If your plants look like they were too close to a bonfire, all covered in black soot, you more than likely have sooty mold problems.
It’s easy to identify from its unique look, but it can appear out of nowhere, before you even have a chance to spot it, leaving you wondering if you can fix it before it hurts your plant.
Luckily, you can stop sooty mold, but the pests that attract it can also damage your plants. Controlling pests is key in controlling this disease.
What Is Sooty Mold?
Sooty mold belongs to the plant mold family. It typically grows in honeydew, which is a secretion that comes from different pests that could infect your garden. Aphids and scales are two pests that secrete honeydew.
When these pests infest your plants, they cover the leaves and stem of your plants in honeydew. Then, the sooty mold spores discover and land on your plant, and reproduction begins.
Sooty mold is a surface contaminant; that means it doesn’t attack your plant directly. It needs nutrients to grow – aka honeydew. Honeydew is full of sugar and nutrients, and the mold uses that to grow.
It also prefers areas with poor air circulation and high humidity with long periods of wetness.
What’s This Honeydew?
We keep mentioning honeydew – but what is it? You know that some pests secrete this substance, but this doesn’t tell you much.
Here’s what you need to know.
Honeydew is a sweet, sticky liquid that plant-sucking insects excrete as they feed on the sap of your plant. After feeding on your plant, the insect is unable to digest all of the nutrients it acquired, so it excretes the waste – honeydew.
Honeydew can land anywhere that the pests might go. That means it can be on more than just your leaves, twigs, and branches. Pests leave honeydew on the fruit of the plants, the grass, concrete, sidewalk, and more.
Where honeydew is, sooty mold can grow.
Which Pests Produce Honeydew?
Thankfully, not all pests produce honeydew, so you don’t need to stress each time you see insects land on your plant. Remember, it only shows up on your plant with the presence of this substance.
The insects that produce honeydew include:
It’s crucial to know that both the larvae and adult stages of all of these insects produce honeydew while feeding on your plant.
Plants Typically Affected by Sooty Mold
Any plant can be affected by sooty mold; pests aren’t always picky about which plants they infest and feed. It can infect all plants from flowers to vegetable plants, like tomatoes.
Here are some of the trees and flowers that most commonly face this mold.
Symptoms of Sooty Mold on Your Plants
It looks just like you might think based on its name. You’ll find grimy, black soot covering your plant’s twigs, branches, and leaves. It typically looks like someone dumped ashes on your plant, but who is going to do that?
In reality, sooty mold discovered your garden!
In most cases, plants infected with sooty mold growth nearly always have a pest problem as well. So, the more susceptible your plants are to pests, the more likely it is that sooty mold will take over.
Here are the symptoms of sooty mold.
- Black or dark brown, fungal growth, particularly on the upper leaf surfaces.
- The growth can vary from fine soot to a powdery deposit to a thick sheet with cracks and peels.
- You discover the presence of sap-sucking pests on the plant.
- Sometimes, ants are attracted to the honeydew on the plants as well.
- Sooty mold tends to prefer new, tender plant growth. So, when you’re looking for the pests, make sure you always check new growth.
Will Sooty Mold Kill My Plants?
While ugly looking, sooty mold won’t usually kill your plants. It’s not a lethal mold growth. But the pests that secrete the honeydew COULD kill your plants.
While it rarely destroys your plants, it can stunt their growth and leave them vulnerable to the damage caused by the pests. Make sure to take care of the problem ASAP!
What sooty mold can do is reduce and dampen photosynthesis because it covers the leaves of your plant. This can slow or stunt the growth of your plant, while also making your ornamental plant less attractive.
On top of that, the appearance of sooty mold is an indicator that you have a serious pest problem. You need to figure out what pests are bothering your plants and get rid of them right away if you don’t want to lose your plants.
Can You Get Rid of Sooty Mold?
Yes, you can! All hope is not lost, thankfully.
Prevention is key, but if you already have a problem, your goal is to treat the source of the problems – the pests that excrete honeydew. Without honeydew, the mold is unable to live and thrive.
Here is what you need to do.
Figure Out What Pests Are Bugging Your Plants
Sooty mold comes as a result of untreated pest infestations. If you miss pests that are invading your garden and spreading honeydew long enough, you’ll end up with this plant mold on all of your flowers or vegetable garden.
The first thing you need to do is determine which pests you have. That can be hard with mold covering your plants; some pests blend right into it.
You might want to inspect near-by plants to see if any of them are infected as well. Pests rarely stick to one plant when they see lovely, untouched ones close!
Wash Your Plants
Now that you know what pests you’re dealing with, you can get rid of sooty mold by washing your plants with soapy water. This disease can easily be washed and wiped off of the leaves, stems, and branches.
You need to be careful and avoid strong soap and detergents because they can scorch the foliage. It’s also better if you use lukewarm water; it’s more effective at killing off of the spores.
All you need to do is mix 1 teaspoon of mild liquid soap with 1 gallon of water. Using a pump sprayer can make the job easier! Spray the plants and wipe each leaf to remove the disease.
It’s important to note that heavy infestations can take weeks or months to be washed away if you’re just waiting for the rain. That’s true even if you get rid of the pests causing the honeydew problems. So get the sprayer out!
Carefully Prune Your Plant
Another strategy is carefully pruning the severely infested plant parts. It’s also one way to keep out ants off of your plants.
When pruning your plants, use sharp shears that can cut the branches and twigs without causing additional damage. After you trim off the dead or damaged leaves, wipe the shears down with alcohol or bleach to kill off any mold spores that might live on the shears.
Apply Neem Oil
For organic gardeners, there aren’t too many effective choices out there for pests and fungus issues. Luckily, there’s neem oil, which can address both mold and pests.
If you use neem oil or any other horticultural oil, make sure you spray the underside of the leaves and treat every piece of foliage if you want it to be fully effective.
You should reapply the oil a second time 5-7 days if you still discover pests. First make sure that the plant isn’t suffering from any damage from the first application of the horticultural oil.
If you only had a small pest infestation, you should only require one application. Severe infections might require two applications.