Bacterial Leaf Spot on Monstera Signs

Bacterial Leaf Spot on Monstera Signs Image

As a plant expert for several years, I’ve dealt with a bacterial leaf spot on monstera plants countless times. And trust me. It’s pretty devastating. So, if your monstera plant has this bacterial disease, I’m sure it isn’t easy for you.

But what causes this bacterial leaf spot disease on monstera species? I’d say, in most cases, Xanthomonas and Pseudomonas cause a bacterial leaf spot monstera. 

In other cases, the Erwinia bacterium species can cause the fungal leaf spot on monstera. In this article, get to know these bacterial and fungal leaf spots in-depth. 

What Causes Bacterial Leaf Spot Monstera Plants?

If you’ve got an infected plant with leaf spots, blame it on a plant bacteria. This bacteria causes explicitly serious infections on monstera leaves. And as we said earlier, they’re caused by the following:

  • Pseudomonas
  • Xanthomonas
  • Erwinia

But in matters of the bacteria’s main predisposing factors, the following are the culprits:

  • Overwatering
  • Warm but moist environments

Moreover, this infection, in most cases, affects the household monstera species. A good example is the Monstera Deliciosa or half moon Monstera. Unfortunately, that makes me sad! I say so because I love keeping that specific monstera species.

Transferred From Another Plant

This bacteria on a monstera leaf spread from one plant to another rapidly. So, if in any way you’ve put your plants closer to each other, they may move. And the bad news is, your lovely plants will succumb faster, one after the other.

Often, your monstera plants may have black and brown spots erupting on them. That’s so because tiny bacteria spots can quickly transfer across small distances. Even more, they do so by insects, air currents, etc.


Another primary cause of these bacterial diseases on monstera leaves is overwatering. It causes the monstera soil to be wet and runny all the time. Moreover, when you’ve got soil with the following, it can become a contributing factor too:

  • Poor sunlight
  • Poor air circulation

That might be a contributing factor since the soil might become a bacteria breeding ground. Thus, causing the development of leaf spots on your affected plant. Again, that may cause root rot development on your adorable monstera plant. 

Watering your monstera when the soil’s top 3 inches isn’t dry is wrong. I say so because that means you’re overwatering your monstera plants. And that’s a bad thing. 

Also, it would help to check your pot’s drainage and the potting soil. If either stores water, then make some changes.

Moist and Humid Conditions

I must tell you this right now. High humidity is a fundamental care need for monstera plants. So, poor circulation and overwatering spell major doom. That’s true since the two produce favorable conditions in which bacteria thrive. 

Use of Infected Gardening Tools

Infected gardening tools and monstera pots are the biggest culprit in this bacterial infection. Unfortunately, some often forget to clean or wash their gardening tools well. Moreover, cleaning or washing isn’t the sole thing. 

It would help if you disinfected your gardening tools properly after using them. That’s why they often spread bacteria spots from one plant to another. And in that process, they end up infecting healthy plants.

Signs of Monstera Bacterial Leaf Spots

It’s a plus when you know the signs of this bacterial leaf spot. And that’s mainly on monstera plants. It’s a plus since it’ll help you identify quickly. 

Signs of Monstera Bacterial Leaf Spots Image

1. Dark spots on leaves

Among the common symptoms of a bacterial leaf spot, dark spots are the most common. Often, the dark spots pepper on monstera leaves. Further, in most cases, these dark spots appear first.

So, when you first spot them, know there’s something wrong.

2. Spots with yellow halos

If your monstera leaves have spots with yellow halos, then a bacteria exists.

3. Spots range in size

Your monster plant leaves may have irregular spots with widths. These widths may range between 3/16-inch and ½-inch. Moreover, these spots are either the following:

  • Circular
  • Irregular shape

4. Water-soaked spots

Also, you may notice some water-soaked spots appearing on your monstera leaves. But such spots typically appear on older leaves. 

5. Leaf collapse

Once the bacteria leaf spots progress, the affected monstera leaves may collapse. Further, several affected leaves may be littering the monstera soil’s top. Ensure you remove or discard the infected leaves immediately. 

6. Dry and papery spots

Older leaf spots may start drying and developing paper-like textures. Even when these spots turn dry, they’ll still retain the following:

  • Dark brown color
  • Black color
  • Reddish color

7. Discoloration of the leaves’ edges

Further, you may notice the leaves’ edges appearing discolored. That often happens immediately after the spots appear on the leaves. 

8. Oozy leaf spots

Some of the spots on the monstera leaves start oozing sticky bacterial substances. That may or may not happen. But when it does, it will appear on old and new leaf spots.

9. Leaf spots run together

Some spots start enlarging when you subject your monstera to extra wet conditions. Then afterward, they may run together.

That can cause significant portions of your monstera leaves to appear as a single big spot. 

10. Unpleasant odor

If you didn’t know, bacterial leaf spots sometimes cause unpleasant smells. So, if your monstera smells unpleasant, it has bacteria. Moreover, you’ll notice a musty or rot smell when this bacteria progresses.

11. Curling or Twisting of the Leaves

When the infection spreads over time, the monstera leaves become distorted. That’s a sign that your monstera is trying hard to fight against the bacteria. 

How Do You Treat Bacterial Leaf Spot on Monstera?

You can treat bacterial leaf spots in several ways. And since no effective chemical treatment exists, you can try a mechanical way. 

