Black Spots on Succulent Leaves: What to Do

One of the most common problems you may face is black spots on succulent leaves. 

I have faced this issue on many occasions. For this reason, I don’t think you can avoid it unless you have some experience.

Furthermore, its causes are often unclear. 

Therefore, you could waste time searching out the right solution while your plant is dying. Indeed, getting rid of those spots or treating them depends on the correct diagnosis.

You have probably been asking: Why does my succulent have spots on its leaves?

Overall, there are seven reasons for those black spots. Those reasons range from unmet temperature needs to invasive bugs. We will see below a detailed list to help you solve this issue.

However, it is crucial to differentiate between tiny black dots and large dark specks before going further.

Also, there is a difference between mushy spots and dry ones. In addition, the number and size of the spots are relevant factors.

Here is my advice for you: Determining what kind of spots you are dealing with will get you a long way to finding the cause.

So, in this article, I will present each cause, its signs, and its solution.

Read also: Pink Panther Plant Care: Complete Guide

PESTS

I will start with the most difficult cause you may face: pests. It is also the easiest to spot.

In general, if your succulent shows tiny black dots on its leaves, then you don’t need to look any further.

Pests such as mealybugs and aphids feed on succulents and leave numerous dark marks.

Also, snails and slugs will damage your plant’s foliage by eating small chunks.

Now, let us delve more into the subject.

Aphids

These bugs are a big annoyance because they are difficult to exterminate when in large numbers.

Aphids will feed on your plant’s leaves and reproduce at a high rate. So, you could find yourself facing a large colony in a matter of two days.

Additionally, the dark marks left by these pests won’t disappear. Therefore, you will need to wait for your succulent plant to overgrow them.

Now, the first thing you have to do is move the succulent away from your other plants.

Then, you can start by eradicating the pests, and here is how.

First, start by spotting them to determine their numbers. Aphids come in different colors: Black, brown, orange, and green.

If you’re dealing with a small number, then you can use a toothpick to kill every last one of them. Then, wash off the plant thoroughly.

However, if you’re dealing with a large colony, then pesticides are required.

Because pesticides can kill off beneficial insects, it is best to use them only at night when these insects aren’t flying around.

Also, pyrethrum-based sprays are an adequate solution to this problem, while neem-oil sprays aren’t that effective.

Last, I would suggest you check on your other plants to make sure they weren’t infected as well.

Mealybugs

Mealybugs are even more difficult to eliminate due to their protective shell.

In addition to being resistant to pesticides, Mealybugs are quick to spread. So, if you are late in spotting them, you will have an army to face.

Furthermore, they are extremely good at hiding. You will have to inspect every inch of your plant to find them.

Mostly, Mealybugs will hide between the stem and the leaves or under the pot.

Also, they will lay their numerous eggs right at the base of the plant. That way, the baby bugs will easily survive when they hatch.

Therefore, the best way to avoid them is to keep your garden clean and tidy.

I would suggest you remove any dust or dead leaves that may be on the ground.

When it comes to getting rid of Mealybugs, you can do it in two ways.

First, just like for Aphids, you can use a toothpick to crush any visible bugs. However, you won’t be able to kill them all in the case of a large colony.

Consequently, you can use an isopropyl solution to exterminate them.

Owing to the resistant nature of these pests, I recommend multiple applications for an extended period.

With that in mind, keep inspecting the plant during the treatment period to make sure that the bugs haven’t returned.

Finally, don’t put the succulent back with your other plants unless you are sure all the mealybugs are gone.

Ants

The problem with ants is that they defend and farm aphids and mealybugs.

Because they feed on their honeydew, Ants will favor the spread of these pests.

Accordingly, you will often have to deal with ants when facing aphids and mealybugs.

Furthermore, ants are even more difficult to eradicate than other bugs. Indeed, killing off the workers won’t be enough to stop them since their queen will be producing others in no time.

From my experience, there is no quick recipe or solution to eliminate ants. I believe that the only thing you can do is keep your garden clean at all times.

It will take energy and time, but it is the most efficient way to get rid of them.

Slugs and Snails

The last pests on this list are slugs and snails. These seemingly harmless creatures will poke small holes in your succulents’ leaves.

Then, when the plant heals itself, the holes will turn into dark marks.

Luckily, snails and slugs are easy to kill. You can use a beer trap to that effect, and they will drink themselves to death.

Here is another kind of trap you can use: Disposable Snail Traps

Advice:

As I have explained, pests are generally a challenging problem. It will take time and effort to deal with them with often uncertain results.

Therefore, it is best to prevent them from ever infesting your garden.

First, you should always clean your garden and pots. Dust, dead leaves, and old soil will ultimately attract bugs.

Second, you should take the time to inspect each plant when watering them. By spending two minutes on each plant, you can detect any early invasion. Thus, you will be able to treat the issue more efficiently.

Provided that you follow these two simple pieces of advice, you will never have to face those bugs.

