber disease
Bacterial diseases are the most common and every trucker needs to know the main rules of plant protection from viruses of this group. Preventive works allow to protect young plants at the initial stage of their vegetation.
- Pre-treatment of soil from diseased bacteria.
- Disinfection of seeds before planting (soak for 12 hours in a dark solution of potassium permanganate).
- Regular weeding of weeds and removal of their debris from the bed.
- Fight pests that are the carriers of infection.
- Proper watering of plants with warm, constant water: pour water into the furrow, and not under the root of the plant.
- Spraying cucumbers from pests.
- Respect for crop rotation: return cucumbers to the site only four years after melons and gourds.
- In the greenhouse, the appearance of bacterial diseases is directly related to the formation of condensate. To avoid a large amount of droplet moisture, during the period of temperature fluctuation, it is necessary to use the room heating at night.
And if you can not protect the plants from infection? Than to process cucumbers from illnesses to save a crop? Help medesoderzhashchie drugs: "Kuproksat Bordeaux mixture. Treatment should be done two times, with an interval of 10-12 days.
Fighting the types of viral mosaic
The best way to deal with viral mosaic is prevention.
- Soak the seeds before planting in disinfectants or warm up at a temperature of +70 degrees.
- Destroy all plant remains on the bed, after harvesting.
- Combat aphids and other insect pests.
- Disinfect consumables.
- Water with warm water in the furrows.
- Tie the plants to the support.
- Monitor the quality of the soil.
- Scraping sick plants.
These rules will help to avoid infection with a viral mosaic, but if the plant is sick, then do not immediately resort to chemical drugs. Tinctures from scales of onions, dandelions, tobacco, garlic will help to cope with the problem.
To know exactly what kind of virus you are dealing with, you need the help of an agronomist. You can use the Internet or books on vegetable growing, which shows the disease of cucumbers in pictures and describes the characteristics of each type of infection and ways to deal with them.