Gnats on Succulents

Gnats on Succulents

Caring for succulents is usually easy and fuss-free as long as you provide them with enough sunlight, fast-draining soil, and just the right amount of water or moisture. However, it can be devastating when they are infested with pests and insects. In this article, get to know in-depth details on one of the succulents’ mortal enemies: the fungus gnats.

Gnats on succulents: What are they?

Fungus gnats are insects that belong to the fly family Diptera. These insects resemble small mosquitoes and thrive on damp and decaying algae, fungi, and vegetation. They may appear in large swarms and pose problems to nurseries and greenhouses. They live on soil and containers where the larvae feed on roots, root hairs, and organic matter. 

Gnats are a nuisance for succulents because they consume the sap or juice of the leaves. They tend to stunt plant growth and make the leaves turn yellow and eventually fall off. Larvae damage nurseries and gardens since they harm seedlings, cuttings, and young plants. They may also spread plant pathogens and disease among flowering plants and crops. 

These pests are carriers of plant fungal diseases like black root rot, Verticillium wilt, and Fusarium wilt.  They are sometimes confused with black flies, moth flies, or March flies. Adults are dark and delicate-looking with slender legs and segmented antennae. They are usually about 1/8 to 1/16 inches long with light gray to transparent wings.

How can I prevent gnats on succulents?

Here are some ideas to prevent gnats on your succulents:

1. Make sure your plants are in fast-draining soil. 

Moist soil is a big attractant for pests like fungus gnats, so keep the soil beneath the plants fast-draining. If your succulents are in pots, water should come out of the bottom of the pots within seconds of watering them. If that is not the case, add more grit to the soil, such as pumice or perlite. 

2. Place plants in areas with bright light. 

Sunlight helps evaporate excess water and moisture quickly.  Also, humidity keeps the soil moist, which explains why succulents thrive more in environments with dry air. 

3. Add top dressing to the pots. 

Top dressing like pebbles and decorative gravel enhances the look of succulents. It also protects the plants from stagnant water and rot, which attract gnats. 

Treatments for Gnats on Succulents 

These are the common treatments for gnats on succulents:

Dry out the soil. 

Try to wait an extra four or five days after you water your succulents before the next watering. Fungus gnat larvae cannot live in dry soil for a long period, so extending the time between waterings can wipe out these flies. 

Use a dish soap and water solution.

Combine dish soap with water and spray the mixture into the soil of the affected plants.  Repeat until you cannot see any signs of gnats. The soap and water mixture poisons the pests and prevents them from infesting the plants. 

Use hydrogen peroxide. 

Hydrogen peroxide is an effective anti-bacterial, anti-fungal, and anti-bug ingredient. It breaks down simple water and oxygen, which makes it environmentally safe.  Use a 10% solution for killing gnats and a 3% solution to treat fungal infections in plants.  

It is safe for plants up to a maximum of 30% strength, and can be applied on leaves, stems, and roots. It can also be placed liberally into the soil. Repeat the treatment until there are no signs of the pests. 

Try cinnamon. 

Most plant growers find cinnamon moderately effective in treating pests and other garden issues. It is a deterrent for pests and fungi. Sprinkle it liberally on the soil around the base of the plant and dampen it slightly by spraying some water to mix it in. 

Use diatomaceous earth. 

Food grade diatomaceous earth, or DE, is commonly used to treat pests like gnats. DE is lethal to pests as it gets between the joints of their exoskeletons and shreds them from the inside. Simply sprinkle it on top of the soil. It will slowly kill adult gnats that lay eggs as well as the larvae. 

Aside from these treatment options, some plant owners also swear by the effectiveness of rubbing alcohol solution or pure neem oil. Simply spray them in certain plant parts regularly to get rid of the pests. 

Other pests that ravage succulents, aside from gnats, include the following:

  • Mealybugs
  • Scale 
  • Aphids 
  • Spider mites 
  • Whiteflies
  • Ants 


Gnats on succulents are an eyesore and can cause irreparable damage. These mosquito-like pests consume the sap of succulent leaves and are also known as carriers of fungal diseases like black root rot.

Eradicate these little pests and prevent them from causing damage to your succulents by spraying them with a dish soap and water solution, applying hydrogen peroxide,  or sprinkling cinnamon. You can prevent them from infesting your plants by placing your succulents in fast-draining soil, putting them in bright light, and adding a top dressing like pebbles.

Image: / Marc Leupold