Dealing with Fungus Gnats? A few simple solutions should make things a little less ‘sticky’.
How to Deal with Fungus Gnats
By Julie Stoyka
I have had three “infestions” of fungus gnats in the last ten years. The first happened during late spring, so I simply shoved my plants out the door and let nature take care of the problem. The second affected one plant (thankfully only one) but was resolved within a month using the sticky trap method. The third is currently raging through my office!
This year, while I have no gnats at home, my two office plants (pilea and pothos) had a legion of fungus gnats take over! I have no idea how because the soil and the plants came from home, where I have yet to see one gnat.
The good news is that fungus gnats are more annoying than lethal. They are fruit-fly sized but don’t bite or sting, so they really only pose a choking hazard…if you happen to inhale while swatting them away! Ultimately, they don’t really harm your plant at all; at least above the soil.
Beneath the soil, the young larvae can damage roots so it is important to get rid of them as soon as you can.
There are a variety of ways to deal with gnats but for me, the best (and most disgusting) method is to use sticky traps. I don’t go in for the pretty little flower spikes (but hey…each to their own); instead, I unroll a sticky trap and simply shove it into the soil. Occasionally a leaf or two get a little sticky but the system works pretty well!
To the left is the sticky trap I set up 2 weeks ago…and I figure that I will need to keep setting them for another two to three weeks to ensure I hit the full life cycle of gnat. Yes, it’s unappealing but it does work.
Here are a few other suggestions:
1. Don’t overwater.
2. Keep the top layer of soil dry in between watering.
3. Cover the top layer with sand, vermiculite or decorative stone to prevent eggs from being laid in the first place.
4. Other people swear by nematodes and mosquito bits.
5. A 4:1 hydrogen to water mix sprayed on the soil is supposed to kill the larvae without damaging the roots.
And, if none of these work – simply repot the plant in new soil. You should now by 4 weeks in if things are that dire! There is also a great article from the L.A. Times all about getting rid of these pesky little gnats: https://www.latimes.com/lifestyle/story/2021-07-14/how-to-get-rid-of-fungus-gnats-on-plants