Diseases of cucumbers in the open field and methods of their treatment
Diseases of cucumbers lie in wait for summer residents at every step. Do not relax, because caring for cucumbers is not limited to just planting and growing them. In order for the harvest of cucumbers to be good, you will have to strain yourself, spending a lot of your time and physical effort to provide proper care, prevent possible diseases, and fight diseases and pests.
Powdery mildew
What are the signs of the disease
It is generally accepted that powdery mildew is one of the most common diseases that affects different crops, including cucumbers. The disease "hits" the leaves of the plant. Not so often stems and petioles are susceptible to infection, very rarely - cucumber fruits. If a small white spot is visible on the top of the cucumber, it is powdery mildew.
The spot increases in size, first covering the entire leaf, and then the entire plant as a whole. Gradually, the disease affects the whole plant negatively. It can be seen how the common bush "suffers" when brown whips fall from it. Powdery mildew slowly kills the plant. If it grows in an infected form, then this will lead to a decrease in the quality of the fruit, and the cucumbers will grow much less. Why does the disease appear?
The causes of powdery mildew
- high degree of humidity;
- planting cucumbers without proper care;
- the presence of weeds in the beds;
- systematic changes in temperature indicators;
- when poured with cold water;
- winds, drafts;
- if the planting of cucumbers is carried out at the same place every year.
The disease remains in the ground, on plantains, weeds and on infected plants that have remained in the garden for the winter.
The development of cucumber powdery mildew is also facilitated by sudden temperature changes, high air humidity and dew loss.
How to deal with powdery mildew on cucumbers
Over the years, a large number of all kinds of methods have been developed to eliminate this disease.
It is necessary to plant only strong and resistant varieties of cucumber, as well as its hybrids. If the owner of the site saw the first signs of the disease, the infected parts of the plant should be cut off and disinfected, or burned.
In the event that the disease progresses, the cucumber bush should be treated with ground sulfur (take 30 g per 10 sq. M. Planting).
You can make a colloidal sulfur solution: 30 grams of 0.3% sulfur per 1 bucket of water.
Action: Sprinkle the plants with a mullein.
In order for the plant not to get sick next year, it is imperative to remove all plant residues. It is imperative to dig up the beds deeply.
When signs of powdery mildew appeared on cucumbers, they increase the feeding of the soil with potassium.
When the disease progresses, and the whole garden is already in danger, then poisonous chemicals are used. "Topaz", "Oxyhom" will do. It is necessary to act strictly in accordance with the instructions developed by the manufacturer.
Symptoms of the appearance
On the reverse side of the leaf, a gray bloom with a lilac tint is visible.
And on the face of the leaf, light green spots with a yellowish tint, of an oil consistency appear. Their shape can be round or triangular.
Over time, the spots increase in size and move to the surface of all cucumber leaves.
Infected leaves take on a brownish-burgundy hue. They will become brittle. The leaves eventually crumble, and the stems are exposed.
A disease such as downy mildew differs from a simple one in shade and in the nature of the spots that form. When it is a simple mealy, it is as if someone has sprinkled flour on the leaves. White spots are small. If it is downy, the leaves of cucumbers seem to be burnt by the sun's rays from dew drops. Both the first disease and the second harm the cucumbers. Without treatment, they will die.
Reasons for the spread of downy mildew
The occurrence of this disease may be due to the fact that a certain type of fungi living in the ground begins to actively multiply. They live in soil for about 6 years.
Factors that have a beneficial effect on the growth of fungi:
- Too much humidity;
- Rainy season;
- Fogs;
- Dew;
- Incorrectly chosen planting site for cucumbers (shadow side);
- There is no natural air circulation.
Downy flour on cucumbers develops well when very often the temperature drops and rises sharply. This can happen during the day and at night. The air is completely saturated with water vapor with a difference of more than 10 degrees. Then, at 100% humidity, dew appears on the leaves. It is important, with the onset of night, to cover the cucumbers, or provide them with heating.
Peronosporosis of cucumbers or downy mildew is one of the widespread diseases of this vegetable. This is exactly the disease that can lead to the death of the plant.
Ways to fight
In order for false mealy to “not occupy” the cucumbers, preventive measures must be taken. This is necessary for a healthy and complete harvest. Folk remedies for combating this disease are suitable in order to eliminate the first symptoms and extensive lesions, when the ovary has already formed. Chemicals are applied only until the fruit is ripe.
Preventive measures to prevent this disease
It is much easier to prevent the appearance of the disease than to waste time and energy trying to save the cucumbers, or even lose the crop. To prevent this from happening, the following measures should be taken:
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- Watering is carried out only in the morning. The water should be warm. This is necessary in order for the humidity level to decrease in the evening.
- It is necessary to maintain the temperature at the same level, without sudden jumps. In the daytime, a suitable temperature is +25 degrees, at night - + 18- +21.
