Basically, cucumber diseases progress in the second half of summer, when cold early morning dew appears. But some infections can be annoying at the beginning of the growing season. In many ways, the success of plantation treatment depends on how quickly you detect the disease. Therefore, it is necessary to frequently inspect the plants and take action when the first suspicious symptoms appear. For this enemy you need to know by sight and be aware of what diseases of cucumbers exist. It:
- powdery mildew;
- peronosporosis - downy mildew;
- white rot - sclerotinia;
- cladosporiosis - brown olive spot;
- root rot;
- gray rot;
- anthracnose.
Disease # 1: Powdery Mildew
It begins with the appearance of white spots on the leaves. These parts of the plant seem to be sprinkled with flour. That is why the disease got its name. Along with this symptom, sometimes there is a reddish bloom on the leaves. The affected parts turn yellow and dry, due to which fruiting stops prematurely.
This is facilitated by fungi that remain on last year's plants. Cool and cloudy weather encourages the onset and development of the disease. The suspension of this process is facilitated by the air temperature, if it is above + 20 ° C.
Here are the main conditions for the occurrence of powdery mildew:
- cool cloudy weather;
- application of large doses of nitrogen fertilizers;
- non-compliance with sanitary standards (there is no soil disinfection, last year's plant residues have not been disposed of);
- irregular and insufficient watering.
Powdery mildew treatment and prevention
After the first signs of the disease appear, the plants need to be sprayed with one of the proposed drugs:
- "Hom";
- "Topaz";
- Colloidal sulfur.
For the first method, you need to dilute 20 g of Hom powder in 5 liters of water and, after collecting the cucumbers, spray the lashes on the sheet with this solution. This amount of the finished product is enough to process 50 sq. m. area.
To prepare the next solution in 5 liters of water add 1 ml of the drug "Topaz". This liquid can be used not only for medicinal, but also for prophylactic purposes.
Good results are obtained by weekly spraying of a cucumber plantation with a 20% solution of colloidal sulfur. You can treat plants with a 4% solution of ferrous sulfate or 0.5% solution of soda ash with soap for sticking, or 1% solution of Bordeaux liquid. Spraying should be done in dry, calm weather.
If you do not want to use chemicals, you can use folk remedies. You will read about them at the end of the article, so not only powdery mildew, but other diseases of cucumbers can be prevented if you start to process the plants at the very beginning of their appearance, and better when the 3-4th real leaf appears on the bush.
To prevent powdery mildew and a number of other diseases of cucumbers, you must:
- observance of crop rotation, sow cucumbers in this place no earlier than 4 years later;
- timely cleaning followed by burning plant residues, disinfection of the greenhouse after harvest;
- cultivation of hybrids resistant to powdery mildew and other diseases;
- timely watering the plantation with warm water;
- when cold nights come, cover the plants with foil, non-woven fabric or close the greenhouse from evening to morning.
Disease # 2: Downy mildew
Its second name is penorosporosis. It also begins with the appearance of spots on the leaves, but light yellow. They soon enlarge and cause the leaves to dry out. This is facilitated by a fungus, the appearance of which is promoted by high humidity and watering plants with cold water.
To prevent downy mildew, you must:
- observe crop rotation;
- water the plants only with warm water, and with the onset of cold nights do it in the morning;
- do not thicken crops;
- harvest on time.
Treatment measures:
- When the first signs of this disease appear, reduce watering and feeding;
- Cut off affected leaves by disinfecting the tool;
- Treat the plantation with folk remedies or fungicides;
- Cover open ground plants with foil overnight.
Here are some medications against powdery mildew to help cope with it:
- Oxyhom;
- "VDG";
- "Kuproksat";
- Ridomil;
- Ordan;
- "Bordeaux mixture" and others.
You can dilute 100 g of fresh lime and copper sulfate in 10 liters of warm water and process the plants.
Disease # 3: White rot - sclerotinia
It appears as white patches that darken over time. In this case, not only stems and leaves, but also fruits can be affected. Plaque covering parts of the plant makes them slippery and decaying.
If the greenhouse has poor ventilation, thickened plantings, low daily temperature, then the disease quickly spreads further. The disease is also dangerous because it can have a latent form. In appearance, the fruits affected by sclerotinia seem healthy, but in fact they are unsuitable for human consumption, since they are not stored - they quickly rot and even decompose when canned.
