Pest Profile 2: Fungus gnats

Fungus gnats are unsavoury flying pests which aren’t all that harmful, but they can still be a bit of a headache. Nobody likes seeing tiny little flies flitting around their homes searching for soil to make their home in. In this post, we’ll be delving into how to identify, exterminate and prevent fungus gnat infestations.


Fungus gnats are fairly easy to to identify: they’re little flies that look like tiny mosquitoes. They fly fairly slowly and lay their larvae in moist soil. Their larvae are barely visible, clear worms. I wouldn’t bother trying to find them, because adult fungus gnats are so much easier to find, and their presence tends to indicate the presence of larvae.

There will not be any visible signs of infestation in your plants. This is because fungus gnats only very rarely feed on the roots of plants. They will only do so when there is no fungus, algae or decaying plant matter to feed on, which is very rare. In fact, fungus gnats are more of a nuisance in that they’re unsightly, and aren’t all that harmful to plants. In fact, some might even say that they might be beneficial in that they feed on fungi and algae, which can compete with plants for nutrients. However, both the benefits and the drawbacks of fungus gnats for houseplants are greatly attenuated by how little they eat. Either way, you won’t notice much of a difference. They’re just unsightly to look at.

fungus gnat


Fungus gnats are extremely hard to completely exterminate, but they can be controlled. In light of this, it’s a good thing that they’re fairly harmless.

If you want to get close to complete fungus gnat extermination, you’ll need to take a two-pronged attack on them. First, you’ll need to reduce moisture in the soil. This retards the growth of algae and fungus, eliminating fungus gnats’ food source. Dry soil also causes fungus gnat eggs to dry out and die. The problem with this method is that it requires your plants to withstand dryness for longer than the fungus gnats, which is not great for some plants, like ferns. Also, if you have multiple plants held together on different watering schedules, then fungus gnats can just migrate from dry soil to the wet soil in a more recently watered plant.

This is why you should also employ yellow sticky traps. Different traps will have different instructions, so make sure you read the packaging. Basically, they’re traps that trap fungus gnats on them, stopping them from getting into the soil and laying eggs. They will nto catch all fungus gnats, but they’ll certainly help in controlling the amount of fungus gnats in your soil. If you employ both methods of controlling fungus gnat infestations, you’ll get quite close to total extermination.


Prevention is the best method of dealing with fungus gnats, and certainly the most humane. If I’m going to be completely honest, I just let them be because I feel bad about killing them, because they’re almost completely harmless.

Prevent infestations by choosing potting mixes carefully. Read reviews on the potting soil beforehand to see if others have had bad experiences with it, where it came with fungus gnat eggs already in the potting mix. This is one of the main ways fungus gnats enter homes.

Also prevent their presence and infestation by making sure conditions aren’t ideal for their survival. Try not to keep soil constantly moist, and make sure you allow soil to dry out between watering.

Some people like to put their plants outside in the summer to promote growth, but the trade-off is that fungus gnats and other pests are often brought into the home as a result. I prefer to keep my plants indoors in the summer for that specific reason.

I hope you guys learned something from this post, and good luck with your fungus gnats if you have any 🙂

Published by plantboye

Tech illiterate and pretending to be proud of it.

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