Common Houseplant Diseases – Identification & Treatment

No matter how well you take care of your plant, watering, feeding, pruning, there is still a chance that your plant can contact some type of household plant disease.

If you see that your plant is not looking as it should, such as yellow leaves, dropping leaves, no growth, you need to start finding out what it is and the treatment before you lose the plant.

Houseplant Diseases and Treatment

Keeping your houseplant healthy will help them to resist and fight off diseases a lot better than weak houseplants.  Sometimes, no matter what you do, your houseplant may get some type of disease but if you catch it in time and treat it, you may not lose your houseplant.

1. Stem and crown rot

This houseplant disease is caused by the fungal mycelia. This fungal is found in most soils and will generally live with the houseplant but if the conditions become very damp it can become a problem.  A houseplant can become damp through cool conditions, over-watering, or poor ventilation where it will multiply rapidly.

  • Symptoms:  You will start to see discolored or black rotten patches at the base.  This is because the base is the closest part to the soil.  With this fungus, it is possible that it will infect other parts of the plant.  The houseplants most at risk are cacti and other succulents
  • Treatment:  The only thing you can do is cut out the rot and dust it with an anti-fungicide.  If the base has been badly affected you may have to cut out the entire lower section of the plant. This will most likely kill the houseplant so you should take cuttings from the healthy parts and try to propagate the plant.

2. Grey mold

This disease is caused by an airborne fungal.  It will land on dying or damaged tissue of the houseplant.  On plants, it is normal to have small wounds.  It should not be a problem if the conditions are reasonably dry and the plant is healthy.  The problem happens if the surrounding atmosphere is cool and humid and you have a weak houseplant.

  • Symptoms: You will first notice some soft rotting patches that will soon be covered in a grey fungus.  There will probably be dead brown patches on the stems or leaves or rotting bulbs or pale brown or white spots on the flower petals.
  • Treatment:  The first thing to do is to remove the parts of the houseplant that are affected.  You then need to improve the ventilation or find a way to reduce the humidity in the area.  You may have to throw the plant away if the grey mold has gotten out of hand.
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3. Powdery mildew

This houseplant disease is more disfiguring than fatal.  It is not overly common on household plants kept indoors.  The reason is that the fungi spores that cause this disease to travel through the wind.  If you are keeping your houseplants outside during the summer then the risk of them developing this disease increases.  It generally occurs when plants are very close together or the location is warm and damp.

  • Symptoms:  The leaves will be coated with a white film that looks like a light dusting of flour.  Over time the white look may dull and get darker.  If you do not catch it in time, it will spread over the whole plant, including the flowers and stem.
  • Treatment:  Carefully remove the badly infected mildewed leaves.  You do not want to rush taking them off because you could create a wind that will blow the spores to the other plants.  You will then need to dust the leaves with Sulphur to give you control over the disease.  You can also spray with a product that contains Myclobutanil Penconazole, Flutriafol.
plant yellow leaf 1

4. Nutrient deficiency

Nutrient deficiency is quite probable if you have never repotted or fed your plant.  Most plants will make their food through photosynthesis.  The plants still will need small levels of nutrients to ensure a healthy look and to sustain new growth.  The nutrients are found in the soil but once the nutrients are gone, they are gone.  This is why you must replace these nutrients by changing the soil or fertilizing.

  • Symptoms: There are really too many symptoms to mention but generally you can tell they have a nutrient deficiency by poor or unusual growth.  The leaves could have odd shapes and be very small, discolored flowers or no flowers at all, plant color could be transparent or dull in place, and more.
  • Treatment:  The immediate treatment is to repot the plant using fresh soil or to fertilize using an all-purpose mixture.  Just use one to start with because if you use both, it could damage the plant more.  If you decide to repot the plant, then you need to wait at least eight weeks before you start to fertilize it.
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5. Viruses

This is a broad topic and all have varied symptoms.  Most houseplants can be affected.  Generally, they are spread by Aphids or other insects.  Since there are so many symptoms we will not list them but will say there is no cure.  You will usually have to throw it away without propagating any part of the plant because there is a high chance the virus will remain and affect the new plants.


These are just some of the many diseases that can affect your houseplant.  To keep your houseplant from developing any disease, keep it healthy.  Make sure that you are giving it the proper amount of water, the right light, the right soil, and the right temperature and humidity level.  All of these things will help to keep your plant healthy and help to thwart diseases.  If you notice that your plant has yellowing leaves, droopy leaves, developing weird areas on the plant anywhere, it could be some houseplant disease.  Find out what it is and take care of it before your plant cannot be treated and you have to throw it away.