Plants 101

Bug Off: All About Fungus Gnats

If you noticed some bugs around your plant, chances are you want to get rid of them. You’re in luck. Our Bug Off series takes a closer look at common houseplant pests, how to get rid of them and how to prevent future breakouts.

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Why Does My Plant Have Pests?

It’s important to note that bugs are totally normal. They are not a sign of poor hygiene or lack of care on your part. You’re doing fine. It’s just nature taking its course. Bugs can remain invisible to us, even when we inspect our plants before purchasing. You may want to spray your plants with a mild, unscented soap-based cleanser, neem oil, or insecticidal soap to kill any pests that may be hiding. Check in on plants from time to time for pests and make sure they aren’t under stress, lacking light, have too much water or not enough, and that the humidity levels are ideal — any one of these or a combination of factors can be the perfect mix for pests to emerge.

What Are Fungus Gnats?

Tiny bugs that look like fruit flies. They seem to come out of nowhere and all at once. As grubby larvae, fungus gnats eat the fungi that lives in your soil. Fungus gnats love moist soil because that’s where fungus grows. Since there’s an abundant food source, fungus gnats will breed and make your plant their new home.

Adult fungus gnats who have wings but prefer to walk, hardly feed on fungus at all. In small numbers, fungus gnats are pretty harmless to your plant and have no interest in you or your pets. Aside from being flat out annoying, fungus gnats do all sorts of unpleasant things, like spreading pathogen spores, transferring from infected tissues to non-infected tissues and after they’ve eaten all the fungus they may start feeding on the roots of your plant.

Getting Rid of Fungus Gnats

If you have fungus gnats, you may be overwatering or not allowing your soil to dry out properly between waterings. Remember, moist soil means more fungus and more food for fungus gnats. Try watering less and letting the soil dry out. Adding a 2 inch layer of horticultural sand as a top dressing layer will also help to prevent adult fungus gnats from laying eggs within the soil.

You can also try incorporating Mosquito bits into your waterings which is a natural larvicide that kills the larvae of flying insects- like fungus gnats! The most effective way is to add the bits into your plants water, letting it soak for 20 mins which releases the bacterium. From there, you can give your plants a thorough watering and the larvicide will kill the larvae upon feeding! This is one of the most effective ways to control gnat infestation as it targets the pest at the stage it feeds the longest in its lifecycle!

Bugs are totally normal. They are not a sign of poor hygiene or lack of care on your part. You’re doing fine!

Nematodes are another way to control gnats. They attack the larvae and can live longer in the soil. This is not a long-term solution though, for the simple fact that nematodes are living creatures and will eventually die.

Sticky traps may also work. Adults fungus gnats are attracted to the color yellow and that’s the color sticky traps happen to be. Note that some adults may have already laid their eggs before becoming stuck to the trap, and more gnats may be hatching soon.

Plant pests are annoying but harmless to humans and pets. They are relatively easy to be rid of with a few simple solutions. When treating your plant for pests, be sure to give them time to recover. Be sure to check out our articles on how to get rid of mealybugs, spider mites, and scale.


Words By The Sill

Empowering all people to be plant people — a collection of articles from The Sill’s team of Plant Experts across a variety of plant care topics to inspire confidence in the next generation of plant parents. Welcome to Plant Parenthood™.