There are many signs of cucumber diseases, some of which can confuse even an experienced gardener. But if you carefully examine the bush, it will be easier to figure out how to preserve the harvest.
All diseases of cucumbers can be divided into several groups: fungal, bacterial and viral. Often gardeners do not even realize that their plant is sick, because it is not easy to calculate and determine the disease. Let's carefully look at the leaves, stems and fruits of the cucumber and try together to determine what is wrong with the plant.
Causes of disease development in cucumbers
Violation of the rules of crop care and violation of agricultural practices can serve as fertile ground for the development of various diseases. These factors include:
- Insufficient or excessive watering. Excessively moist soils provoke the development of rot, while dry soils serve as a habitat for many pathogenic bacteria.
- Deficiency or excess of nutrients, macro- and microelements introduced during feeding. Both conditions are extremely harmful to the plant, reducing its immunity and susceptibility to diseases and pests.
- Poor weeding (or lack thereof). Weeds attract the attention of microbial-carrying insect pests and serve as a breeding ground for them.
- Lack or insufficient loosening. The hard crust that forms on the soil surface prevents the normal penetration of air, moisture and nutrients to the roots.
- Excessive planting density, which contributes to disruption of air exchange and the creation of conditions optimal for the development of various pathologies.
- Insufficient disinfection of the soil, equipment used, and cultivation facilities (or lack thereof).
- Poor quality treatment (or lack thereof) of pruning areas (pinching, pinching), which contributes to the spread of infections.
Such moments include the difference between night and day temperatures, as well as sudden cold snaps. These factors are not always predictable, but have an extremely adverse effect on the development of diseases, especially in combination with rain.
Features of diseases in greenhouses and open ground
There are many diseases in cucumbers. In a greenhouse, compared to open ground, they are more common, and their harmfulness increases.
Powdery mildew is very harmful to greenhouse cucumbers , instantly spreading in a closed space. In open ground, the disease is less common and spreads less rapidly. Infection of cucumber plantings and germination of spores occurs during sharp fluctuations in day and night temperatures, prolonged cold spells, and high humidity. On the street, the disease appears 3-4 days after heavy rains.
Downy mildew most often affects cucumbers growing in a greenhouse. The spread of the disease is facilitated by an average daily air temperature of 18-22 degrees, in the presence of dew, fog, and precipitation for 8 hours.
The disease spreads when soil and air temperatures are below 18 degrees and high humidity.
Fusarium develops when air and soil temperatures drop.
Bacteriosis most often spreads in greenhouse conditions. The disease manifests itself at high soil and air humidity. The development of the disease is favored by high humidity and temperature.
Mosaic diseases of cucumbers are common both in greenhouse conditions and in open ground. They appear during sudden changes in air and soil temperatures and thickening of cucumber plantings.
Greenhouse cucumbers are most often affected by white rot. The disease spreads when there is high humidity in the air and soil and insufficient ventilation of the greenhouse. Sudden temperature changes and watering with cold water provoke the disease.
Cladospora blight often occurs in a greenhouse. The main reason for the appearance of the disease is cold weather at night and sprinkling of plants with cold water.
Many diseases persist in the ground for several years, as well as on plant debris and in plant seeds. Replacing the soil in the greenhouse, digging, fertilizing, removing weeds from the beds and treating the soil with protective drugs help prevent the occurrence of diseases.
Prevention of cucumber diseases
Compliance with all of the above requirements is the most important preventive measures to prevent diseases. Additionally, preventive measures should include:
- Timely removal of all lifeless areas of the plant and disinfection of the cuts.
- Compliance with crop rotation rules from the point of view of predecessors:
- favorable - peas, cabbage, peppers, tomatoes, radishes, beans;
- unfavorable - watermelons, zucchini, cucumbers, pumpkin.
- Planting cucumbers in one area no more than every 4 years.
- The use of green manure plants (mustard, oats, rye, etc.) after harvesting with their further digging and embedding of seedlings into the soil.
- Use of high-quality seeds and seeding material.
- Destruction of aphids and insects that carry them.
- Remote planting of cucumbers from:
- watermelons and melons (common pollinating insects);
- garden flowers, the sweet juice of which serves as a breeding ground for aphids.
Regardless of the cause of the lesion, all diseased crops must be removed and destroyed, followed by appropriate treatment of the area. In case of mild infection, the affected areas are trimmed and the cut areas are treated with disinfectant solutions.
The use of folk remedies
In addition to treating cucumbers with chemical and biological drugs, there are many folk or “grandmother’s” recipes for any ailment.
These methods have a number of advantages. They are less dangerous to human health, and some are just as effective. In most cases, the ingredients for preparing solutions can be found at home. And the price of the products is several times lower than store-bought ones.
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Regular greenery can be an effective way to combat fungal infections. You need to make a solution (10 drops of brilliant green for 10 liters of water) and mix. Apply the solution from a spray bottle. Or water the ground.
Lubricate the root area with a solution (200 ml of water and 100 ml of brilliant green). The procedure is convenient to carry out with a regular brush. It protects against most types of fungal infections that develop in the soil, especially root rot.
Iodine
One of the common means of combating cucumber diseases is iodine solution. It is especially effective in treating root rot. Two parts of water are mixed with one part of iodine and the base of the stem is treated 10-15 cm upward.
The treatment is done once every 3-4 days until the signs disappear completely.