If you notice that the plant is sick, cut off all its affected parts, treat the cuts with crushed charcoal or lime. Give the cucumbers a top dressing, diluting 1 g of copper sulfate and zinc sulfate and 5 g of urea in 5 liters of warm water.
Disease # 4: Cladosporium - Brown Olive Spot
Visually, it looks like this: spots and sores of olive or green-brownish color appear on the leaves, stems and fruits. Most often, the disease affects weakened plants, during the care of which mistakes were made. Cladosporium fungus spreads as a result of rain, wind, and water. Low air temperatures and drafts also contribute to its appearance.
To defeat Brown Olive Spot, you must:
- 5-6 days do not water the cucumbers;
- in cool times, increase the temperature by closing the greenhouse doors or covering the plantings with foil;
- air the plants on warm days;
- to treat with the drug "Oxyhom" (for 10 liters of water 20 g of powder) or 1% solution of Bordeaux liquid.
These agents are sprayed in the morning in warm weather, and after 5-6 days, the treatment is repeated. After spraying, it is necessary to ventilate the planting.
Disease # 5: Root Rot
It can make itself felt if you water the cucumbers with cold water, due to the increased air temperature in the greenhouse with high humidity. Both over- and under-watering can lead to this.
You can determine that cucumbers have root rot if the leaves dry out, wither and gradually dry out, and the root of the plant is reddish and rotten.
To prevent the appearance of root rot, cucumbers should be treated with a solution of the "Previkur" preparation every 2 weeks.
If the plant is severely affected, it is dug up. If it is insignificant, you can cut off the affected part and sprinkle it with wood ash powder or sulfur.
You can revive the lash if you remove the leaves from its lower part, put the stem on the ground and sprinkle it with fertile soil on top. Watering should be done carefully from a watering can. Then soon new roots will form on this part of the stem, and the plant will be saved.
Disease # 6: Gray Rot
It covers the stems, leaves and even flowers of the cucumber with brown, watery spots, on which there is a smoky gray bloom. If the fungus of gray rot has penetrated into the flower, then the cucumber embryo will quickly rot. If he settled in an internode, then a part of the plant, above this place, will die.
Most often, the development and spread of this disease is facilitated by wet, damp weather, poorly harvested remains of last year's plants.
Treatment for gray mold consists of:
- pruning infected leaves;
- compliance with the optimum air humidity - not increased;
- dusting the affected stems and leaves with copper-chalk powder;
- coating the stems with a mixture of "CMC" and "Trichodermina", and for prophylaxis - spraying with a suspension of "Trichodermina";
- lubricating the affected parts of the plant with a mixture of the preparation "Rovral" and chalk, taken in the same proportion with the addition of a small amount of water to obtain a viscous texture.
Disease # 7: Anthracnose
It is most annoying for cucumber plants in plastic greenhouses. At the same time, on the affected parts of the cucumber, spores of the fungus develop in the form of pale pink pads, which are numerous and arranged in circles or almost merge.
Fungal spores can be found in seeds that were collected from infected fruits, in plant debris.
Prevention of anthracnose is reduced to deep digging of the soil, pre-sowing treatment of seeds with special preparations, for example, "Tiram". For treatment, sulfur preparations, 1% solution of Bordeaux mixture, copper oxychloride with a concentration of 0.3%, preparations "SK", "Quadris" are used.
Folk remedies for combating diseases of cucumbers
Of course, you need to be very careful with chemicals. It is best to apply them before fruiting. If the disease manifests itself later, first collect all the fruits, then process the plants and eat cucumbers no earlier than 5-7 days after that, after washing them properly.
To prevent powdery mildew in 1 liter of milk, dilute 20 grams of grated laundry soap, 20 drops of iodine. Spray the cucumber vines every 10 days.
Chop 25 g of garlic in a garlic, dilute the gruel in 500 ml of water, close the lid, leave for 24 hours. Then, dilute this solution with 4.5 liters of water, spray the plants. This infusion is especially effective against downy mildew.
Ash, in addition to fighting diseases, contributes to plant nutrition. Pour 3 tablespoons into 2 liters of warm water. l. ash, leave for 2 days, strain, add 10 g of laundry soap, spray the plants.
For more information on diseases of cucumbers, see this video:
