Bacterial Leaf Spot Monstera( Causes and Treatment) - TasteCatcher
Bacterial Leaf Spot monstera

Bacterial Leaf Spot Monstera( Causes and Treatment)

Indeed monstera plants are known for their foliage beauty. Its broad, green, and luscious leaves add to the charm and beauty of your homes and offices.

But all of sudden, you begin to notice black spots or patches on leaves that are continuously changing in their color. These dark black spots on monster leaves are called bacterial leaf spot monsters. 

Not only monstera but many edible and ornamental plants leave exhibit black spots on their leaves. This is also a sign of bacterial leaf spot disease. This bacterial disease can discolor the leaves and in extreme cases can kill the whole leave.

It is very challenging to treat bacterial infections. Fungal infection is quite a different term and is also treated by different methods. Bacterial infections are dangerous for plants when they get severe in an early case it is treatable. 

If you are noticing these black spots on your monstera then don’t be a worry. In this article, we will discuss all the possible causes and treatments of this bacterial leaf spot disease.

Let’s have a look at this!

Table of content:

  1. What is bacterial leaf spot disease ( in monstera)

  2. Sign and symptoms

  3. POssible cause of bacterial leaf spot monstera

  4. Treatment

  5. Preventive measures.

  6. Final verdict.

Bacterial leaf spot disease (signs and Symptoms)

To examine the signs and symptoms, have a close look at your monster plant and try to check whether it is a bacterial or fungal infection. If you don’t know the difference between bacterial and fungal infection then don’t worry. We are here to distinguish these terms. 

Check the surface area, underside, and stem of plants. If you observe the given below symptoms then it is clear that your monster is suffering from bacterial infection.

  • Surface and the bottom area of leaves

  • Brown, yellow, and dark color spots on leaves.

  • Dark color spots underneath the leaf surface.

  • Spots that ooze the sap.

  • Blacked-edged lesions.

  • Spots are regular in size.

  • these spots measure between 3/6 and 1/2 inches.

  • Black spots on the edges.

  • the leaves become papery and look dried.

  • This disease attacks older leaves but may also develop on newer leaves.

  • In severe cases, the leaves get damaged and eventually die.

When the monster plant is not showing good growth. Emerging leaves also have black browned or yellowish spots on them. All these things are also a sign of bacterial disease.

But if your plant is suffering from a fungal infection and you took it to a bacterial infection and begin to treat it accordingly. Then there will be no benefit to doing so. You must know the difference between these two terms. 

In case of fungal infection, you will notice Fungal spores. Fungus when attacked by an organism will reproduce in the form of spores. So fungal infection will indicate spores production on leaves.

Temperature and humidity favor the growth of fungi and make them grow more on plants.

This bacterial leaf spot disease is quite dangerous for plants if not detected and treated. But here are some possible causes of this bacterial leaf spot disease, try to avoid these causes and save your plants.

Causes of bacterial leaf spot disease in monsters:

Bacterias are so small that can’t be seen with the naked eye. The invisible microorganisms are the cause of this bacterial leaf spot disease. Moreover, wet, cool, and humid conditions make the bacteria to become more powerful.

Once these bacteria attack your plants, they will spread to healthy ones in no time. Bacteria generate more quickly in temperatures between 77 to 86 degrees F.

Other possible causes are:


One of the most common causes of this bacterial disease is root rot. This root rot happens when you water your plant more than the required amount. Beginners often do this blunder with their plants by watering them too much. Plants do not need much water as we imagine the amount.

Overwatering can easily lead to root rot and hence allowing the bacteria to stay on plants. Try to avoid overwatering. Make sure that before watering the soil is completely dry. In the winter season, most plants do not show any growth so therefore you should minimize the water supply to plants.

Direct sunlight

Not only monstera, but all the plants native to rainforest areas also cannot withstand direct sunlight. When you are exposing your plants to direct sunlight for a longer time they get easily burnt.

One of the common causes of these black or brown spots on monstera and other rainforest plants is direct exposure to sunlight. Try to avoid direct exposure and save your plants.


The monster plants require a handsome amount of water to sustain a healthy life.

In case of a shortage of water, the plant’s leaves begin to shrink in size. The most common symptoms that appear after water shortage in plants are black spots on leaves. Water shortage is a serious issue and can lead to bacterial leaf spots more easily.

Try to avoid water shortage. Make a schedule to water your plants. Don’t exceed the water supply, especially in the winter season when plants do not show any growth.

Physical damage

Another reason for these bacterial spots on leaves is physical damage. Plants get damaged when they are exposed to touch during their growth period.

Plants’ leaves are so sensitive. They can easily be prone to these black or dark color spots when exposed to touch during the growth period.

Leaves are so delicate even a touch can lead to damage during their growth period. When plants grow to their full size or become mature, they will attempt to heal themselves. That’s why you begin to notice a brown spot at the edges of the leaves.

Excessive misting

Monstera plants are humidity lovers. These plants love to live in a humid environment. But if your house is low in humidity then it may lead to excessive misting.

A humidity level below 40% can lead to excessive misting. Monstera is a great humidity lover. Low humidity can easily cause bacterial infection. Try to increase the humidity of your house by having a humidifier (check it on Amazon).

Cold temperature

The monstera is an indoor and tropical plant that usually does not like cold weather. If you keep your monster outside they easily get cooled and become sick. when you keep them inside, they remain safe and good. But all of sudden moving them outside can cause the bacterial leaf spot disease easily.

The most common cause of this bacterial leaf spot disease in monstera is cold weather. In cold weather, most plants lose their immunity and are hence easily attacked by bacteria and fungus. In case of losing immunity in cold weather, they can easily get black spots.

Treatment of bacterial leaf black spots disease in monstera

Follow the given steps and you can easily save your favorite plants. These guidelines are not only helpful in the case of monstera, any other plant suffering from bacterial disease can be saved.

Step 1:

Separate the infected plant( quarantine)

The first and most important thing to do is to separate the infected plants from the other healthy ones. This bacterial disease is viral and can easily damaged the other healthy plants and leaves.

The bacterial disease spread slowly and is insidious. Once it attack your monstera plant then it is quite sure that other healthy plants are also not safe.

In this case, move your infected monstera to a separate place like your balcony or a porch where there is an indirect supply of sunlight. This place will be best for damaged and sick plants.

Step 2:

Trim off  the damaged leaves

Once your monstera is attacked by bacteria or black spots beginning to appear on it. At that time, you have t take great care of your plant to save it from serious damage.

Cut the already burnt or damaged leaves with a sterilized sharp scissor. In case of root rot, cut the damaged roots also. Now take out the plant from its pot. Carefully wash its roots and remove the soil attach to them.

Shift the monstera to a jar filled with water at room temperature. Make sure that only its leaves are dipped in water. Change the water to a jar after a few days. Doing so will be effective in removing the black spots on leaves.

Step 3:

Indirect sunlight

Monstera usually does not like cold weather but it doesn’t meant that they survive well in direct sunlight or hot weather. Direct light is the most common and effective cause of these black spots on leaves.

Try to avoid direct exposure to sunlight for a longer period. Move your monstera inside or indoors at such a place where they receive filtered or indirect light. Place the monstera near a window that is covered by a share curtain.

Step 4:

Appropriate watering

Shortage of water can be a cause of black spots o monstera. When plants are receiving a small amount of water they begin to store their water as a result bacterial leaf spots can easily attack them.

Make sure that before watering the soil is completely dry. But if you have not watered your plant for a longer time then you will notice the soil is completely dry and it becomes hard. In this case, soak the soil in water for a few days until you see the dampness in the soil. In case of a shortage of water mostly the soil becomes hydrophobic hence stopping the plants to absorb water.

After you allow to stand the soil in water for a few days, it will become rehydrated and adapt o absorb water more proficiently.

Step 5:

Temperature and humidity

Monstera usually stops growing in the winter season. In the winter season, they easily lose their immunity hence prone to bacterial infection.

In the winter season, it will be good to keep your monster at some hot place. Regularly exposed to the hot environment in cold weather. Make sure that your plants are receiving enough sunlight in the winter season to prevent bacterial infection.

Monstera plants are humidity lovers. If your home is low in humidity then try to increase the humidity level by using a humidifier. Keep the washroom doors open after taking a bath. It will ensure an increased humidity level for a little time. Try to keep your plants near the kitchen to ensure the humidity is balanced.


Read more about monsters like humidity or not?

Preventive measure

Unfortunately, If your plant has suffered from black spot leaf disease then this is the best time to save the healthy plants from being infected.

  • Make a schedule to water your plants. Only water them when their upper 2 inches of soil is dry.
  • Dry spells create a hostile environment and increase their immunity against bacterial infection.
  • Maintain a good humid environment for your monsters.
  • Keep them in a hot environment in winter to prevent bacterial infection.
  • A humidity level of 50 to 60 percent is pretty good for their luscious greenery and growth.
  • Maintain the hygiene of your garden or the place where you keep the plants.
  • Never allow standing water in pots.
  • Always use fresh and clean water for plants.

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