The Ultimate Guide: How To Get Rid Of Fungus Gnats
What Are These Small Black Flies In My House?
If you're seeing small black flies in your houseplants, the chances are, they're fungus gnats. If you're wondering what fungus gnats look like, they're very small black flies that're slightly larger than a fruit fly, congregating around windows and plants, instead of food or sinks.
You may have been sipping a drink, when a flying insect hit you in the face. You may have tried to swat it away, only for it to keep coming back, relentlessly. Maybe you became irritated as you watched the gnat fly head first into your drink, wondering how the creature thought that was sensible
Ahh, the fungus gnat. Always around when you're relaxing, always around when there's food. You may have inhaled one in-between words, or you may have inhaled them through your nose. Lovely.
Enough jesting. Fungus gnats are no laughing matter. An infestation soon becomes irritating, and you'd do anything to get rid of them. Let's use that motivation and get rid of gnats in your house for once and for all. Our comprehensive fungus gnat guide covers every single method known to kill them, why they're there, and how to prevent them from coming back.
What Attracts Fungus Gnats?
If you're wondering why there's fungus gnats in your house, you've hit the right section. Let's explore the things that release a scent of decaying matter, which attracts fungus gnats into our homes:
Moist Soil: Fungus gnats are drawn to moist soil, particularly when it remains consistently damp. Overwatering plants creates an ideal breeding ground for these pests. Allow plants to thoroughly dry out between watering.
Decaying Organic Matter: Organic material such as decomposing leaves, roots, and other plant debris provides food for fungus gnat larvae, and the smell attracts the adults. This is found in potting soil, compost, and mulch.
Fungi: Fungus gnats feed on fungi, hence their name. Fungus thrives in moist, decomposing organic matter, making it attractive to fungus gnats.
Indoor Plants: Houseplants, especially those with damp soil or that have accumulated dead plant matter, can attract fungus gnats. Potted plants provide a controlled, moist environment ideal for their life cycle. Poor drainage in pots can lead to waterlogged soil, attracting fungus gnats.
Standing Water: Standing water in saucers under plant pots, overwatered gardens, or poorly draining areas can attract fungus gnats, providing a moist environment for egg-laying. Check and empty catch trays regularly.
Humid Environments: High humidity levels can contribute to the attractiveness of an area for fungus gnats, as it helps maintain the moist conditions they prefer, and contributes to fungal growth.
Overripe Fruits and Veg: Overripe or rotting fruits and veg attract gnats.
Where Do Fungus Gnats Come From?
If you're wondering how fungus gnats got in your house, you wouldn't be alone, as that's a question almost all plant keepers ask eventually. One of life's greatest questions as a plant keeper seems to be where do indoor gnats come from? Let's crack the Da Vinci Code:
Fungus Gnat Natural Habitats
Fungus gnats are often found in areas with decaying leaves, compost piles, and other decomposing plant material. These environments provide ample food sources for their larvae. They are attracted to moist, organically rich soil where they can lay their eggs. This includes soil in gardens, greenhouses, and even the wild.
Fungus Gnat Sources Indoors
New Houseplants: The moist soil of indoor plants is an ideal breeding ground for fungus gnats. When purchasing plants, they frequently come with freebies for you to enjoy, like fungus gnats.
Contaminated Soil & Potting Mix: Potting soil that contains organic materials like peat moss or compost can come with free fungus gnats. We recommend sterilizing potting soil to avoid infestations.
Windows and Doors: Adult fungus gnats can enter homes through open windows and doors, especially if there are plants nearby.
Damp Areas: Areas in the home that remain damp, such as basements, bathrooms, and kitchens, can also attract fungus gnats. They are drawn to the moisture and potential organic debris present in these areas, laying eggs in the wet areas to hatch in 4-6 days.
What Are Fungus Gnats?
Fungus gnats are small, dark, delicate-looking insects that belong to the order Diptera, commonly known as true flies. Within this order, they are classified into two families: Mycetophilidae and Sciaridae. These families encompass a variety of species that share similar characteristics and behaviours.
Taxonomy and Classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera (True Flies)
Families: Mycetophilidae and Sciaridae. Fungus gnats are part of the larger group of insects known as flies, which are characterized by having a single pair of wings, where most others have two.
Physical Characteristics
Fungus gnats are tiny insects, typically measuring about 3-4 mm (1/8 inch) in length. They have slender bodies, long legs, and long antennae. Their wings are clear or dark, and they have a distinct Y-shaped vein pattern that can be seen under a microscope.
