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It is not for nothing that folk wisdom advises to count the harvest "on the table", and not on the garden bed. Even with the utmost attention, cultivated plants can lose all prospects for fruiting in a short time or, worse, die. Diseases of cucumbers in a greenhouse or open field are always easier to prevent, and therefore you need to know what a summer resident may face when growing a popular crop.
The main causes of the disease in cucumbers are improper care or lack of nutrition in the soil. Weakened, they easily become victims of pathogenic microorganisms, pose a threat to neighboring crops.
Cucumbers love warmth, and any changes in temperature, not excluding the usual daily drops, have a negative effect on plants. Watering with cold water is a kind of detrimental effect of cold on them.
Violation of crop rotation, contamination of the site with a variety of plant residues, connivance with pests are no less important causes of crop infection.
Diseases affecting your favorite culture are divided into three groups:
The most common disease that affects not only cucumbers. The causative agent hibernates on the stems and leaves of perennial crops growing nearby, the leaves left on the beds. Powdery mildew on cucumbers appears at the turn of spring and summer in brown spots with a whitish bloom - these are signs of the spread of mycelium through the leaves. Soon, the affected parts dry up completely, the lashes themselves develop poorly, the ovaries, if they appear, are already obviously infected.
The most favorable conditions for the development of the disease are damp cold weather, frequent fogs. In greenhouse conditions, factors contributing to the spread of the disease are a violation of the ventilation regime, watering with cold water.
Control methods:
This disease is more common than powdery mildew. Affected plants look like they have been burned by acid rain - with greenish-yellow spots on the leaves that dry out after a short time. Usually, the outbreak is observed from the beginning of August, when, due to large changes in day and night temperatures, morning dew is most abundant, and the rains become colder.
In greenhouse cultivation, the causes of damage are insufficient ventilation and lighting.
Means of struggle - Bordeaux liquid, copper sulfate, fungicides such as "Oxyhoma", "Cuprosata". Summer residents often opt for Rizoplan of biological origin.
After using copper-containing products, harvesting is carried out no earlier than two weeks later.
Signs of the disease - spots from light green or yellow to dark green, wrinkled leaves. As the disease progresses, the plant gradually dries up and dies.The field mosaic virus usually spreads aphids, it does not exist on the seeds. The virus often infects seedlings if the nutrient medium has been infected.
No cure has been found yet, so the only protective measure is pest and weed control, weeding and treatment with Aktara and Aktellik insecticides.
Viral infection is transmitted through infected seeds, spread by pests. It manifests itself as shriveled leaves, covered with spots, colored shades of green. Fruits are tied badly, strongly bent.
First of all, the cucumbers themselves are striking - irregularly shaped olive-colored spots appear on them, similar to ulcers. In greenhouse conditions, two weeks are enough for the virus to completely destroy the crop.
There are several reasons for the defeat - a sharp cold snap, cold water, drafts.
Having found signs of the disease, they stop watering, dry the plants. If the temperature is low, use a light shelter. You can cope with defeat by spraying cucumber lashes with Bordeaux liquid.
A disease of viral and fungal origin develops imperceptibly even for an attentive summer resident. Primarily affects the root system of cucumbers. In this case, the plant even manages to set fruits.
Signs of defeat:
There are several reasons for the disease:
With a successful combination of circumstances, when the disease was recognized at an early stage, the following measures are taken:
If possible, the lower part of the lash is laid on the ground in a ring and covered to stimulate the development of new roots.
However, these measures will not work if the roots are so affected that they have turned into dust or mucus. In this case, the plant is dug up and burned. The place where it grew is spilled with a solution of copper sulfate.
The disease usually develops due to tightness in the garden, as well as due to overflow or cold water. It manifests itself as a gray, moist bloom on the stems, usually in their lower part, and on the leaf stalks.
The disease is treated with simple disinfecting substances - ash, potassium permanganate, copper sulfate. They add ordinary school chalk, grind it into a gruel with a small amount of water and apply it to the affected areas previously cleaned of plaque.
The main reason is the ingress of cold water on the stems and leaves of cucumbers. White flocculent spots appear on them, and then multiple black dots. The affected parts begin to rot.
When a disease is detected, the affected leaves and shoots are cut off, treated with the preparations "HOM", "Fitosporin".
Fungal disease, manifested by spots of brown-rusty (copper) color on fruits and leaves. The leaves gradually dry out completely, the cucumbers become unusable. The disease is treated by treatment with colloidal sulfur, Bordeaux liquid, drugs "Quadris", "HOM".
Disease of greenhouse and ground cucumbers of any age - from seedlings to an adult plant. The fungus is most active precisely during the period of mass fruiting, rendering the entire crop unusable.
Disease manifestations:
The disease noticed at an early stage can be treated with a mixture of copper sulfate and chalk 1: 1 with the addition of water. The paste is coated on the affected areas of the stems.
The correct choice of a variety that is resistant to diseases characteristic of the area (site) helps to reduce the risks of diseases of cucumbers.
The causative agent of the disease is active at elevated levels of humidity and temperature. Its insidiousness is that it manifests itself when the plant is significantly affected - oily spots of brown color appear on the leaves and stems, which then dry out and fall out, leaving only veins of the leaf plate.
A characteristic feature is the drooping top of a cucumber bush during the day, during the night it returns to normal. As the mycelium spreads inside the plant, it stops growing and dries out completely.
For treatment, "Previkur" is used.
Signs of late blight on cucumbers:
The causes of the onset of the disease are common to all fungal infections - high humidity combined with poor ventilation, temperature drops.
When the first signs of phytophthora are found, cucumbers are treated with Bordeaux liquid:
Instead of "Bordeaux" you can use "HOM", "Oxyhom", "Barrier", etc.
The cause of the disease is a dense planting of cucumbers, excessive watering. The disease affects plants at any stage of development, from seedlings to adults. In the seedlings, the area of the root collar turns yellow, orange-colored spots appear on the cotyledon leaves. The reaction of adult plants - dark spots on the leaves, ulcers on the stems, depressions on the fruits.
To combat fungicides are used - chemical ("Quadris", "Ridomil Gold") or biological ("Trichodermin", "Baktofit").
Chlorosis occurs when there is a lack of nutrients, as a secondary disease after a fungal infection, under improper growing conditions.
The treatment is carried out by spraying on the leaf with fertilizers-chelates containing vital micro- and macroelements in a form easily assimilated by plants.
Summer residents who do not want to use chemistry in the areas use home remedies to treat cucumbers.
Preventive measures, if carried out in a timely manner, do not take much time.
Widespread among summer residents was the drug "Cucumber Rescuer", which combines the properties of an insecticide, acaricide, fungicide, growth stimulator. It is easy to use, has good protective and stimulating properties, and works in greenhouse and open field conditions.
Any disease that affects cucumbers requires immediate treatment. However, timely prevention and proper planting care will relieve the summer resident of additional worries aimed at treating plants and unpleasant emotions.
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