Why are there Yellow Spots On Cucumber Leaves?

Yellow spots on cucumber leaves are caused because cucumbers themselves are susceptible to various diseases according to several studies that have been carried out. Most of it is contained in the ginormous leaves of the plant. A little will penetrate into the fruit.

All diseases will reduce the growth of the fruit though. Therefore, whenever you see yellow spots on cucumber leaves, it is important to identify the cause early on. Let’s look at the article from lavitaebellablog below.

Why are there yellow spots on the leaves of cucumbers?

Yellow spots on cucumber leaves

Yellow spots on the underside of cucumber leaves are usually caused by mite bites. Aphids can introduce cucumber mosaic virus resulting in yellow spots or scratches on leaves and fruits.

Yellow lesions on the upper part of the leaf surface indicate downy mildew – water fungus.  Yellow spots on cucumber leaves. Causes of yellow spots on cucumber leaves

Reason 1: for yellow spots on cucumber leaves – Downy Midew

Downy mildew is a water fungus. It can affect all plants in the cucurbit family. At the initial stage, it causes yellow spots on the tops of the leaves. It looks like blistered water.

When humidity is high, the underside of the leaves may show purple spores. However, unlike powdery mildew, which is a fungal infection that causes white spots on cucumber leaves , downy mildew is a water fungus caused by Pseudoperonospora cubensis – oomycete that is not a true fungus.

Early Signs in Yellow Spots On Cucumber Leaves – Downy Midew

Thus, it will not disappear. The initial signs are chlorosis ( yellowing of the leaves ) that spreads at warm temperatures that eventually leads to necrosis, which is evident when you see it turning into brown spots on the leaves of cucumbers .

The difference between downy mildew and similar diseases is that yellow spots turn brown with age of the leaves. It begins with yellow spots on the leaves, ends when all the surfaces of the leaves die off, that is, they turn brown and the leaves fall off the cucumber plant.

Downy mildew needs two conditions to develop. Wet leaves and warm weather.  It thrives at high humidity when temperatures are between 59-Fahrenheit and 68-Fahrenheit.  Since it is a water fungus, keeping the leaves dry by watering the soil can help prevent germination.

Overhead irrigation, such as using a garden sprinkler system can encourage fungal growth. The transmission can be through wind, splashes of water between plants, and tools that have not been sanitized.

Tips to Prevent Yellow Spots On Cucumber Leaves – Downy Mildew

For such reasons, temperature and humidity control is very important to prevent germination. Unless you grow resistant varieties of cucumbers, preliminary treatment with fungicides should be applied once a week.

Once detected in your area (not just your garden) increase the frequency of cucumber treatment once every 5 days. Diseases do not need to be present in your garden to affect your plants. It can be propagated by the environment.

Reason 2. for yellow spots on cucumber leaves – Mosaic Virus

Cucumber Mosaic Virus (CMV) is known to infect 150+ plants. Cucumber was the first plant identified, hence the name.  According to experts It is a soil-infected disease that kills the plants it infects.

Since it is in the soil, it will infect new plants so the plants need to be removed from the soil and the soil treated by solarization (heat treatment to kill soil diseases), or by planting in another area of your garden.

Remember that the best pH for growing vegetables and fruits is below 7.0.  Adding quality compost or humus may be necessary to ensure the plant gets all the nutrients it needs to fend off potential diseases.

Early Signs in Yellow Spots On Cucumber Leaves– Mosaic Virus

The problem is to identify CMV because its yellowing does not cover the entire surface of the leaf, but rather creates a different “mosaic” pattern.  Signs to watch out for are yellow veins on the underside of the leaves, variegated patterns, and/or yellow spots on the tops of the leaves.

Infected leaves also roll down and wrinkle. After the fruit begins to grow, a yellow spot may appear on the fruit, which indicates the cucumber is infected by the mosaic virus.  Unfortunately, there is no way to treat the mosaic virus. Infected plants need to be carefully removed, garden tools, and soil, sterilized.

Reason 3. for yellow spots on cucumber leaves – Well-known mites, aphids and whitefly

Mites , aphids , and whiteflies have one thing in common. They all make holes in the leaves to drink the sap. Aphids are the greatest threat to cucumbers because these insects carry and introduce the mosaic virus to plants.

Where the liquid is draine from the leaves, yellow spot occurs.  When the problem of insects is not treate in the first place, the damage becomes extensive. To the point that they can dry the plant from the liquid that causes it to die.

Aphids infestation on cucumber leaves

Heavy mite infestation can make the leaves of cucumber plants look like they are completely yellow. Look carefully and you will see a lot of small yellow spots fuse together.

The first sign of pest damage are yellow spots on the underside of the leaves. Insects hide and eat under the leaves. That’s where you’ll see the yellowest patches. As the population increases, the degree of damage causes a mottle pattern that looks like fuse spots.

A preventive measure is to repel pests by using a garden hose with a stream strong enough to knock out insects. Once this is starte, controlling them is usually necessary throughout the season.

Insecticidal soap or neem oil applie to the leaves twice a week helps prevent infestation. Another preventive step you can take is to apply peppermint spray to open wounds when you prune your plants .

Open wounds on the stems of the plant smell good-smelling insects. The smell of sap can attract garden pests. Cover the aroma, as it can prevent them from growing on the leaves of your plant.  Whitefly can cause yellowing of cucumber leaves

Frequently Ask Questions About Yellow Spots On Cucumber Leaves

What to do with cucumber plants infecte with leaf spot disease?

If mite damage is not the cause of yellow spot, it is likely that bacterial or fungal diseases need to be treate. For cucumbers, fungicides containing copper sulfate or copper octanoate are effective in preventing the spread.

Does the yellow spot on the leaves of cucumbers affect the fruit?

The less green the surface of the leaves, the smaller the surface of their photosynthesis. That is what causes stunte growth, reduce fruit size, and once defoliation begins, the fruits are at risk of exposure to sunlight. Fungicides can slow down or stop the spread, but if they continue, it may be best to exterminate the plant.

All farmers will be disturbe if some of their crops have a pest or disease. The disease will have a bad effect on growth and can cause losses during harvest.

One thing that often happens is the yellow spots that are on the leaves of cucumbers. Many do not yet know what is the cause of why it happene. Some people who are just farmers sometimes still have some surprises.

From that, the author discusses the ulusan about the yellow bitnik on the leaves of cucumbers. Hopefully, this information will be useful and increase knowledge about gardening.