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Cucumbers diseases: What problems are typical in vegetables and by what features you can recognize them.

Of course, if your cucumbers have diseases, it is extremely annoying. So much time and effort you have put into caring for them, and now there is still a risk that your harvest will go down the drain. But do not despair right away, because in most cases you can still save the fruit if you act quickly and correctly. We have compiled some typical cucumber diseases so that you can recognize and treat them.

Wilt diseases and fungal diseases

Cucumber diseases pictures - vegetables can be affected by bacteria, viruses and fungi

As the name suggests, these are cucumber diseases that cause certain parts of the plant to wilt. Dieс can be the result of various causes, which we would like to list for you once below.

Cucumber wilt is a fungal disease.

Cucumber diseases and pests - wilt diseases with symptoms during the day.

It is the so-called Fusarium fungus that affects the plant and causes it to wilt leaves. You first notice this during the day. Your cucumber plant is drooping leaves even though you have watered it appropriately? Then this may be the reason. During the night, again, the leaves do not seem to lack anything. Then the cucumber plant begins to die, first the leaves turn yellow and dry up after a relatively short time, while the roots turn brown and rot. Sometimes the fungus can be detected. It usually appears on the stem and has a pink color.

Typical diseases of cucumbers – black root rot.

Black root rot causes the roots to rot and the cucumber plant to die

Again, the name already indicates what it is. The fungus mainly affects the roots, which due to this turn black and rot. Nevertheless, new roots develop, but the lower leaves die. Yellow leaves in cucumbers can therefore be an indication of this, if the yellowing occurs only in the lowest pairs of leaves.

Powdery mildew and downy mildew

Both powdery mildew and downy mildew on cucumber are not uncommon and are caused by different conditions. Typically, the cucumber plant gets white leaves when powdery mildew is involved (even with gray mold), while with downy mildew, the cucumber leaves get yellow spots. To learn how to control powdery mildew on cucumbers, read this article .

Cucumber diseases - cucumber mosaic virus causing yellow green spots on leaves


Diseases of cucumbers – other possible fungal diseases

  • Anthracnose – causes fruit spoilage and is characterized by red mold spores that cause fruit to dry, become watery and blotchy (dark gray and brown), and then also cause the plant to die.
  • Gray mold – thick, gray coating on stems, leaves, and fruit bases.
  • Sclerotinia stem rot – the fungus develops at the base of the stem as well as on the fruit
  • Stem base rot – plants wilt; stems become rotten; the greenish fungus then rots the plant
  • Verticillium wilt – lower leaves become limp and brown, which, like cucumber wilt, changes at night

Cucumber diseases - gray mold forms a thick gray coating on the leaves

Viral diseases of cucumber plants

While fungal diseases usually show coatings and spores, viruses do not cause such signs. However, they are extremely dangerous to plants because they can kill them. The following two cucumber diseases are virus-related and sometimes occur.

The plant gets yellow leaves – cucumber leaf spot virus.

Cucumber diseases yellow leaves due to cucumber leaf virus


The disease can be seen on the leaves, and more precisely on the young leaves, while the fruits themselves do not reveal any signs of disease. They get spots of greenish-yellow color, which first appear on the edge of the leaf and then spread. In addition, there is a brown spot in the middle of the leaf, as well as blister-like appearances around it. All you can do for this disease is to dispose of the plant as soon as possible to avoid spreading it to other cucumber plants. There are no effective remedies for this virus.

Cucumber diseases – The cucumber mosaic virus.

Chances are not much better with this viral disease transmitted by aphids, but you can at least prevent transmission by always controlling aphids immediately. The leaves and fruits get spots of light green color, somewhat resembling mosaic. The growth of the plant is also affected: new leaves are deformed and the plant suddenly stops sprouting. If you do not act, the cucumber plant will wilt or die. Dispose of it as soon as you have identified the disease.

Bacteria can make cucumber plants sick

How to recognize and treat cucumber diseases

Yes, bacteria can also infect plants and in most cases this causes the fruit to rot and become inedible. Your harvest is thus gone. What bacterial diseases are typical cucumber diseases?

Cucumber diseases – Bacterial soft rot

These bacteria land on the plant through water splashes, where they can infect the plant through damaged areas. The flowers or, at a later stage, the fruits are affected. They become muddy and rot, which can be quickly detected by their odor. It does not matter in which growth stage the cucumber fruit is. Immediately dispose of the infested fruit, because apart from the fact that they are no longer edible, they can infect other plants. There are no sprays for cucumbers against this disease.

Angular leaf spot disease

Why cucumbers turn yellow - downy mildew causes spots on the leaves

Cucumber leaves turn yellow and what is most noticeable is the glazed appearance. The developed angular leaf spots grow over time and the spots on the cucumber leaves turn brown and they dry up. The fruits are also affected, which they can tell by the squishy spots with a white dot in the center and a dark border. Also check the undersides of the leaves. If you find a slimy coating there, you can assume that it is just this bacterial disease.

As a preventive measure, you can pay attention to high-quality and healthy seeds, as well as choose varieties that are resistant. In case of infestation, dispose of the plant. Keep in mind that these bacteria can easily overwinter in the soil. Therefore, this should not be planted in the next three years in any case.