Had to look that plant up!
And, here are some other fungus gnat solutions...
Sand – Controls larvae
Adults lay their eggs in the top 1/4 inch of moist soil. If you dress the top of your soil with a 1/4–1/2 inch of sand, it will drain quickly and often confuse the adults into thinking the soil is dry. You can use colorful decorator sand and have fun with this!
Vinegar – Control adults
A good trap for both fungus gnats, and especially fruit flies is to put out baby food jars filled halfway with apple cider vinegar or cheap beer with a couple drops of dish soap added to break the surface tension. Once you’ve filled the jars, screw on the lids, and poke several holes into them large enough for fungus gnats to enter.
Place these jars in areas where you are having problems with either fungus gnats or fruit flies, and they will dive into the vinegar and drown. Strain and re use the vinegar until you have gained control of them.
Potato slices – Controls larvae
Slice raw potatoes into 1-inch by 1-inch by 1/4-inch pieces. Place the slices next to each other on the surface of your potting media to attract fungus gnat larvae. Leave the potato slices in place for at least 4 hours before looking under them. (Be prepared to be grossed out a bit.)
Once you have seen just how bad the problem is, replace the potato slices every day or two to catch and dispose of as many larvae as you can, and consider adding additional control measures.
Sticky Traps – Controls adults very effectively
Make your own sticky trap by smearing Vaseline or Tangle foot on a 4″x6″ piece of bright yellow cardstock, and place the card horizontally just above the surface of your potting media, where it will catch the adults as they leap from the soil. Set another trap vertically to catch incoming gnats, whiteflies, thrips, and more.
Food Grade Diatomaceous Earth – Controls larvae
Food grade diatomaceous earth is another effective treatment for fungus gnats. Diatomaceous earth (DE) is mineralized fossil dust that is both natural and non-toxic to the environment. Make sure you get food grade diatomaceous earth—not pool grade, which is not pure enough for use around food gardens and pets.
Always wear a simple dust mask when working with DE: Inhaling any kind of dust is never a good idea.
DE contains microscopic shards of silica that physically shred any insect that walks through them, therefore it will not work in hydroponic gardens. But if you mix some into the top layer of infested soil—or better yet, into your potting mix before planting—it will kill any gnat larvae (and adults) that come in contact with it, as if they were crawling through crushed glass.
DE works the same way to kill fleas, bedbugs, slugs and other insects too, so don’t use DE to control fungus gnats in your worm bins. (Poor worms!) Some people eat DE therapeutically to kill intestinal parasites.
Hydrogen Peroxide – Controls larvae
Mix one part 3% hydrogen peroxide with four parts water. Allow the top layer of your soil to dry, and then water your plants with this solution as you normally would. The soil will fizz for a few minutes after application; this is normal.
The fungus gnat larvae will die on contact with the hydrogen peroxide. After a few minutes the fizzing stops and the peroxide breaks down into harmless oxygen and water molecules. Repeat as needed.
Chamomile Tea – Controls dampingoff
Weak chamomile tea (after it has cooled) is another natural fungicide that is effective in stopping damping off, though it does not treat fungus gnats at all. Simply brew a quart of strong tea, let it cool, and add it to your 1-gallon watering can. Add more water to the can until full, and use whenever you water.
Cinnamon – Controls larvae and damping off
Cinnamon powder is a natural fungicide that has been shown to be particularly effective against damping-off. It helps control fungus gnats by destroying the fungus that the larvae feed on. Only true Ceylon cinnamon, or Cinnamomum verum, will work.
Simply sprinkle enough cinnamon to form a visible layer across the top of your potting media, and repeat every few weeks, if needed. DO NOT use to control fungus gnats in worm bins as cinnamon will kill your worms.
BT – Bacillus thuringiensis var. israelensis – Controls larvae very effectively
Bacillus thuringiensis (Bt) is a naturally-occuring bacteria that kills many types of worms, caterpillars, larvae and insects. There are specific strains of Bt called “israelensis” or “H-14” that specifically kill fungus gnat larvae. (Othervarieties of Bt will not work for fungus gnats.)
Used extensively in organic greenhouses, Bt-I can work to stop fungus gnats where nothing else will, though it is a little pricey. Bt-I is safe for use in worm bins, and can help control mosquito larvae too.
Beneficial Nematodes – Controls larvae
There is a type of nematode, Steinernema feltiae, that can be used to drench the soil each time you water. These tiny worm-like creatures will enter the larvae of soil pests like the fungus gnat and release a bacterium which is lethal to it.
Nematodes are expensive, and are best used on a large infestation of many plants, because they are hard to control in small quantities. Nematodes kill a variety of soil-borne pests, and are safe for use in worm bins, too.