1. Reduce watering

Again, overwatering is a common cause of bacterial infections on monstera. Also, it’s the exact cause of fungal infections. If you notice this bacterial disease on your lovely monstera, reduce excessive watering.

Further, ensure you only water your monstera when the soil’s top inches feel dry.

2. Reduce the humidity level

Another factor that can aggravate/cause bacterial infections on your monstera is humidity. So, reducing humidity levels will help your monstera recover from the bacteria. 

3. Increase airflow

The monstera plant’s leaves need proper airflow to keep them dry and disease-free. If you’ve got a monstera too close to the rest, you’ll need to move it away. 

Remember, this air should flow via the monstera, reaching the leaves’ surface.

4. Prune infected leaves

It would help if you removed and discarded the infected leaves. However, keep in mind that overlying the plant’s prune is wrong. That’s so since removing some or most of the leaves will hurt your monstera.

5. Isolate the plant

It would be best if you kept your infected monstera away from the rest. Doing so helps stop bacterial leaf spots from spreading. Further, don’t overly touch your monstera.

Again, sanitize the pruning shears often after working on your diseased monstera.

6. Apply copper fungicide

Another thing. Chemical treatments aren’t effective when the bacterial leaf spot sets in. However, if you spot this bacteria early, you can control it. You can do so using copper fungicide. 

Ensure you follow the fungicide’s application instructions on its label. 

How to Prevent Bacterial Leaf Spot on Monstera

1. Avoid overwatering

One of the fast ways of causing bacterial issues is overwatering your monstera. But to help you keep your monstera plant healthy, water it when its soil feels dry.

To test the monstera soil, put your finger about two inches into the soil. If the soil feels damp, redo the test after a day or two. 

2. Properly care for the monstera

Providing your monstera with ideal growing conditions will help keep it healthy/happy. Also, that prevents bacterial leaf spots from happening. 

Further, your monstera can quickly recover from this bacterial infection. But that’s if only it’s strong and healthy.

3. Don’t overcrowd the plant

When you place your monstera and other plants closer, air blockage will occur. Thus, no air will flow through your plants freely. Moreover, with poor airflow, moisture on the monstera plant’s leaves won’t dry properly.

Because of that, the chances of diseases like the bacterial leaf spot will increase.

4. Remove any fallen leaf debris

Leaving leaf debris on the soil’s top can turn into a host for problems and pests. Apart from encouraging the development of bacterial leaf spots, it can also cause:

  • Rot
  • Insects
  • Other fungal diseases

What’s the Difference Between Monstera Fungal Infection and Bacterial Leaf Spot?

Fungus or bacteria can cause leaf spots on your monstera plant. Moreover, leaf spots from the two look similar. Then again, distinguishing them might be challenging. 

But, the good news is that spots from the two have similar prevention and treatment measures. It’s somewhat highly challenging to differentiate bacterial and fungal spots on monstera.

It’s so challenging that most plant parents don’t bother if it’s fungal or bacterial. Instead, they jump right into it and start treating the issue. That’s because both bacterial and fungal leaf spots need similar treatment.

Even better, they need similar preventive measures.

1. Appearance of spots

Often, bacterial leaf spots have an extra angular look, unlike fungal leaf spots. But that isn’t a hard-fast rule.

2. Yellow halo around spots

Also, bacterial leaf spots can have yellow halos around them. However, some of the spots aren’t a result of bacteria. 

Moreover, some can lack yellow halos.

3. Soft rot can occur on the leaves

In some cases, bacterial leaf spots may cause soft rot to develop on the leaves. That can happen at the leaf’s tip, then extend upward. Or, the soft rot may appear in the leaf’s middle. 

Unfortunately, some fungal pathogens can cause soft rot on the monstera leaves. 


What does bacterial leaf spot look like?

Often, bacterial leaf spot starts as small dark brown or black spots. Moreover, these spots may have halos of yellow tissue that can surround each spot. In other cases, the leaf’s center may dry up, falling out. Afterwards, it may give the leaf appearance similar to a “shot hole.”

How do you treat a fungal infection in monstera?

Prune the infected leaves. Doing so helps prevent the spread of the fungal infection in your monstera. And that’s because root rot is often a fungal problem. Also, pruning the infected leaves helps clear ugly brown spots. Luckily enough, monstera plants respond positively to pruning.

Does bacterial leaf spot spread?

Yes, bacteria on a plant’s surface can quickly spread to other close-by plants. The spread happens via water splashes from irrigation and rain. Asymptomatic plants sometimes serve as an inoculum source. 

Is bacterial leaf spot contagious?

Yes, this bacterial leaf spot disease is highly contagious. Moreover, excess water splashes (irrigation or rain) spread their pathogen. Further, the following also spread the disease’s pathogen:

  • Leaf pruning and harvesting tools.
  • People walking past infected plants

Can you save a plant from bacterial leaf spot?

Yes, you can save plants from a bacterial leaf spot. You can irrigate the plant’s leaves when they become dry. That’ll help reduce its spread. It’s worth noting that splashing water can move this bacteria, infecting new leaves.

Further, eliminating wet leaves will stop this disease’s spread completely. Also, it may help prevent bacterial spot appearance. 


As we’ve seen, bacterial leaf spot on monstera is inevitable. Apart from pruning and irrigation, you can clear this bacterial infection using the following:

  • Baking soda
  • Neem oil
  • Bacterial agents

But over and above, preventing the bacteria is the best solution. So please, continuously improve your monstera’s air circulation and moisture needs.

Also, note that your monstera needs a lot of warmth and sunshine. 

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