Ecological Role
Fungus gnats play a role in the decomposition of organic matter. Their larvae feed on fungi and decaying plant material, helping to break down and recycle nutrients back into the ecosystem. However, in domestic and agricultural settings, they can become pests, particularly in greenhouses and indoor plant environments.
Habitat and Behaviour
Fungus gnats are commonly found in environments rich in moisture and organic material. They are attracted to moist soil, especially in potted plant, decaying organic matter, such as leaves, compost, and other plant debris, and fungi, which serve as a primary food source for their larvae.
Significance
While fungus gnats are important decomposers in natural ecosystems, they can be problematic in controlled environments like homes and greenhouses. Their presence can indicate overwatering or poor soil conditions, which can lead to further issues for plant health.
Fungus Gnat Life Cycle
Fungus gnats, scientifically known as members of the families Mycetophilidae and Sciaridae, are small, dark, and delicate-looking flies that are often found around houseplants and other moist environments. Understanding their life cycle is crucial for effective control and prevention. Here’s a detailed look at the different stages of their life cycle:
Egg Stage
Location: Fungus gnats lay their eggs in the top layer of moist soil or organic matter.
Appearance: The eggs are tiny, white, and oval-shaped.
Duration: This lasts for 4–6 days.
Larval Stage
Location: The larvae live in the soil and feed on fungi, organic matter, and sometimes the roots of plants.
Appearance: They are legless, translucent white to clear, with black heads.
Duration: This lasts for 2–3 weeks.
Impact: Larvae can cause significant damage to plants by feeding on their roots, leading to poor plant health and growth.
Pupal Stage
Location: The pupae are found in the soil, where they undergo transformation into adult gnats.
Appearance: They are small, white, and encased in a protective cocoon.
Duration: This lasts for 3–6 days.
Adult Stage
Location: Adult fungus gnats are often seen flying around plants, especially in moist and shady areas.
Appearance: Adults are small, about 1/8 inch long, with long legs and antennae, and dark-coloured bodies and wings.
Duration: Adults live for 7–10 days.
Role: Adult fungus gnats do not cause direct harm to plants, but they lay eggs in the soil, continuing the cycle of infestation.
Fungus Gnat Lifespan
The total fungus gnat lifespan varies slightly depending on environmental conditions, but generally, the lifespan of a fungus gnat from egg to adult death is around 4–5 weeks. From the time the eggs are laid to death, the gnat life expectancy is approximately 25–35 days.
Key Points
Moisture Dependency: The life cycle of fungus gnats is highly dependent on moisture. Keeping the soil dry can break the cycle.
Reproductive Rate: Fungus gnats can reproduce rapidly under favourable conditions, making it important to take prompt action.
Damage: The most harmful stage is the larval stage, as larvae feed on plant roots, leading to stunted growth and sometimes plant death.
Do Fungus Gnats Lay Eggs In Your House?
Unfortunately, gnats lay eggs in your house. That's a fact that most people won't like to hear. Fungus gnats primarily lay their eggs in moist soil or organic debris, such as piles of leaves, compost, and mulch. However, they can also lay eggs in other moist areas within your home, which can make controlling a fungus gnat invasion very difficult when you can't find the source of the eggs. Fungus gnats are attracted to rotting or decaying organic matter, as they rely on fungi and bacteria that grow on such material for food. Here's how they detect it:
Scent: Rotting organic matter emits specific odours that fungus gnats are naturally attracted to2. These odours are produced by the fungi and bacteria breaking down the organic material.
Moisture: Fungus gnats are drawn to moist environments because their larvae need moisture to survive and grow. Rotting material often retains moisture, making it an ideal breeding ground.
Visual Cues: While not as significant as scent and moisture, fungus gnats can also be attracted to visual cues such as the presence of mould or mildew on decaying matter
By detecting these signals, fungus gnats can find suitable environments to lay their eggs and ensure their larvae have access to food sources. Whilst uncommon, fungus gnats can lay their eggs inside your home. Here are the places where fungus gnats nest in the house:
Drains and Pipes: Fungus gnats can lay eggs in the slime that accumulates in dirty drains, sinks pipes, and garbage disposals.