Rotten hay
This is another forgotten but effective treatment. The main advantage of the method is that rotted hay forms substances with signs of antibiotics, which destroy most pathogenic and harmful bacteria. During the decomposition of grass, a mass of beneficial microorganisms is formed. They enrich the soil and help seedlings fight various diseases.
How to prepare mother culture at home:
Add 2 liters of water to 300 g of rotted hay. To reduce the acidity level, you can add 2 teaspoons of chalk there. Boil for 10-15 minutes, strain. Bacillus subtilis dies when boiled, but the spores remain. Infuse the resulting liquid for 2-3 days in a dark, warm (24°-30°) place. During this time, disputes germinate.
How to prepare mother culture in the country:
This is done like this: 1 part of rotted hay is poured with 10 parts of boiling water in a basin. When the water has cooled to 37°, add 10 tbsp. spoons of lime or chalk. The resulting substance is infused for 2-3 days at a temperature of 24°-30°. It is advisable to do this outdoors.
It is important to remember that direct sunlight kills the beneficial hay bacilli, so it is better to cover the solution with a dark cloth. For prevention, use the uterine infusion in the form of a spray, once every 2 weeks. Required in cloudy weather, but without rain.
Forgotten means
There are many forgotten, but no less effective folk recipes for fighting diseases. Here are some of them:
A solution prepared from whey in a ratio of 1:10 will prevent the infection from spreading, forming a thin film on the affected areas of the plant. This film is harmless to cucumbers. You just need to treat diseased specimens with the resulting solution from a spray bottle.
Herbal infusions: tansy, nettle or wormwood.
Mullein solution is a remedy for many cucumber diseases. One liter of mullein is mixed with three liters of water and infused for three days. Before processing, you need to add three more liters of water to the tincture.
Tincture of ash with the addition of laundry soap is another proven method. It is prepared like this: take a glass of ash per two liters of water and leave for 2-3 days. Add 5 grams of laundry soap to the strained solution. The solution is ready for use.
Gray rot
This is also a disease of cucumbers in the greenhouse, which manifests itself in the form of gray spots of the mucous structure. This is especially noticeable in the leaf axils of the branches. The spread of the disease occurs when the night temperature decreases, cold water is used for irrigation, planting is dense and the greenhouse is poorly ventilated.
When plants are densely planted, a very large number of male flowers appear. One leaf can contain up to 15 barren flowers. Which quickly fade and attack healthy stems.
Formation of gray rot
Control measures: Do not plant plants too densely. If there is a large amount of barren flowers, it should be removed and the vacant areas should be sprinkled with charcoal or wood ash. Do not water when a disease is detected, but check all plants immediately. When fertilizing and watering, do not direct water onto the plants themselves.
The following mixture helps with illness:
- 1 cup wood ash
- 1 teaspoon of copper sulfate
Mix thoroughly and sprinkle the resulting solution onto the affected areas.
If the disease continues to develop, it is necessary to cut off the affected plants and burn them.
If fungal diseases occur in plants, it is better to immediately spray with the bacterial preparation “Barrier” or “Barrier” , especially since they are harmless to people.
Downy mildew
The disease is often called downy mildew. Downy mildew appears on the leaves of cucumbers. On the back side, foci with spores form. The front surface is covered with many small yellowish spots, which gradually grow and lead to drying of the tissues.
Like most fungal diseases, it spreads massively during cold and rainy weather. If the disease is not recognized in time, then within 1-2 weeks you can lose most of the harvest.
An effective measure to prevent downy mildew is spraying the bushes with Fitosporin. If a disease is detected, you should sprinkle the soil in the beds with wood ash and treat the shoots with biological products Trichoderma, Acrobat MC or Gamair.
Advice from experienced gardeners
When choosing cucumber seeds, disease-resistant varieties are selected.
The best prevention of diseases and pests for cucumbers is alternating crops when planting in the same beds. In the greenhouse, if possible, the top layer of soil is replaced or treated with protective drugs.
Crops are planted next to the plants, repelling pests with their smell and attracting beneficial insects.
When planting cucumbers in a greenhouse, good air circulation is ensured, since in the absence of ventilation, moisture accumulates in closed conditions, provoking the development of fungal diseases.
Watering plants is best done in the evening, this avoids high humidity, the main cause of disease development. For irrigation, use settled, not cold water. You need to water the plants directly under the roots, without touching the leaves.
To protect plants from diseases and pests, the best option is to plant them in a permanent place in the form of mature seedlings. Strong and healthy plants resist illnesses more easily.
Timely feeding of plants guarantees their health and high resistance to disease.
Specifics of pests of open ground and greenhouses
In open ground, pests most often spread from neighboring weeds or when seeds are damaged. In greenhouse conditions, a common cause of damage is poorly treated soil before planting and unfavorable environmental conditions.
The reasons for the appearance of whiteflies are weeds, violation of humidity and temperature conditions, poor air ventilation in the greenhouse and improper nutrition.
Spider mites appear when crop rotation is not observed, plantings are overgrown with weeds, or high air humidity.
Aphids most often overwinter on weeds. The pest reproduces in the spring. First, the aphid feeds on the sap of the weeds, and then moves onto the cucumbers. Pests appear in a greenhouse in the spring, and in open ground - from July to August. The main reasons for the appearance of pests are violations of temperature and humidity, poor air ventilation in the greenhouse, weeds, and insufficient nutrition.
Observance of crop rotation and agricultural technology in general allows you to avoid the appearance of any pests.
