Pests are always a concern when it comes to the beauty and life of plants. Fungus gnats, although harmless to humans, are one pest that causes a lot of trouble for plant parents. These small gnats are about the size of fruit flies with the appearance of a mosquito and are notorious for planting eggs in houseplant soil.
Adult fungus gnats are mostly an annoyance, but the larvae may feed off organic matter in the soil and prevent your plant from flourishing. Once you get an infestation of fungus gnats, they are likely to stick around for a while. Make sure before all else to isolate your infected plant from others; it will be much more manageable to eliminate these pests from just one plant as opposed to a dozen! Here are some easy fixes to eliminate fungus gnats from your home.
Insect sprays are a reliable go-to solution for ridding unwanted company surrounding your plant. Make sure that the spray you choose is safe to use on plants – we want it to kill the pests, not the plant, too! This option from Grove uses biopesticides in place of chemical pesticides, making it safer for the environment, plant parents, and of course the plant itself. Because of this, it is safe to use on any plant including vegetables! As it is a concentrate, follow the instructions on the bottle to ensure proper dilution and usage.
Fungus gnats thrive off moisture, so one of your first steps should be to make sure your plant is not overly moist. By not overwatering your plants, you can make your plant uninhabitable for these pests and kill any larvae that are already living in the soil. A less obvious contributor to a moist setting around your plant in the water tray. Water trays are great at preventing an unwanted runoff mess in our homes, but they can also be attractive to pests like fungus gnats. Make sure to empty the tray regularly after watering to minimize the moisture surrounding your plant.
Neem oil is a great solution to try out, especially if you are a plant parent that may already have some around the house! This natural pesticide is popular for pest control in many houseplants and is definitely worth giving a shot to control fungus gnats. Try soaking the top few inches of your soil in neem oil to kill the larvae without causing harm to your plant.
Raw potatoes might just be able to save your plant from fungus gnat larvae! Chop up a raw potato into small ½-inch chunks and place them close to each other on the surface of your soil. The larvae should be attracted to the raw potato and make their way to the surface to eat it. After a few hours, you should find some larvae feeding on the underside of your potato slice! If your slice is completely covered, you know you have an intense infestation and you’ll need to replace and check on your slices more often. Keep chopping raw potatoes and disposing of them until the larvae are gone.
Sticky traps are an easy fix for fungus gnats along with any other similar-sized pests. These traps can be placed directly into the soil and as gnats fly around your plant, they will get stuck on the trap. The stickiness lasts for months and they are waterproof, so no need to worry about removing them for watering. Sticky traps are a great option for eliminating adult fungus gnats to prevent them from laying more eggs in the soil.
Top Dress Your Soil
Fungus gnat larvae tend to live in the top few inches of soil, so they are easy to target directly. A great way to stop adult gnats from interacting with the soil is by adding a layer of another medium atop your soil. There are a few different choices here, but sand seems to be a great option. Because of the size of each grain, the sand prevents adult fungus gnats from accessing the soil, eliminating the opportunity to lay eggs while still allowing watering to take place. Water can also easily pass through the sand to the soil to make sure your plant is still getting the love it needs. This method also keeps the larvae in the soil so they cannot escape as adult gnats. For this option, make sure the sand is covering all of the soil, from the roots to the edges of the pot, and is roughly ½ inch deep.
Apple Cider Vinegar
Another way to capture adult fungus gnats is with apple cider vinegar. In a shallow container, mix apple cider vinegar to attract the gnats with a couple of drops of dish soap to prevent the gnats from sitting on the surface of the vinegar. Cover this concoction with plastic wrap and create large enough holes for the gnats to fit through. Once they make their way past the plastic wrap, they will be unable to escape the liquid mix, preventing them from pestering your plants and laying more eggs.
This may sound like a ludicrous idea but trust us. Nematodes are tiny worms that, when placed in your infected soil, will quickly and effectively eradicate fungus gnat larvae. There are some technicalities as to the most effective way to inject the nematodes into your soil, but they typically are purchased in a solution that will need to be incorporated into the soil for best results. Fighting an insect infestation with another insect might sound counterintuitive, but this method has been successfully used for years!
Sources: https://www.bobvila.com/articles/how-to-get-rid-of-fungus-gnats/ https://www.smallfootprintfamily.com/how-to-control-fungus-gnats-organically#:~:text=control%20of%20them.-,Potato%20slices%20%E2%80%93%20Controls%20larvae,hours%20before%20looking%20under%20them. https://www.latimes.com/lifestyle/story/2021-07-14/how-to-get-rid-of-fungus-gnats-on-plants https://www.ortho.com/en-us/library/garden/how-kill-prevent-fungus-gnats