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What Causes White Spots on Begonia Leaves? 4 Reasons

What Causes White Spots on Begonia Leaves? 4 Reasons

Begonias are mostly grown for their striking foliage, while some have vibrant flowers.

Begonias can grow between 1 to 3 feet (30-91cm). Their short stature allows for placements in any part of the house or office.

While Begonia’s are easy to take care of, many plant growers underestimate the task, which results in the plant becoming weaker.

One such condition is white spots on Begonia leaves.


What Causes White Spots on Begonia Leaves?

The white spotting on Begonia leaves is often the result of fungal infestations like Powdery Mildew or pest’s infestation like Mealybugs. Sometimes, excessive fertilization and low light conditions can also result in white spots forming on your Begonia leaves.

However, these can be easily avoided if we are careful about how we care for our Begonia.


Causes of White Spots on Begonia Leaves

White spots can quickly form on the leaves of a Begonia plant. Most of the time, it is due to negligence and improper care.

Reasons for the development of white spottings on your Begonia are:


1.Fungal Infection

Oidium species of fungi can cause an infection called Powdery Mildew. It is responsible for the formation of white spots on Begonia leaves.

This infection can be caused by infected soil, which eventually spreads to the plant. The fungi can also come from airborne spores of wild outdoor plants.

The fungi thrive in high humid conditions. Therefore, do not keep your Begonia in too much humidity.

Ensure that there is enough ventilation at all times. Also, as soon as you notice infected leaves, do not hesitate to prune them.

I spray sulfur or myclobutanil after pruning infected leaves. It usually stops the disease from growing further.


2.Fertilizer Overdose

Fertilizers are essential for a plant’s growth, but an excessive amount of fertilizer can result in an overdose. The plant takes up water by osmosis. However, the nutrients are pulled in by diffusion.

If the plant is forced to take up more of the nutrients due to water clogging, there will be an excess of certain minerals.

This results in white spots on the Begonia plant. These spots signify that your plant has too much one or more minerals which have resulted in patches of white spots.

This is the plant’s way of getting rid of all the excess nutrients. However, it does more damage than good. It is equivalent to human vomiting after overeating.

To prevent over-fertilization, read the label of the pack containing the fertilizers. It will give you an idea about the ratio of different nutrients.

Furthermore, organic fertilizers are a better choice than factory-produced ones. Natural organic brands slowly release nutrients into the soil.



Oedema is a condition in which rough swellings shaped like corks appear on the plant’s body. They are often white or yellow spots.

The most common trigger is low light and excessive watering. If this condition prevails for a long time, the Begonia leaves will turn yellow, droop and eventually fall.

It is impossible to recover parts of plants like leaves, but we can prune these parts to prevent further spreading of the disease. Repotting to better-drained soil often helps as well.



If you notice the white spots on your leaves moving around, then you are observing mealybugs. These pests often leave behind white residues, which are either their eggs or the bug themselves.

The mealybugs often leave behind sticky honeydew to attract insects. Therefore, if you find a white residue or sticky material, your plant has been infected by mealybugs.

To eliminate these pests, you can use natural pest control methods like neem oil or chemicals such as pesticides.

Often, they leave behind quite some damage, but you can prevent their infestation if quick action is taken.


Useful Tips to Prevent White Spots on Begonia Leaves

Following are some important points you should follow to prevent white spots on your Begonia’s leaves:

  1. Do not overwater your plant.
  2. Do not delay pruning dead leaves.
  3. Use natural fertilizers over chemical ones.
  4. Ensure your Begonia is in a well-lit room.
  5. Ensure your Begonia is in a ventilated space.


Caring for a Begonia Plant

Caring for a Begonia plant is not at all difficult. However, to make this a smooth sailing process, you must remember some pointers.

First of all, ensure that your plant is getting enough water. You must have good soil that always remains moist.

The soil should not be drenched with a lot of water. A well-drained potting mixture can prevent waterlogging issues. I water my Begonia plants at the base to avoid fungal growth.

Secondly, place your Begonia in rooms where temperatures are between 63 to 70 degrees Fahrenheit (17 to 21 degrees Celsius). These temperatures are ideal as Begonia’s prefer warmer and humid conditions.

Furthermore, plants like Begonia do not require a large amount of fertilizer. They do well with a balanced amount which should be given at least once a month.

The pot in which you place your plant also matters. There should be at least 2 inches of space around the roots inside a pot. A lot of space results in water collecting which prevents your Begonia from growing.

Lastly, don’t forget to prune your Begonia, or else you will find your plant dying.

This happens especially when too many dead or faded blooms are on the plant resulting in unnecessary energy being spent to keep the dead parts healthy.


Frequently Asked Questions about What Causes White Spots on Begonia Leaves


How do I know if my Begonia plant has a fungal infection?

Common symptoms associated with fungal infections are wilting and yellowing. In the case of white spots, you will notice water-soaked spots on the leaves.


Is leaf spotting on your Begonia contagious?

In comparison to fungal leaf spotting, bacterial ones are very contagious. Once infected, the disease travels to other plants nearby within a few hours.


Can vinegar treatment kill fungus on Begonia leaves?

A well-prepared vinegar mixture can ward off most fungal infections. The mixture should contain 1 part white distilled vinegar in 3 parts water, with a final touch of 3 drops of mild soap. Just spray the mixture directly at the white spots, and they should disappear.

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