- It is necessary to change the place of planting of cucumbers every season.
- The greenhouse should be ventilated as often as possible.
One of the preventive measures to combat this fungus is the selection of those varieties that are resistant to downy mealy. It is worth choosing hybrids of cucumbers that are resistant to it:
- Delpin F1;
- Vicenta F1;
- Anyuta F1.
If we give preference, nevertheless, to varietal plants, then after collecting the seeds, they must be soaked for disinfection in a solution of potassium permanganate (dark color).
The use of special tools
The use of biochemicals and chemicals is recommended even in the period when the seeds are being prepared for sowing. This is easier than taking measures to destroy downy mildew later and losing the crop. The following drugs have proven their effectiveness: Fitosporin-M, Adirin-B and Gamair;
For preventive purposes, so that downy mildew does not appear, it is necessary to make a fungicide solution. Then place the cucumber seeds there for 1.5 - 2 hours. After that, the seeds are taken out, washed under water. Dried. They are ready to be sown in open soil, or for seedlings. 1 kg of seeds is consumed per one and a half liters of liquid.
During the period when the stem is growing intensively, in order to prevent the appearance of downy mildew, it is advisable to spray the bushes with an effective preparation, with a certain frequency. For example, one of these:
- Gamair. Every 14 days. 10 liters are consumed per are.
- Vitaplan. After 21 days. 3 liters are consumed. on ar.
- Profit Gold. After 7 days (or 14). 5 liters are consumed per hundred square meters.
- Fitosporin-M. After 10-14 days. 10 liters are consumed per are.
- Proton Extra. After 10 days. Consumption 10 liters per hundred square meters.
After the drugs have been used to prevent the appearance of false mealy on cucumbers, their condition can deteriorate sharply. To keep them in a viable state, it is worth conducting tests by choosing 2-3 bushes. In the event that they do not feel bad during the day, you can spray this drug over the entire area.
When cucumbers do not give a crop every year, and the fault is simple or downy mildew, then it makes sense to use chemicals both during the ovary period and when the plant bears fruit. Harvest, 7 days (at least) will not be able to collect, since cucumbers, after processing, will be unsuitable for food. But, for the rest of the time, it will be possible to collect and eat delicious cucumbers.
Traditional methods of treating downy mildew
For hundreds of years, people have come up with all sorts of ways to combat downy mildew. This knowledge was passed down from generation to generation. Here are some recipes:
- Garlic broth. Place 75 grams of finely chopped garlic in 1 bucket of water. You can also use arrows. The broth, which has cooled down, is sprayed on the bushes.
- A solution of milk and iodine. Water - 9 liters, milk (0% fat) - 1 liter. Add 10 drops of iodine (alcohol solution 5% concentration). Sprinkle cucumbers.
- Ash tea. Brew in 3 liters of boiling water 0.5 liters. ash. The tea, which has cooled down, is brought to a volume of 10 liters.
For spraying from this disease, any time of the day and any frequency is suitable. If the plant is sick, it should be sprinkled with broths more often. For maximum effect, the weather should be as calm as possible. Plants are also sprayed for prophylaxis. This procedure will not bring harm.
Signs of white rot on cucumbers
Infected areas will develop a plaque of lush white flakes. This is the mycelium of the fungus, which, over time, begins to increase in size. The tissues of the infected areas of the stem become soft and acquire a watery structure. The process of delivery of water and nutrients contained in it from the soil is disrupted. As a result, the plant withers and dies.
Over time, the mycelium here and there becomes dense and dark. This suggests that the sclerocial stage of the fungus has begun. When the cucumber fruit comes into contact with the infected area of the fungus, they become infected very quickly.
Cucumber white rot is found almost everywhere cucumbers are grown. Gardeners especially often encounter it indoors.
How to deal with white rot
The key agronomic methods for combating cucumber white rot is the constant change of planting sites. It is also important to burn all remaining plant particles after harvest. For 100% achievement of the effect, it is recommended to remove the various remaining parts of the plants simultaneously with the top layer of soil (2 or 3 cm). As soon as it became clear that the young stems began to rot, they must be removed immediately. It is also important to remove the soil layer along with them.
For cucumbers in greenhouses!
It is important to maintain optimal moisture and heat conditions in greenhouses. To prevent humidity from being too high in greenhouses, regular ventilation will help to avoid this.
Cucumbers love evening watering and warm water.
If white rot attacked the tissues of the cucumber, chalk, ash, crushed coal are used for effective sprinkling. Many gardeners do this: they smear the infected areas with a certain pink composition. To prepare it, you need to mix potassium permanganate, chalk and water.
If you can see that the areas are severely affected, they are cut out along with the healthy tissue that is nearby. Greenhouses and soil must be thoroughly disinfected at intervals.