Cracks and Crevices: They may lay eggs in cracks and crevices where floors and walls intersect, especially if there is organic debris present. Use caulk or sealant to fill any cracks and crevices where floors and walls intersect, especially if there is organic debris present.
Mops and Brooms: If these cleaning tools are not cleaned properly and contain organic matter, they can become breeding sites.
Rotting Organic Mulch: Organic mulch like orchid bark, or coco coir husks used in plant pots can also be a breeding ground for fungus gnats.
While it's less common for fungus gnats to lay eggs in walls or floors, they can still find suitable conditions if there is moisture and organic matter present. Keeping your home clean, dry, and free of organic debris can help prevent infestations. If you suspect eggs have been laid in these areas, manually clean what you can by hand, and place sticky traps near potential breeding sites to catch adult gnats before they can lay eggs. Sprinkle diatomaceous earth around areas where you suspect eggs might be laid. The sharp particles will cut through the larvae and kill them. Use a hydrogen peroxide solution (1 part 3% hydrogen peroxide to 4 parts water) in a spray bottle applied in the problem areas of your home to kill larvae and eggs. Always test this solution for each surface before using it to prevent damage.
Fungus Gnat Prevention
Preventing fungus gnats involves creating an environment that is less attractive to them. Here are some effective strategies:
Manage Soil Moisture: Fungus gnats thrive in moist environments. Ensure your soil is well-drained and avoid overwatering. Allow the top layer of soil to dry out between watering to make it less hospitable for egg-laying.
Use Bottom Watering: Instead of watering from above, use bottom watering techniques. This method helps keep the surface of the soil drier, reducing the attraction for adult gnats.
Improve Soil Drainage: Add perlite, sand, or other well-draining materials to your potting mix to enhance drainage. This helps prevent the soil from staying too wet.
Sticky Traps: Place yellow sticky traps near your plants to catch adult fungus gnats. These traps are effective at reducing the adult population and breaking the life cycle.
Sanitize and Clean: Keep your growing area clean and free of decaying organic matter. Remove dead leaves and other debris that can contribute to a moist environment.
Use Neem Oil: Neem oil is a natural insecticide that can be mixed with water and applied to the soil. It helps to repel and kill fungus gnats.
Top Dressing: Apply a layer of sand or fine gravel on top of the soil. This creates a barrier that prevents adult gnats from laying eggs in the soil.
Monitor and Quarantine: When bringing new plants indoors, inspect them for signs of infestation. Quarantine new plants for a few weeks to prevent potential pest introductions to your other plants.
Every Natural Way To Get Rid Of Fungus Gnats That Actually Works
Managing garden pests doesn't always require harsh chemicals. Natural pesticides and home remedies can be just as effective while being safer for the environment, beneficial insects, and human health. Never re-use old chemical spray bottles, as it's impossible to remove all traces. Use a fine pressurised spray for maximum effects.
Top Dressing Plant Pots:
Effectiveness: Effective as a preventative measure. One of the most effective remedies. Widely reported online to be the final nail in the coffin for gnats.
How it works: Add a barrier layer of sand, gravel, coir husk, orchid bark, or pebbles on top of the soil. Sand is the most effective as it also heavily dries out the soil, preventing eggs from being laid and stopping larvae from reaching the surface due to the density of the grains of sand. Gravel is the next most effective treatment.
Soil Drying:
Effectiveness: Preventative measure.
How it works: Allow the top layer of soil to dry out between watering. Fungus gnats thrive in moist environments.
Bottom Watering:
Effectiveness: Effective as a preventative measure.
How it works: Water plants from the bottom to keep the top layer of soil dry, making it less attractive for gnats to lay eggs. Wet soil is the no.1 cause of fungus gnats.
Sticky Traps:
Effectiveness: Catches adult gnats.
How it works: These traps catch adult gnats on their sticky surface, preventing them from laying eggs.
Hydrogen Peroxide Solution:
Effectiveness: Kills larvae.
How it works: Mix one part 3% hydrogen peroxide with four parts water. Water the plants with this solution to kill larvae in the soil.
Diatomaceous Earth:
Effectiveness: Kills larvae.
How it works: Sprinkle a layer on the surface of the soil. The sharp particles cut the larvae, causing them to dehydrate and die.
BTI (Bacillus thuringiensis var. israelensis):
Effectiveness: Kills larvae.
How it works: This naturally occurring bacterium targets and kills fungus gnat larvae. Found in products like mosquito dunks or bits, it can be sprinkled on soil and mixed with water.
