Andre CampbellAn infestation of fungus gnat larvae can cause damage to certain plants by feeding on their roots. Fungus gnats are small, gray to black flies that mostly affect indoor houseplants.
The adult gnats do not cause damage to plants; however, they can be annoying as they tend to fly around your potted houseplants when watering them. These pests are destructive at the larval stage [1].
How to Get Rid of Fungus Gnats Naturally
Below are some of the most common home remedies and natural control methods for controlling fungus gnats.
1. Sticky Traps
Fungus gnats deposit their eggs in the soil. Therefore, to catch the adults before they lay eggs, put the traps on the soil surface.
These mosquito-like insects are attracted to the color yellow, so they will easily get caught on yellow sticky traps. You can also hang the traps close to plants in nurseries or indoors to catch new adult gnats flying in.
2. Diatomaceous Earth
This product is great for getting rid of fungus gnats in the house. Diatomaceous earth will cut through the larvae and adult pests, dehydrating and killing them.
Therefore, mix it in with potting soil or sprinkle it onto the top layer of the soil.
3. Vinegar
You can use vinegar to help control fruit flies as well as adult gnats.
Pour some apple cider or white vinegar into a shallow bowl and add a little liquid dish soap. Next, place the bowl near the affected plant.
The pests love the smell of vinegar and will enter the bowl for it. But they’ll fall in and drown, thanks to the dish soap.
Continue this home remedy until the infestation is under control.
4. Bacillus thuringiensis israelensis (Bti)
This is a bacterium naturally occurring in the soil [2]. BTi produces a protein that is toxic to gnat worms, mosquitoes, and certain other pests once ingested.
Following the product instructions, water the soil with the solution to kill fungus gnat larvae. You can also use it to get rid of mosquito larvae.
5. Beneficial Nematodes
You can also purchase beneficial nematodes and apply them to the soil. They will hunt down and parasitize fungus gnat larvae in the soil.
6. Raw Potato
You can also use sliced potatoes for controlling fungus gnats by removing their larvae.
Slice raw potatoes into chunks and place them on the soil surface. The potato will lure away gnat larvae from your plants.
After a few days dispose of the infested potato chunks. Repeat the process with fresh potato chunks.
7. Hydrogen Peroxide
The value of this common household product is that it can kill fungus gnat larvae on contact. Moreover, it can eliminate the pest at all stages of its life cycle—eggs and adult gnats too.
To use hydrogen peroxide for fungus gnats, mix one part hydrogen peroxide (3%) with four parts water. Leave the soil to dry out a little, then use the solution to water your plants.
Also, lightly spray the leaves and stems of plants. This DIY gnat spray will not harm your plants.
8. Cinnamon
This is a very unique fungus gnat home remedy. It is unique because it kills the fungus spores that the gnats feed on.
To use cinnamon for fungus gnats, spread a thick layer of the powder over the surface of the soil. Repeat every few weeks.
9. Sand
Fungus gnats like damp soil in order to lay their eggs. However, a layer of sand on the soil surface will dry out the soil quickly.
This discourages soil gnats from laying their eggs there.
10. Soapy Water
Apllied properly, soapy water can suffocate and kill fungus gnats and their larvae.
Therefore, use a little liquid soap and water to make a homemade spray for fungus gnats. Do so by combining one tablespoon of liquid soap with a quart of water.
Spray this soapy water solution on plants and soil.
11. Keep the Soil Dry
One of the first lines of attack against these pests is to create an inhospitable environment so they lack what they need to thrive.
So, keep the top level of the soil dry. This will deter the adult gnats from laying their eggs there. Preventing the soil from getting excess moisture is always helpful in controlling these pests.
12. Molt-X
This commercial product is a botanical pesticide that contains azadirachtin.
Molt-X works by preventing insect molting and inhibiting feeding. It also acts as a pest repellent.
Apply this treatment as a foliar spray to kill fungus gnats. You can also use it as a soil drench.
13. Azera Gardening
This product is another organic insecticide containing Azadirachtin from neem seeds. It also contains pyrethrins derived from some chrysanthemum flowers.
These two ingredients act as powerful botanical pesticides that help control a wide variety of pests, including garden gnats. Apply Azera Gardening to your plants as per the product application instructions.
14. Bug Buster-O
Monterey Bug Buster-O is also an organic insecticide that quickly kills fungus gnats and other pests. Dilute according to the product instructions and spray at the first sign of plant gnats.
Aim the spray at the flying adult gnats. Spray around plants and seedlings to kill others and destroy larvae.
However, be careful not to spray near bees outside because it is toxic to them.
15. Melissa Oil
This oil is also known as lemon balm oil. Many insect pests like deer flies, fungus gnats, and horse flies are attracted to Melissa oil.
So, if you are seeing signs of fungus gnats around, a few drops of Melissa oil added to sticky traps will invite these flies to your trap.
Remove this homemade fungus gnat trap and set a new one frequently.
16. Organocide
Organocide is a 3-in-1 spray that is effective against many soft-bodied insects.
You can use it as a fungus gnat treatment to spray the leaves and stems of your plants. It is also great for indoor and outdoor use.
17. Neem Oil
Neem oil is a powerful organic solution used to control many garden pests.
To use neem oil for fungus gnats, combine one teaspoon of organic liquid soap with one tablespoon of neem oil and a liter of warm water. Shake well.
Finally, soak the soil and spray your plants with the solution. Repeat as necessary.
Takeaway
Plants particularly susceptible to attack by fungus gnats include geraniums, African violets, poinsettias, and carnations. However, many other indoor and greenhouse plants can get affected.
The most important action to take to keep these pests at bay is to keep the soil dry to slow down or stop an infestation. Additionally, adding one or more of the above natural remedies will help eliminate the problem.
Sasha Campbell
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