Foliar dressing for cucumbers can be very helpful. To complete them, you need:
Foliar top dressing recipe for white rot
dilute 10 g of urea and 2 g of copper sulfate, 1 g of zinc sulfate in a 10 liter bucket of water.
Watering young cucumbers with 0.1% Planriz solution will be very useful during the growing season. It will not hurt to apply the "Trichodermin" agent, and also coat the cucumber stalks with an aqueous solution from "Rovral" and "Sumileks".
Symptoms of the disease
The fact that the plant is sick is evidenced by the brown color in which the root collar and roots of the cucumber are painted. The lower leaves begin to turn yellow, and all other leaves wither on summer days when there is a lot of sun. To acquire a painful appearance, flowers on infected plants gradually begin to dry out. Zelentsy will not continue their development.
By this time, the disease affects almost completely the entire root system. The roots acquire a dark brown hue. Their structure becomes loose. The outer layer of the stems perishes.
Diseased cucumbers quickly lose their healthy appearance and dry out. There is another symptom that rot destroys cucumbers with great force. This is that the stem is loosened at the bottom. It is easily separated from diseased brown-burgundy roots.
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If the soil is acidic in the pH range of 5-6, most of the pathogens quickly develop their activity. They develop well at temperatures of + 5- + 45 degrees. Each type of virus prefers a different temperature for activity. The pityum virus loves temperatures from 12 to 24 degrees. For the phytophthora virus, a temperature regime of more than 7 degrees is needed so that it exhibits maximum activity and forms harmful spores.
Soil moisture level is a factor that influences the level of development of almost all diseases. When a summer resident often and intensively watering cucumbers, in greenhouse conditions, soil moisture rises greatly, and the amount of oxygen needed by the roots for their normal life decreases. This is the reason why the root system becomes weak and vulnerable when the plant is attacked by phytopathogens.
With the disease "root rot" in cucumbers in greenhouses, the stem is milled
Ways to eliminate root rot
The fact that the leaves have become lethargic (as a result of the fact that the roots rot), the stratification of the stem near the base, and the gradual death of the root system are a manifestation of symptoms of a serious disease. Often, the reason for the lack of resistance to this pathogen is that the plants were planted in the soil in violation of certain rules.
How to prevent these troubles:
- Observe the principle of crop rotation (do not plant cucumbers in the same place for the next season).
- When the process of planting cucumber seedlings is carried out, they do not bury it to a strong depth. Enough 1 cm depth.
- The height from the leaves of the seedling to the soil should be at least 3 cm.
- Watering cucumbers is carried out only with warm water. You should try not to touch the plant itself.
- When feeding and mulching occurs, you need not to overdo it with the use of humus. The stem, in contact with the soil, needs oxygen, therefore, it must be provided with free access.
- The moisture level of the soil should be constantly monitored so that it does not exceed 85%. The soil temperature should be between +20 and +26 degrees.
- Salinization of the soil must not be allowed, since this factor greatly weakens the roots of the plant.
- It is advisable to choose chlorine-free fertilizers. It is worth using organic fertilizers that have been composted for at least 6 months.
- As soon as the summer resident noticed that the leaves of the cucumber began to fade, it means that the planting was not carried out as it should be done correctly. It is necessary to take a garden shovel, and carefully remove the earth from the cucumber stalks. It is important here not to touch the root that is shallow.
Cucumber feeding recipe
The resulting cracks are treated with the following composition: half a liter of water, 1 tsp. copper sulfate, 3 tbsp. wood crushed ash. Another option: fall asleep in the places of separation of ash, finely ground to a powdery state of activated carbon or chalk (dry).
If, after carrying out all the procedures, the bush does not begin to recover, it should be dug up and burned. The place where the diseased plant grew must be processed by pouring a mixture of copper sulfate into the pit.
To prepare containers with a nutrient solution, humus, turf and peat soil are used in a 1: 1: 1 ratio. It is advisable to use compost mixtures sterilized by biological means for at least 2 years. The cassette technology with mineral wool plugs gives a good result. It will avoid contamination of plants through the soil.
Laying the latest sterile mats is worth considering. These methods prevent plants from getting sick. If one and the same soil is used constantly, this will lead to the fact that various pathogenic organisms will accumulate in it.
If the root system of cucumbers rots, they can be saved if you still use this method. It will help when the cracks on the stems are small, and the lower leaves have just begun to fade.
Actions: using a sharp knife, cut off the lower, wilted leaves. Then they wait for the cut points to dry. The plant is removed from the support and placed on the ground. After this, the places where the leaves were cut are covered with earth.
Last step: pick up the plant and tie it to the support again. If such a procedure is carried out, young roots will appear on the part that was sprinkled with earth, and the plant will have a "second wind".
Video: Why do the leaves of cucumber seedlings turn yellow
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