Does Neem Oil Kill Fungus Gnats? Spray, Soil Soak, Neem Cake

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Quite a few common plant pests find their way indoors. Few are as annoying and destructive as house fungus gnats.

These tiny insects, also known as “fungus flies,” resemble mosquitoes but are poor fliers and won’t attack humans. Instead, they get their name from a diet of fungus, leaves, and decaying organic matter, making your houseplants so attractive to them.

Yellow sticky tape full of fungus gnatsPin
Indoor plant with fungus gnats | schlosann-DepositPhotos

Before you ask, “Will Neem Oil Kill Fungus Gnats?” the answer is yes!

Fungus gnats only live for about a week once they reach adulthood. But it isn’t the adult gnats that are the concern.

A single female can lay up to 300 eggs! They hatch into gnat larvae with voracious appetites and can harm seedlings and chew up a plant’s root system.

These pests, part of the Psychodidae family, feed on compost, mulch, and other things your plant may also need, and it’s not always possible to remove any decaying organic matter.

Instead, indoor plant enthusiasts have been turning to neem oil as their crucial remedy against the frustrating gnat pest.

In this article, we’ll look in-depth at neem oil and fungus gnats, including using neem oil for gnats.

How To Use Neem Oil For Fungus Gnats Control

Neem oil is a non-toxic, all-natural pesticide with insecticidal properties that kill many pests on contact and help you get rid of gnats.

To deal with the particular fungus gnat threat, a neem soil soak or neem cakes are perhaps the best remedies out there.

Neem oil, fungus gnats, small green bottle, wooden surface.Pin

What Is Neem Oil?

Many people ask “What is Neem Oil?” Neem is the MacGyver of the plant care world and is available in a crude (or raw), clarified hydrophobic, or cake form. The oil is made by crushing the seeds of the Azadirachta indica tree.

Azadirachtin has a chemical composition like that of key insect hormones. A harmful pest that ingests it may stop eating, fail to reach the next developmental level or be unable to lay eggs.

Raw neem oil is most effective when cold-pressed, as it loses potency in heat. The resulting solids are neem cakes.

Neem cakes contain trace amounts of Azadirachtin and are often used to supplement or replace compost due to their rich organic content.

Raw neem oil can be further processed to remove the Azadirachtin, leaving clarified hydrophobic neem oil behind.

The processed form of Neem Oil has trace amounts of Azadirachtin. It is usually sold in concentrations of .5% – 2% percent and is the primary ingredient in most commercial neem oil foliar sprays.

It can clog the airways of any insects it comes in contact with, suffocating them. It is also a powerful contact fungicide, which contributes to systemic houseplant insect control.

Related: Does Diatomaceous Earth Control Fungus Gnats?

Neem Oil Soil Drench For Fungus Gnats

The soil soak application method is what it sounds like – a diluted mixture of crude neem oil that’s poured over the soil and absorbed by the plant’s roots.

Making a neem soil drench is simple and has a shelf life of about four days but an active life of up to 22 days once applied.

How To Use A Neem Oil Drench For Fungus Gnats

  • Gently stir 1 teaspoon Dawn dish detergent into a gallon of water to serve as an emulsifier (i.e., it allows the oil and water to mix).
  • Add 2 tablespoons of 100% percent cold-pressed raw neem oil.
  • Pour 2 – 4 cups of the mix directly onto the potting mix in your containers when it’s time for the next watering.
  • Make sure to test with a tiny amount a day beforehand to ensure the plant has no adverse reactions.

Azadirachtin is a powerful systemic insecticide that kills grubs beneath the soil and is absorbed by the roots.

Does the drench of Neem Oil kill gnats? Yes, and over the next three weeks, any fungus gnats unlucky enough to bite into the plant will ingest the toxin.

The drench Neem treatment won’t harm your children or pets. It is safe for plants and used as a preventative once you eradicate the initial infestation.

Using Neem Cake For Fungus Gnats

The creation of neem oil leaves behind no waste. Investing in a few neem cakes is an excellent way to treat any houseplants that need a lot of organic matter.

Break up the Neem cakes and add them to new potting soil or gently mix them into the top layer of a container’s existing soil. The application of Neem cakes provides effective control for fungus gnats on plants.

Adult and larval fungus gnats will consume the Azadirachtin in the compost as they attempt to eat the seed solids.

The plant may absorb the Azadirachtin during watering, giving it a little extra anti-pest boost.

How To Use Neem Oil For Fungus Gnats: A Note On Foliar Sprays

When fungus gnats are attracted to plant fungal infections, foliar sprays are a good choice. But you must make sure the gnats come in direct contact with the spray to kill them.

The spray’s clear oil goes away in roughly 45 minutes to an hour and doesn’t leave any stains.

If you choose to use it to combat fungus, we suggest picking up an all-natural spray, such as Bonide Ready to Use Fungus Gnat Neem Oil Spray.

Neem Oil and Gnats FAQs

How Long Does It Take For Neem Oil To Kill Gnats?

Neem oil can kill gnats within 24 hours of contact. It may take several days to kill a gnat infestation, according to the University of California-Riverside.

How Does Neem Oil Kill Fungus Gnats?

Neem oil kills fungus gnats working as a biological control by disrupting their hormonal balance, interfering with their reproductive cycle, and inhibiting their ability to feed. (Source)

How To Use Neem Oil On Houseplants For Fungus Gnats?

Here is how to use neem oil on houseplants with fungus gnats:

  • Mix one tablespoon of neem oil
  • One gallon of water
  • Apply the solution to the soil of the affected plants and spray all the foliage and the undersides of the leaves.
  • Repeat every seven to 14 days until the infestation is gone.

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