Gnats – or fungus gnats, to be more specific – are insects that can be seen flying around plants, and this includes succulents.
Fungus gnats are usually drawn to succulents that have been overwatered, or are planted in the wrong type of soil. The gnats are actually attracted to the fungi that grow in the conditions listed above. So, if there is no fungus, there will be no fungus gnats.
In this article, we will discuss the reasons that succulents might attract fungus gnats, how to get rid of fungus gnats, and how to keep fungus gnats aways from your succulents.
If you are currently experiencing this problem and you want to learn more about it, then keep reading.
What are fungus gnats?
Fungus gnats, also called sciarid flies, are small insects, about the size of a fruit fly, that mostly affect houseplants.
They tend to show up seasonally, so if you have had an infestation, the next time the same season rolls around, you might have to be on the lookout for gnats again.
Fungus gnats look very similar to fruit flies, but fruit flies tend to stick to rotting fruit while fungus gnats prefer soggy soil.
Succulents in pots and containers that do not have proper drainage are the perfect target for fungus gnats.
Where do fungus gnats come from?
Fungus gnats will generally appear when they find a succulent with constantly wet soil in a pot with poor drainage. If you do not clear the fallen leaves from around the base of the plant, and instead leave them to rot on the soil, this can also lead to a fungus gnat infestation.
A newly purchased plant that you have just brought home from the nursery or the store may have gnats in it already. Even potting mix that you bought from the store can be a gateway for these pests to find their way onto your succulents.
There might not be actual gnats flying around the plant, but there could be eggs hidden away that you are unable to spot upon first inspection.
What are the signs of a fungus gnat infestation on succulents?
Aside from actually seeing the bugs flying around or crawling on the succulent to verify a fungus gnat infestation, there are other signs you can watch out for.
These tell-tale signs include yellowing of the leaves, stunted growth, loss of vigor and sudden wilting of the leaves.
These symptoms are quite similar to those of root rot, and root rot is a definite possibility considering that fungus gnats love overwatered succulents. However, if you check the plant’s roots and there is no rot, then you are most likely looking at a fungus gnat infestation.
What attracts fungus gnats to succulents?
Too much water
Because succulents are able to store water in their fleshy leaves, they do not need to be watered as often as other plants. For this reason, it is very easy to overwater them, especially if their pots do not have drainage holes at the bottom.
To correctly water your succulent, you need to wait for the potting mix to dry out completely before watering it again.
If your succulent is overwatered, fungus gnats will be attracted to the excess moisture, since this is the perfect type of ground for them to lay their eggs in.
Within days, the eggs will begin to hatch and, in a matter of weeks, you will be dealing with a full-blown fungus gnat infestation.
Incorrect potting mix
Another reason your succulents can get fungus gnats is if you are using the wrong potting mix.
Succulents like a well-draining potting mix that is a mixture of organic and inorganic material.
You might have bought commercially-available potting mix from the store, but that does not automatically mean that this mix is the perfect one for your succulents. Sometimes these pre-mixed potting soils are way too dense and will end up absorbing too much water.
The excess water in the potting mix can lead to root rot and will attract fungus gnats.
How to get rid of fungus gnats from succulents
The treatments you can choose from to eradicate fungus gnats range from simple home remedies to one that requires a trip to the store.
- Let the soil dry out
Before you take any other steps to get rid of the gnats, the first thing you need to do is allow the soil in the succulent’s pot to dry out.
As we mentioned above, gnats are attracted to the moisture in the soil around the plant. Refrain from watering the plant for several days until the soil is dry to the touch.
- Water and dish soap solution
One home remedy is a simple water and dish soap solution. The materials you need are already in your kitchen, so you will not need to leave the house.
This solution may not work as quickly as store-bought insecticides, but it is still an effective way to eradicate the gnats.
In a spray bottle, combine a quart of water with one tablespoon of mild dish soap. You now have a two percent solution that can effectively kill gnats.
If you are afraid that this solution might be too harsh for your succulent, you can do a test by spraying it on one leaf first and seeing if there are any negative effects after a few days.
Another natural way to kill fungus gnats is by using cinnamon. Cinnamon is a natural fungicide and will kill the fungus that the gnats’ larvae feed on.
Simply sprinkle the cinnamon until it covers the top of the soil; after a few days, you should see some results.
- Diatomaceous earth
Diatomaceous earth is just mineralized food dust that contains silica. It works by shredding insects when they come into contact with the substance.
You can either sprinkle it on top of the soil or mix it directly into the potting mix when you repot the infested plant.
The diatomaceous earth will not only kill the gnats themselves, but also the larvae in the soil.
Remember to wear a mask when handling diatomaceous earth.
An effective way of controlling gnats on your succulents is to introduce nematodes such as roundworms and eelworms.
These are microscopic worms that feed on fungus gnats while being completely harmless to both humans and succulents.
You could aso purchase indoor insect traps. These contraptions use ultraviolet light to attract the gnats, and then a fan sucks them into where a sticky glue board traps them.
These traps can be a bit expensive, but they work on many different insects and not only fungus gnats.
- Yellow sticky traps
A less expensive alternative to the ultraviolet light sticky trap is the conventional yellow sticky trap.
The bright color of the trap attracts the bugs and they will get stuck on the glue when they come into contact with it.
This is also a great non-toxic eradicator of fungus gnats. Simply stick the trap into the soil and wait for the gnats to trap themselves.
You can leave the trap near the plant until it gets completely covered with gnats before replacing it with a new one.
How to prevent fungus gnats from infesting your succulent
If you are properly watering your succulent, the risk of fungus gnats is actually quite low. If you allow the soil in the pot to dry out between waterings, the gnats will not have a conducive environment for breeding or laying their eggs.
Make sure that your potting mix is well-draining. You can check this by watering the plant and watching for the excess water to flow out of the drainage holes at the bottom of the pot: it should do so in a matter of seconds.
If your potting mix is too dense, you might have to replace it or add more grit to the mix, such as pumice or perlite. Also make sure the drainage holes at the bottom of the pot are sufficient.
Make sure the succulent gets the right amount of light. If you are keeping the plant in low light conditions, this only promotes fungal growth, hence providing the gnat larvae with an abundant food supply.
Light helps dry the potting mix out quickly and reduces the humidity around the succulent.
Yes, succulents attract fungus gnats, especially when the potting mix is constantly wet. Fungus gnats find the moist environment at the base of the succulent to be a great place to breed and lay their eggs.
Remove fungus gnats by letting the soil dry out completely, spraying the plant with a water and dish soap solution, sprinkling cinnamon or diatomaceous earth, or introducing nematodes and traps.
All of these methods are effective; you simply need to choose the one that works best for you. Repeat the treatment once a week for as long as needed until all the gnats have disappeared.
Image: istockphoto.com / kunphel