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Yellow spots on cucumber leaves: how to treat
Yellow spots on cucumber leaves: how to treat

Video: Yellow spots on cucumber leaves: how to treat

Video: Yellow spots on cucumber leaves: how to treat
Video: Yellow Marks on Cucumbers Leaves, Insect Damage & Treatment: Neem Oil - TRG 2014 2024, March
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Gardeners are often faced with a situation when cucumber leaves dry out, wither, turn yellow, or strange spots appear on them. There are several reasons why this happens. So, yellow spots on the leaves of cucumbers can be the result of both improper care and disease.

Diseases

Dangerous diseases arising from the cultivation of cucumbers include downy mildew and powdery mildew, bacterial angular spot, anthracnose and cladosporium. Currently on the market you can buy varieties of cucumbers that are resistant to some of the above pathologies.

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Downy mildew

The most dangerous disease in cucumbers is downy mildew (P. cubensis). Symptoms of the disease are visible on the leaves - initially they are olive green, then lighten to white or yellow. With high humidity, areas similar to bumps are formed on the underside of the sheet plate, as in the photo. The spots turn brown as the disease progresses. Infected plants die.

The spores of the fungus can be spread by wind over long distances. The development of the disease is favored by cool and humid conditions (temperature 10-16 ° C), prolonged night fog and sunny days with a temperature of 23-25 ° C.

Even with resistant varieties, the ability to withstand downy mildew is negligible.

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For protection, contact measures such as fungicide treatments can be used. When the first spots appear, it is recommended to spray them with deep-acting agents or Planriz biological product.

You can also use the means of contact-system action. The first treatment should be carried out in the phase of 2-3 true leaves, the second before flowering, and the last after harvesting.

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Angular spotting of cucumbers

Typical symptoms of bacterial angular spotting in cucumbers appear on the leaves as small, light, angular spots. In conditions of high humidity, mucous drops are observed on the underside of the leaf plate. Inside the spots, leaf tissue dies and crumbles.

The disease is provoked by the bacterium Pseudomonas syringae, which feeds on infected plant debris. The disease is promoted by high humidity. The bacterium is spread by wind and water (during spraying), as well as in the process of leaving or collecting fruits. Pollinating insects can also spread disease to nearby plants.

Protection against bacterial corner spot should be initiated at the first sign of onset, when weather conditions are favorable for bacterial growth. For this, you can use contact drugs.

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Anthracnose

The causative agent is the mushroom Colletotrichum orbiculare. Infected plants develop watery light green spots that gradually turn yellow. Dead tissue crumbles, and holes form on the leaves. The mushroom hibernates on plant debris. The increased air humidity contributes to the spread of the disease.

The preparations "Fitosporin" and "Topaz" are intended to protect cucumbers from anthracnose. The disease is also eliminated by spraying with Bordeaux liquid.

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Powdery mildew

As a result of powdery mildew damage, a characteristic light trace can be observed on the upper side of the leaves, which gradually covers the leaves and shoots. In a severe form of the disease, the plants die.

The mushroom hibernates mainly on plant debris. The development of the disease is facilitated by the intensive growth of plants with limited availability of light and periodic wetting of the leaves. For preventive purposes or when the first symptoms of the disease appear, you can use both special drugs and folk remedies.

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Cucumber mosaic

Mosaic in cucumbers is a viral disease. Also characteristic spots appear on young leaves, which are then deformed and wrinkled.

Since the disease is easily transmitted from one plant to another during care, it is always worth remembering to thoroughly disinfect all garden equipment and tools. It is also worth taking care of acquiring persistent and strong varieties. And it is imperative to fight aphids when they appear, since these pests often provoke a mosaic.

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Cladosporium

The disease is also called scab. The fungus Cladosporium cucumerinum is responsible for the appearance of yellow spots in this case. Yellow-brown spots are visible on the leaves, and small (necrotic) gray-olive or yellow spots appear on the fruits. Cucumbers are unsuitable for consumption - they quickly deform and rot.

This fungus can survive in plant debris and seed for 2-3 years. For prophylaxis or when the first symptoms of cladosporium appear, it is necessary to spray.

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Care errors

They can also be the reason why yellow spots appear on the leaves of cucumbers. These are common actions that many gardeners do unknowingly. Such mistakes are not uncommon among beginners.

Insufficient lighting

Insufficient light is the main reason if the leaves at the base of the cucumber bushes turn yellow. Most likely, the crops were planted too close to each other. In this situation, it remains only to periodically rid the plants of yellow leaves.

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Improper watering

Cucumbers love water. But excess moisture can create the same effect as dry and yellow foliage. Cucumbers should be watered 3 times a week on warm days and every day in hot weather. It is recommended to use a limited amount of water to provide moisture to the roots, but avoid excess water.

You can use soil mulch to prevent water from evaporating if you can't water your crops on time.

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Lack of fertilizer

If the edges of the leaves dry out, potassium and magnesium are needed. If the yellow leaves have green blotches and lines, then the plant needs manganese and iron. If the upper part of the leaf turns yellow, copper must be added to the soil.

You need to sprinkle the wood ash directly on the foliage, and the herbal decoction can be used as a liquid fertilizer. Do not forget about spraying and preventive feeding:

  1. Recipe number 1: add 20 g of laundry soap, 1 liter of milk and 30 drops of iodine to 10 liters of water. Spray the bushes with this mixture until the first leaves appear, repeat 3 times a month.
  2. Recipe number 2: soak a loaf of bread in 10 liters of water, then crumble. Add iodine. In the summer, spray the cucumbers twice a month.
  3. Recipe number 3: add 1 tablespoon of baking soda to a bucket of water. It is necessary to water the bushes at the beginning of summer.
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Age

Sometimes, after the formation of fruits, the leaves of cucumbers turn yellow. Experienced growers know what to do. Prevention is the most effective remedy. It is necessary to follow the rules of crop rotation.

Cucumbers should be grown on a new site every year. You cannot plant a pumpkin next to it, as it is susceptible to the same pests as cucumbers.

Pests

Whitefly and spider mites feed on the juice of cucumber leaves. They dry and turn yellow. The answer to the question of how to get rid of them is simple - you can prepare a special solution. To do this, insist chopped onion and garlic husks in water, after which the affected crops are sprayed.

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Outcomes

  1. Cucumbers are often affected by various diseases and pests. Fortunately, they can be dealt with using safe, sustainable practices.
  2. Fungicidal preparations will help to cope with pathogens that lead to the formation of yellow spots on the leaves.
  3. But the cause of the yellowing of the foliage in cucumbers is not always the disease. Sometimes this is facilitated by improper accommodation and care.

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