Why do the leaves of cucumber seedlings turn yellow
To get the most out of vegetables, you need to carefully consider all of their requirements. When growing plants, difficulties arise not only for novice farmers, but also for experienced farmers. Why do the leaves of seedlings turn yellow in cucumbers? We will analyze in detail the culprits of the problem and tell you about ways to deal with them.
Causes of the appearance of yellow leaves on cucumbers
Improper care
One of the most common factors for plate yellowing is improper cultivation. A capricious vegetable instantly reacts to any changes, changing the color and turgor of the greenery. In order to prevent the death of seedlings, you need to know the most common mistakes.
Nutrients
The imbalance of trace elements in the soil always negatively affects the appearance of plants. For an experienced farmer, foliage transformation will be the first bells for the beginning of problems. Cucumber seedlings need root and foliar dressing with preparations with:
- potassium;
- nitrogen;
- manganese;
- gray;
- calcium.
With a deficiency of the first two substances, the state of the greenery deteriorates noticeably. An excess of elements is as dangerous as a deficiency, therefore it is not advised to overfeed the seedlings. Chemicals can burn the roots, causing the foliage to change.
Irrigation
If the seedlings turn yellow in cucumbers, and the plates turn white and curl, this is a sign of improper watering. The plant is extremely demanding on moisture, therefore it reacts negatively with any deviations from the rules. Knowing its physiological characteristics, you can quickly determine the cause.
In dry soil, it is difficult for a culture to absorb nutrients, which leads to starvation. Excessive irrigation leads to acidification of the earth, which becomes the cause of fungal diseases. If the leaves of the cucumber turn yellow or the edges brighten, this is a consequence of watering with cold water.
Diseases
In the conditions of the domestic climate, it is customary to cultivate zelentsy by the seedling method. The technology saves time and makes it possible to get the first harvest a couple of weeks earlier. For any violation of the rules of cultivation, plants are attacked by diseases.
Powdery mildew
The fungal disease begins from the edges of the leaf, after which it gradually captures the entire plate and passes to the stem. Mealy white or yellow spots are signs of the disease. If left untreated, green tissues dry out and die off.
The pathogen hibernates without problems in organic residues, after which it infects the plants. Most often occurs in cloudy weather or at temperatures below 18 ° C. An excess of nitrogen fertilizers in the soil with insufficient watering also activates the disease.
Downy mildew
Why do cucumber seedlings turn yellow? The fungus quickly infects the leaves, after which it spreads throughout the tops.Single light spots appear on the upper side of the plate, which gradually acquire a brown color. The greenery dries up, crumbles into small pieces and infects other plants.
The pathogen hibernates without problems in plant debris, and with the onset of favorable conditions begins to actively grow. If nothing is done, in warm, humid weather, the destruction of plantings of cucumbers takes place in a short time. From the onset of the disease to death, it takes 2 to 7 days. With the onset of heat, the disease subsides, but the pathogen remains alive.
Mosaic
The viral disease manifests itself as white or yellow spots on the leaves. The affected plates wrinkle over time and acquire a bright color. Due to the destruction of greenery, the plant cannot develop normally, therefore it often dies.
The virus causes a temperature mismatch
The disease spreads with high humidity, and one of the activation factors is the wrong temperature regime. If the soil does not warm up above 16 ° C, the pathogen spreads quickly. Among the reasons for the emergence of the virus are:
- insects;
- weeds;
- infected inventory;
- non-compliance with the rules of crop rotation.
Root rot
If the seedlings of cucumbers have turned yellow, this indicates a fungal disease. The first signs will be a change in the color of the plates of the lower tier, after which wilting occurs and the appearance of cracks on the stem at the root. The greenery dries up and the underground parts become rotten and rusty.
Most often, the disease occurs due to a sharp change in soil temperature and when irrigated with cold water. Increased humidity during growing crops also becomes the cause of the activation of the pathogen. Thickened planting of seedlings and contaminated soil are the culprits for the destruction of young plants.
Pests
If the leaves turn yellow on the seedlings of cucumbers, it is recommended to carefully examine the plate from all sides. Parasitic insects feel great both in the open field and on the windowsill. Farmers are not always able to quickly identify the culprit, which, when neglected, leads to the death of plantings.
Aphid
A small pest is capable of causing damage in a short time. It is highly fertile and resistant to poisons, so it is difficult to destroy it the first time. The signs of an insect are sticky droplets on the plates, next to which ants gather. The plant is sick and withers, the greens turn yellow and curl.
Aphids can be found on the underside of foliage. A small light grayish-white creature has a body length of no more than 2 mm. The parasite prefers to accumulate around growth points and on shoots.
