To kill fungus gnats naturally, use BTI. Fungus gnats are closely related to mosquitoes, so fungus gnat larvae are effectively killed by BTI. (BTI is a naturally occurring bacterium that is deadly to mosquito larvae AND fungus gnat larvae.) Sprinkle Mosquito Bits on top of the soil of an infested plant. When you water the plant, the water will release the active ingredient in the bits into the soil, killing the eggs and larvae. Each time you water your plant, more of the Mosquito Bits will seep into the soil. Repeat this for at least three waterings, or until the fungus gnats are gone. Having Mosquito Bits on top the soil acts as a top-dressing that also helps deter adult fungus gnats from laying their eggs in the soil.

If these cheaper, natural methods still haven’t managed to rid you of your gnat infestation, then you can escalate things with these more powerful gnat killers. Hydrogen Peroxide Important! Let the topsoil dry out between waterings. Fungus gnats usually result from over-watering.

Plant Symptoms

As an alternative to using Mosquito Bits, systemic insecticide granules are also helpful in the control of fungus gnats. Add the granules into the soil and water them in. The pesticide will be absorbed into the roots of your plants, killing the larvae that feed on the roots. Interestingly enough, a common household item is one of the top recommendations that I have for controlling these pests. Hydrogen peroxide (the standard 3% topical variety) can be used as a soil drench. Water your plants with a small amount of water to moisten the soil (so it is ready to absorb the nematodes);

There are six different families of insects that make up the broader category of fungus gnats. These include the Sciaridae, Mycetophilidae, Ditomyiidae, Bolitophilidae, Diadocidiidae, and Keroplatidae. Most fungus gnat species are not harmful to our gardens, but the dangerous ones are in the Sciaridae family, especially those in the Orfelia and Bradysia species. Now stir or shake the water to make sure the BTI is thoroughly mixed in. Then use the “BTI tea” to water the soil or potting mix of houseplants and container plants. This treatment controls fungus gnat larvae present in the soil at the time of application. For best results, use your Mosquito Bits/BTI tea solution within 48 hours. Beneficial nematodes are a microscopic organism that feeds on the larvae of fungus gnats. It is delivered to you in a dormant, refrigerated form that looks like a powder. They are not harmful to humans. There are some home remedies which I haven’t tried so I can’t speak to their effectiveness, but here are two very effective methods to kill fungus gnat larvae in your potting mix. One is a biological control, and the other is a systemic pesticide. BIOLOGICAL CONTROLOne recommendation to soak mosquito bits in water (2 tablespoons of mosquito bits to a half-gallon of water). Then you can water your plants with the mosquito bit-soaked water once per week for three weeks. A Fungus gnat-killing product – Either a wide spectrum insect killer or something with BT like crushed-up mosquito bits mixed with water in a mister or used to water your plant. If the fungus gnat infestation gets out of hand, even adult cannabis plants start looking unhealthy, showing many symptoms such as wilting, yellowing, drooping, spots

Adult fungus gnats do not eat; their only purpose is reproduction. Over the course of her short lifespan, a female fungus gnat can lay 100 to 200+ eggs. A female gnat will deposit up to 40 eggs at a time on the surface of moist soil, near decaying organic matter, or hidden closer to the stem of a plant. Cannabis roots are not the main source of food for fungus gnat larvae, but roots get caught in the crossfire. Although the main diet of fungus gnats is fungus and decaying matter, the larvae happily gnaw on root hairs and young tender roots of cannabis plants. Damping off” – seeds or seedlings are weak for no apparent reason; sometimes stems weaken and seedlings can even just fall over and die This was one of the most popular remedies touted by gardeners on internet forums, so I approached this method with high hopes! Chamomile and cinnamon are powerful natural fungicides, so the logic was that by killing off the gnats’ primary food source, it makes your plant soil less

Once both the adults and larvae are under control, then you can put measures into place to help prevent fungus gnats from reoccurring in the future.