Sooty mold: what it is, how to identify this fungus and treatment to eliminate it

And just like that… there it is one day.

A kind of very bad looking soot that covers the leaves of your plants.

Does it ring a bell?

This is the most characteristic symptom of sooty mold, one of the many fungi that can infect our plants.


  • How exactly is bold produced?
  • Is it harmful to plants?
  • What can you do to prevent and eliminate it?

We will answer all these questions in this post.

If you are interested, keep reading!

Let's start at the beginning: what exactly is the sooty mold and how it is generated

If your plants have suffered an invasion of sooty mold more than once, you will have noticed that there is a pattern that repeats itself:

  1. An infestation of aphids, mealy bugs or whiteflies invades the plant.
  2. Shortly after, the leaves begin to be covered with that characteristic black powder of the sooty mold.

And it is not by chance.

What happens is that this fungus feeds on the molasses produced by these invasive species (the same molasses that also attracts ants) and uses it as a breeding ground to proliferate.

Therefore, if there is a plague of this type among your plants, it is likely that very soon you will see the sooty mold appear.

And what impact does it have on plants?

Here's the good news: sooty mold is rarely harmful to its host.

When they infect the plant, other more dangerous fungi (such as Phytophthora) devour the leaves and stems, and can even rot the roots.

But this is not the case of the sooty mold.

This fungus feeds on the molasses, not on the plant, so it does not get into it or damage it.

Yes indeed.

When the invasion of sooty mold is very serious, the fungus can cover the entire surface of the leaves, preventing them from carrying out photosynthesis.

If this happens, you will see that they weaken and end up dying.

But aside from that, the main problem with sooty mold is that it makes your plants look “dirty” and takes the shine off them. 

That is why we are going to see how to prevent it from appearing

How to prevent the sooty mold fungus on your plants

As we said, sooty mold usually appears after the invasion of insects such as aphids, which produce the molasses on which the fungus feeds.

So if you prevent these pests from occurring, you will eliminate the root problem.

For this you can use preventive phytosanitary products, which prevent the appearance of pests or reduce their impact.

If your plant is already suffering from the invasion of aphids, mealy bugs or flies, it is best to use an insecticide or acaricide to eradicate them, depending on the case.

What if it has already appeared? 3 methods to eliminate an invasion of sooty mold according to its severity

In the event that this fungus has already settled in your garden, the first step is to take care of the pest that has generated it.

Otherwise, they will continue to generate the molasses that the sooty mold uses to grow.

Once done, you can take care of eliminating the fungus itself. There are 3 methods to do this, depending on how extended it is.

1. Manual elimination

We told you that the fungus does not penetrate the plant, it only covers its stems and leaves. Therefore, if the infection is small, the easiest thing is to remove it by hand.

You only need to rub with a cloth (if it is wet, better) to drag the fungus.

You can also wash the area with water, but be very careful not to spread the fungus, along with the honeydew, to other nearby plants.

Pruning of the affected areas

When it accumulates in large quantities, the sooty mold ends up forming scabs that adhere to the leaves and stems.

In these cases, it is best to carry out sanitation pruning to eliminate the most affected parts, and thus prevent it from spreading further.

Use a topical fungicide

If the fungus has spread throughout the plant, the best way to save it is to resort to fungicides.

With this option, you not only make sure to eradicate the root fungus, but you will also prevent it from reappearing in the short term.

Combine it with a phytosanitary treatment to eradicate the pests that have caused its appearance, and thus prevent the cycle from repeating itself.

Do you already know how to eliminate the sooty mold from your plants?

Remember that in the product catalogue on our website, you can find specific phytosanitary products for your plants.

And if you have any questions, get in touch with us.

We will be happy to help you keep your plants healthy and happy.