FUNGUS, ROT & WATER WARTS

The next cause on this list is funguses, rot, and water warts.

Succulents suffer from these diseases in humid areas. Therefore, it is likely that your succulent has round black spots because of moisture in the air.

Those round-shaped spots will eventually cover the entire leaf before it falls off.

Furthermore, spraying your succulent plant with water can also be a cause.

Succulents don’t absorb water that way. Therefore, spraying them will only harm them by causing fungi and rot.

In short, if you live in a highly humid area and your succulent has round black specks, then you know the source of this problem.

The solution is to use a fungicide every other week. My advice is to use organic ones and only at night.

Because humidity is the main factor here, you’ll likely be facing this problem multiple times. Therefore, it will require patience and a strong will to sustain your garden’s health.

Another thing to keep in mind is that your plant may not give you the time to save it. Indeed, in some cases, the fungus spreads too fast and kills the plant in a matter of days.

OVERWATERING

Next is the mother of all killers: Overwatering.

I don’t know any gardener that hasn’t lost a succulent or two to overwatering.

It is the first hard lesson you learn as a beginner.

Succulents store water in their roots, stems, and leaves. That way, they can endure arid climate conditions in the wild.

So, when you give them too much water, you risk killing them.

What happens is that the leaves get overfilled and burst. They first turn translucent before turning black due to fungal diseases.

These black spots will feel soft and mushy, while the whole leaf will look swollen.

If this is the case for your plant, you may be able to save it.

First, you should remove the affected leaves.

Second, you will have to repot the succulent in a new medium.

By removing the plant from its current pot, you can check its roots. Next, cut off any black and mushy roots before planting your succulent in a well-draining potting mix.

Moreover, you must dispose of the old soil and pot because they probably carry fungi.

Furthermore, if the black spots have spread to the stem, there isn’t much you can do. The only solution left is to propagate any healthy parts left through cuttings.

Last, it is best to err on the underwatering side and follow the soak-and-dray method. It will save you many headaches.

Read also: Underwatered Succulents: What You Need To Know

SUNBURN

Sunburn feels like a weird one, but I assure you it does happen.

Succulents do get sunburn if exposed to scorching sun rays. 

Temperatures above 100°F (38°C) are harmful to succulents planted in pots, especially if they have to withstand it for a long time.

By contrast, those planted in the ground are more enduring because their roots keep them cool.

That said, succulents that suffer from sunburn will show dry and hard black spots on their leaves (see the photo below). 

Now, you will have to remove the affected leaves and acclimate your plant to prolonged sun exposure.

Indeed, those leaves won’t heal, and your plant will be better off.

You can start by reducing their time outdoors to 4 hours a day for three days.

Then, increase their time in the sun for one hour each day until they get used to it.

With that in mind, you should always acclimate your new plants to sun exposure, or they will face the same fate.

If your plants are hard to move, then you can use an umbrella or a sunblock shade cloth during the hot periods of the day.

FROST

Just like sunburns, and unlike overwatering, frost damage will mark the succulent leaves with dry black spots.

Temperatures under 32°F (0°C) will negatively affect your succulent plants. 

Therefore, it is best to move the pots indoors if you live in an area where temperatures are freezing.

On the other hand, if they don’t drop below 32°F, a simple frost cloth will do the trick.

If your succulent plant has signs of frost attack, you will have to remove the damaged leaves. 

However, if the attack has reached the top of the plant, your only solution is to propagate it with cuttings.

Read also: This is a Succulent Plant that Looks Like Coral

TRAUMA

Trauma is the easiest to spot. If this is the reason your succulent has black spots on its leaves, then you will know it right away.

Scratches and scrapes due to poor handling can lead to those dark marks.

For instance, when repotting your plant, you can inadvertently cause “bruises” on its foliage.

Furthermore, succulents that have a farina coating (wax that forms a white or blueish-silver film on the leaves) are more susceptible to this.

Unfortunately, you can do nothing except wait for the plant to overgrow them.

For this reason, it is necessary to handle your plants carefully to prevent them from getting damaged.

VIRUS

The last cause on this list is viral infections.

The black ring virus causes black spots on the underside of the leaves. Your succulent may have caught the virus from an insect infestation or an infected knife.

For this reason, you need to sterilize your tools before using them on your plants.

Also, preventing insect invasion is essential to avoid this kind of infection.

The bad news is viral infections have no treatment. So, you either discard the whole plant or remove the infected leaves and quarantine the plant.

FAQ

CONCLUSION

To sum up, there are many causes of black spots on succulent leaves. 

Consequently, to determine the correct one, you will have to examine the nature of these spots.

While tiny black dots are a clear sign of pest infection, large dry specks are due to sunburns.

Unfortunately, those spots will never go away, and you will have to cut the leaves off.

However, your succulent plant will grow new healthy leaves as long as you give it adequate treatment.