How to Identify and Treat Common Indoor Plant Diseases

common indoor plant diseases

There is nothing worse than seeing your plants die at the hands of indoor plant diseases, while you sit there helplessly wondering where you went wrong. As a plant parent who has just started out; identifying and treating these diseases may seem overwhelming to you. However, do not fret! This article covers all the common indoor plant diseases that may potentially hit your plants. However, it goes without saying that you can take care of the basics to prevent your plants from reaching this stage.
This includes providing them the right temperature, water, and humidity level. Overcrowding also plays a crucial role in keeping your plants safe from future afflictions.

3 Indoor Plant Diseases that are a Major Threat to your Plants

Powdery mildew

Caused by a fungus, powdery mildew is the most common and least dangerous of all the diseases. It is rarely fatal and just leaves your plants weak and deformed. This can easily be cured with proper care, so you can relax.


Powdery mildew is distinguished by a white powder-like appearance on the leaves. If left unattended, it spreads to the stems and flowers. This fungal infection leaves your plant extremely weak resulting in leaves drop.


The major cause of this fungal infection is compromised air circulation. Then comes high temperature and humidity along with overcrowding and overwatering.

  • Remove the infected leaves carefully such that the fungal spores do not spread further
  • Clean the plant pot of any fallen, infected leaves
  • Do not keep your plant under direct sunlight and reduce the humidity level
  • Improve the air circulation

Root rot

This is another common indoor plant disease caused by a fungus. What is interesting is the fact that the fungus that causes this disease lives in the soil all the time. Does this mean your plants are always infected? No! This is because this fungus is only triggered with excessive watering causing your roots to rot.


Root rot is characterized by wilting and brown or black lower parts of the plants. However, in extreme cases, you can see it traveling to higher parts too. Furthermore, the roots turn black instead of the usual white color and leave a pungent smell.


Overwatering is the enemy of plants and root rot is the prime example of it. Poor drainage and excessive watering is a major cause of this disease.


If it is the start of the disease and no part of the plant except the roots have been affected, you can try taking out the roots and spraying them with a fungicide.

However, the symptoms usually show when it's already too late and there is nothing you can do apart from throwing away the rotten part and using the healthy cuttings to start a new one.

Fungal and bacterial leaf spots

While fungal leaf spots are not lethal, bacterial spots almost always result in a dying plant. Fungal leaf spots often result in leaf drop without any substantial effect on the plant.

Identification of fungal spots

There are a lot of fungi that cause yellow, white and black leaf spots, with the same identification and treatment methods.

Identification of bacterial spots

Bacterial leaf spots are water-soaked, black or yellow areas that may travel to the whole plant. If only the leaves are infected, the plant can be saved. However, if it has already infected other foliage including the stem there is nothing you can do to save the plant.


Overwatering and fallen leaf debris are the most probable causes of all types of indoor plant diseases. Increased humidity levels are also a contributing factor.


  • Decrease humidity level
  • Remove infected leaves
  • Do not reuse infected potting
  • Increase the air circulation

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