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Fungus Gnats: The Most Dreaded Indoor Pest

The Most Common Indoor Pest Is FUNGUS GNATS!

What Are Fungus Gnats?

Fungus Gnat Pest Control

Fungus Gnats or sciarid flies are the bane of most indoor gardeners. The tiny (2mm or less), mosquito-like pests hover in small groups above the soil of your indoor plants.

These adult gnats are annoying and an eyesore but do not cause much harm. On the other hand, it is the larvae in the root zone that cause the most damage to the plant.

Although they primarily feed on fungi and decomposing organic matter, they often eat the tender root system. They target feeder roots and can even bore into the stem.

Left unchecked, these pests can cause all sorts of problems including loss of vigor, yellowing, wilting, and spotting. Often these symptoms are mistaken for a nutrient deficiency or ph problem. In addition, they can carry and transmit diseases and pathogens like pythium.  Cuttings, seedlings, and saplings may even die due to severe infestations.

Where Do They Come From?

They can come into the home through newly purchased plants, potting mix, and organic medium like coco coir.

It is always good to check for little tiny maggot-like larvae in the topsoil of the plant at the nursery before you purchase.

However, it’s not feasible to check every bag of soil or organics like compost or cocopeat. It is even harder to spot the eggs so even with the most diligence, you will probably still get these pesky little buggers.

Fungus GnatsFungus Gnat Life Cycle

Eggs hatch within 3 days, with warm conditions speeding this up. The larval stage lasts around 10 days before it changes into pupae.

Adult fungus gnats emerge 4 days later and live for about a week. During this time, they can lay upwards of 300 eggs.

Due to the short gestation period, these pests can become a major problem in a very short amount of time.

How Do I Get Rid Of Fungus Gnats?

The flying adults are annoying but not too damaging so controlling them is mostly for aesthetics. We recommend sticky traps as a cheap and effective way to do this.

It is much more efficient to target these pests during the larval stage as they spend most of their lives in this form and do the most harm. Thankfully as the larvae live in the topsoil, they are very easy to control and even eradicate.

  1. Fungus gnats thrive in wet and humid conditions. Be careful not overwater and ensure you have adequate drainage.
  2. Isolate infested plants so the pesky gnats don’t spread to other plants.
  3. It is recommended to let the topsoil dry out between waterings.
  4. If you still have fungus gnats then see below for our Top 3 Products to Treat Fungus Gnats:

DE-GNAT All-natural Diatomaceous Earth (DE)

Fungus Gnat eggs are always laid in the soil. By adding a 1-3cm solid layer of DE, you are creating a barrier that the gnats have to pass thru once they have hatched. This first dries the insect exoskeleton out then kills them through its extreme abrasive properties. Most importantly, this stops the adults from being able to get back down into the topsoil to lay eggs. This breaks the cycle!


De-Gnat Insect Shield 1L Fungus Gnat Sciarid Fly

CX Tanlin Drops

Our best-selling treatment for fungus gnats. This product is a non-toxic, plant, pet, and human-safe soil drench. Very easy to use, just mix 1 drop per liter of water. Make sure you get good coverage on all the soil. This is good to use every water until the gnats have disappeared and then monthly as maintenance.


Tanlin Drops to treat Gnat Fungus

Scarid 10

We only recommend using this as a last resort for extreme infestations. Mix 30ml per Litre of water and spray on the surface of the soil once a week avoiding contact with plants. Please be careful as this is a rated insecticide.


Sciarid 10 to treat Gnat Fungus and Sciarid Flies


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