Spider mite
Small arachnid insect that feeds on the contents of plant cells. With a large distribution, the culture is infected with gray rot. Liana loses its susceptibility to external factors, which is why it easily dies.
At the initial stage, white dots appear on the greenery, which gradually cover the entire plate. A thin cobweb envelops the bush, especially noticeable at the point of growth. Pests move quickly and infect neighboring crops. The attack is caused by high temperature and dry air.
Greenhouse whitefly
If the edges of the leaves dry on the seedlings of cucumbers, and the plates are covered with indistinct light spots, these are signs of a small white-winged parasite. In different parts of the plant, you can find sticky secretions, the greens are deformed and disappear. The cucumber pest draws juices from the culture, so the infected plantings die within 2 days.
The insect is dangerous because, in addition to sucking the nutrient fluid from the greenery, it creates conditions for the occurrence of diseases. The sooty fungus prefers to settle in the droplets of vital activity. Such specimens are no longer amenable to treatment, they are uprooted and burned.
How to fight
You need to start treatment as soon as possible
If the leaves of cucumbers or seedlings turn yellow and dry, immediate measures must be taken. Often problems arise at the window or after planting in a permanent place of growth. The sooner the cause is eliminated, the easier it is for the bushes to get rid of stress.
With diseases
What to do if yellowing of greens in cucumber appears due to fungal diseases? The causative agents of powdery mildew or root rot do not like medicinal preparations. Treatment of foliage and soil with Bordeaux liquid is the most effective method of control. Sometimes, two waterings with "Previkur" are enough with an interval of 2 weeks.
As soon as yellowing becomes noticeable after disembarkation, emergency measures must be taken. Cucumbers are irrigated with Topaz, alternating the procedure with colloidal sulfur. The seedlings are very sensitive to chemicals, so the product should be dosed carefully. For downy mildew it is better to use "Fitosporin".
If the leaves on the seedlings of cucumbers have turned yellow mosaic, there is no panacea for the virus. All saplings affected by the disease must be pulled out and burned, and the site must be treated with copper sulfate. To avoid a dangerous disease, it is advised to choose varieties with immunity.
With insects
When fighting aphids, folk measures are used. It is necessary to pour boiling water over 0.5 kg of chamomile flowers, leave for 12 hours, then strain, add liquid soap and pour into a bucket of water. The resulting liquid is sprayed on the bushes every 4 days.
In advanced cases, chemistry is used from spider web. It is not as safe as herbs, but it copes with the problem much more effectively. For the destruction of insects on cucumber greens, it is advised to use acaricides ("Akarin", "Fitoverm", "Apollo"). When a pest enters the body, they quickly destroy the population. It is recommended to repeat the procedure after 7 days.
With a slight defeat, preference is given to folk remedies. The spider mite is killed by some plants. Half a bucket of dry marigolds is poured with warm water, insisted for 48 hours, filtered. 50 g of laundry soap shavings are added to the resulting composition. The bushes are sprayed in the evenings every 2-3 days.
In a neglected state, only chemistry will help from a greenhouse whitefly. There are special drugs (Aktara, Pyrmethrin, Aktellik) that destroy parasites. In order for the active substances to adhere better to the foliage, it is advised to add a little liquid soap to the spray solution.
With care mistakes
Nutrient deficiencies are best treated with regular application of complex mineral remedies. When growing seedlings, fertilization begins on the 10th day after pecking the seeds, after which the procedure can be carried out every 2 weeks. After transplanting to a permanent place of growth, they are fed by the root method and along the leaf.
If the edges of the plate have turned yellow on the cucumber due to improper irrigation, it is worth revising the whole procedure. The land between waterings should have time to dry, but not allow many days of thirst. The manipulation water is always heated to 20 ° C. To do this, it is enough to pour a liter of boiling water into a watering can or heat it in the sun. When growing seedlings on a windowsill, it is advised to avoid sudden temperature changes.
Prophylaxis
To avoid changes in the greenery, you need to secure the seedlings in advance from possible problems. Before planting vegetables on the site, it is necessary to do preventive soil treatments with copper-containing preparations and remove organic residues. Before agricultural work, the tool is always disinfected.
Cucumbers are a thermophilic crop, the temperature in the room where the seedlings are grown should not be lower than 25-28 ° C.
You cannot plant cucumbers for several years in a row in one place. Species diseases are concentrated in the ground, which are difficult to get rid of in safe ways. It is better to give the site a couple of years to relax, and place your favorite culture in another part of the garden.
When growing vegetables, problems with herbs regularly arise.If the leaves of cucumber seedlings turn yellow, it is worth proceeding with immediate localization. These guidelines present the culprits of transformation and how to effectively deal with them.