Anyone who grows cucumbers must expect that diseases and pests can spread from time to time. Learn how to recognize and fight them here.
Cucumbers originally come from subtropical regions, so they need a lot of warmth in our gardens. Should the summer turn out cool, then the plants can become susceptible to various diseases.
That's why many hobby gardeners prefer to grow them in a warmer greenhouse. (Reading tip: Planting cucumbers in a greenhouse - tips for cultivation) But not only the climate plays a decisive role, there are also various other causes that can cause diseases and pests.
Today we are introducing the most important cucumber diseases, explaining the damage they can cause and giving tips on how to combat them.
The 8 most common cucumber diseases
1. Powdery mildew
Recognize
Powdery mildew is a fungal disease that is unfortunately widespread in gardens, and cucumbers in the greenhouse are not spared either, two different ones are responsible for this pathogen. First, the damage develops on the surface of the leaves, the fungi literally suck the nutrients out of them. The white spots get bigger and merge together until the entire surface of the leaf is covered with a white coating. The leaves dry out, turn brown, and then die.
If the infestation is very severe, the fungus can also be found on the stems. Wind and drafts ensure that these fungal spores spread. The pathogens can also survive on plant remains. The big difference to other types of mushrooms is that powdery mildew thrives particularly well in dry and warm weather.
Fight
It is better not to fight the disease with chemical agents, as this also makes the cucumbers inedible. You can try home remedies to combat it. Add 100ml of milk to 900ml of water and spray the plants with it. Garlic cloves can also be a way to fight powdery mildew. To do this, chop three cloves of garlic and pour 500 ml of boiling water over them. After cooling, the garlic cloves are fished out and the cucumber plantssprinkled with the broth.
Prevention
To minimize the risk of powdery mildew, it is best to only buy resistant varieties.
Recognize
Downy mildew mainly attacks cucumbers or pickled cucumbers that are grown in the garden or in a greenhouse. You can recognize it by the light green to yellow-brown spots on the leaves of the plants, which are particularly evident in the summer months. If you turn the leaves over, you will see a grey-purple coating on the underside.
Fight
Downy mildew can spread extremely quickly, and the affected plants gradually turn yellow and die. To prevent downy mildew from spreading to all plants, you should immediately destroy infested plant remains.
Prevention
In order to prevent the disease, you should pay attention to resistant varieties when buying. You should avoid high humidity in the greenhouse and therefore ventilate it regularly.
3. gray horse
Recognition
Gray mold is also caused by a fungus that can survive on fallen leaves. The mold can spread through the flight of spores, especially if the humidity is quite high for a long time or if dew forms on the plants at night. You will then see a grey, velvety coating on the leaves, the stems and the bases of the fruits.
Control/Prevent
To prevent the fungus you should only water the soil, never the leaves and stems of cucumber plants. In greenhouses it is important that you ventilate regularly. Immediately dispose of infested plant parts in the residual waste.
Avoid watering the plants in the evening. The resulting moisture cannot escape properly during the night. You should also avoid plant strengtheners, as they significantly affect the taste of the cucumber. It is better to provide a portion of fertilizer regularly to strengthen the plant. You can find tips on this in the article Fertilizing cucumbers - How to increase your yield. When planting cucumbers, make sure that there is enough space between the individual plants.
4. The Sclerotinia WiltRecognize
There are some wilts that can occur in cucumbers. One of them is the Sclerotinia wilt. This mainly affects cucumbers in the greenhouse. Peppers, tomatoes and lettuce are also affected. Infection can be through spores. The fungus appears as white, woollyCoating on the stems of the cucumber plants, which then begin to rot.
Although the cucumbers are sufficiently watered, they wilt. Later, the fruits are also covered with a fluffy coating. Shortly thereafter you will see small, black globules in it.
Control/Prevent
Sclerotinia wilt is not that easy to control, so it is important that it does not get there in the first place. Prevent the fungus by avoiding high humidity in particular, as it spreads particularly quickly here. Make sure the leaves are not wet for a long time. So never water in the evening and always only water the soil.
5. Other wilting in cucumber plants
Recognize
There are several fungi that can cause plants to wilt even if you water them properly. As soon as the plant dies above ground, the roots also begin to rot. You can see the fungal network on the stems, and the leaves are also turning brown and dying. The fungi can also survive in the soil for many years and attach themselves to plant debris, leading to new infections.
Prevent
To prevent wilting, you can graft young cucumber plants on the fig leaf gourd to strengthen them. (Reading tip: grafting cucumbers - this is how it's done) As soon as a plant has wilted, you should remove the entire plant and dispose of it with the residual waste.
Recognize
Soft rot is a bacterial pathogen that attacks young cucumber plants. Not only cucumbers are affected, but also many other types of vegetables, because the pathogens are very widespread in the soil. As soon as there are injuries, for example from eating or the flowers falling off, the bacteria can penetrate the cucumbers, which are decomposed from the inside out, although the skin is still intact.
Control/Prevention
You cannot control soft rot chemically. Destroying the affected plant alone ensures that the pathogens do not spread to other plants. Again, it is extremely important that you always water the cucumbers from below, never the leaves.
7. Angular leaf spot
Recognize
Leaf spot disease is also a bacterial infection that can be transmitted through the seeds. Especially in summer temperatures and humid weather, the pathogens can spread. thePathogens also survive in the soil and then penetrate the cucumber plants through injuries. She recognizes the disease by yellowish spots on the surface of the leaves. If the humidity is too high, droplets of slime form on the underside of the leaves.
The spots merge over time and turn brown, the leaves dry up and tear. As the disease progresses, the infestation can also spread to the cucumbers, which then rot.
Prevention
To prevent angular leaf spot disease, you should ventilate the greenhouse regularly. In the garden, a regular rotation of crops is important, because the leaf spot disease only affects cucurbits. If infested, do not grow plants from this family in the same spot for at least three years.
8. Cucumber Mosaic Virus
Detect
Small aphids are responsible for transmitting the cucumber mosaic virus. The transmission takes place within a very short time, because there are many host plants. The first signs appear after about 10 to 14 days. If the temperature is below 20 degrees, wilting occurs, and if the temperature exceeds 24 degrees, the typical mosaic spots appear. But it can also happen that these two phenomena overlap hand in hand.
These are mostly light spots that can be very different, depending on the virus strain. These spottings can also appear on the cucumbers, and wart-like structures also form here. The good thing is that the virus cannot survive on dead plant parts.
Control/Prevention
Since aphids transmit the virus, these pests must be controlled at an early stage. It is best to choose robust cucumber varieties when you buy them.