Neem Oil & Soap Spray:
Effectiveness: Effective against both adults and larvae.
How it works: Disrupts the life cycle of the pests. Mix 1 teaspoon of neem oil with 1 litre of water and 1–2 tablespoons of soap, and spray on affected plants.
Rubbing Alchohol Spray:
Effectiveness: Effective against adults.
How it works: Mix one cup of rubbing alcohol with one quart of water and spray the mixture directly onto the gnats to kill adults on contact. Test first and don't overuse as it damages houseplants.
Cinnamon:
Effectiveness: Moderately effective as a repellent and antifungal.
How it works: Sprinkle ground cinnamon on the surface of the soil. Its antifungal properties help control gnats by reducing the growth of fungi that gnats feed on.
Apple Cider Vinegar Traps:
Effectiveness: Effective as a trap for adult gnats.
How it works: Create a trap by filling a small container with apple cider vinegar and a few drops of dish soap. The gnats are attracted to the vinegar, get trapped by the soap, and drown.
Garlic and Onion Spray:
Effectiveness: Moderately effective as a repellent.
How it works: Blend 1 garlic head and 1 onion, mix with water, let it steep, strain, add 1–2 tablespoons of horticultural soap, and spray on plants.
Potato Slices:
Effectiveness: Moderately effective for trapping larvae.
How it works: Place raw potato slices on the soil surface. Fungus gnat larvae are attracted to the potatoes and can be removed along with the slices after a few days. Old home remedy, not the most effective.
Predatory Mites, Insects & Nematodes To Kill Fungus Gnats
Sometimes, natural is best. Although often expensive, beneficial insects can be a great way to prevent or control a pest infestation. When dealing with severe pests on your houseplants, use beneficial insects in combination with other treatment methods. Never use chemical or systemic pesticides at the same time as beneficial insects, as this could wipe them out. Let's explore which beneficial insects kill which pests:
Predatory Mites That Remove Fungus Gnats: These mites target fungus gnats:
Hypoaspis Miles: One of the few predatory mites for fungus gnats, offering effective biological control.
Nematodes That Kill Fungus Gnats: There are a couple of types of nematodes that remove fungus gnats:
Steinernema feltiae: Perfect nematodes for fungus gnats, also kills thrips, and other soil-dwelling pests.
Steinernema carpocapsae: Perfect nematodes for fungus gnats, typically mixed with feltiae.
Parasitic Insects That Kill Fungus Gnats: If you don't mind insects, this is another natural way to kill fungus gnats:
Predatory Beetles — Atheta coriaria: Predators of fungus gnats, but they can't survive below 25 °C (77 °F)
What Chemicals Kill Fungus Gnats?
When natural remedies and beneficial insects aren't enough to manage pest infestations, chemical pest treatments can provide a more immediate solution to finally get rid of fungus gnats in your home for once, and for all:
Cypermethrin
Cypermethrin is a synthetic pyrethroid insecticide that acts as a fast-acting neurotoxin, interfering with their nerve signalling. Py Bug Killer, and RoseClear Ultra Gun 2 are good choices.
Permethrin Smoke formulations
Permethrin smoke formulations contain permethrin, a synthetic pyrethroid for the instant death of flying and crawling insects. DeadFast Greenhouse Smoke Generator 2, and Vitax Greenhouse Fumigator are good brands.
Deltamethrin
Synthetic pyrethroid insecticide, which disrupts the nervous system of insects, leading to paralysis and death. Toxic to aquatic life, causes skin and respiratory irritation. Baby Bio Houseplant Bug Killer, Provanto Ultimate Bug Killer, Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer, and Toprose Bug Killer are good choices.
Lambda-cyhalothrin
Synthetic pyrethroid insecticide used to control a wide range of pests. It works by disrupting the nervous system, leading to paralysis and death. Highly toxic to fish, aquatic invertebrates, and bees. Use Resolva Bug Killer with caution.
For prolonged infestations, rotate between different types of insecticides to prevent pests from developing resistance. Chemical insecticides should be used carefully to avoid harming beneficial insects, plants, and the environment.
Safety Information For Fungus Gnat Treatments
Safety goggles or a face shield can help prevent chemicals from splashing into your eyes. Use chemical-resistant gloves to protect your hands from exposure. Wear a mask or respirator to avoid inhaling fumes or particles. Long-sleeved shirts, long pants, and shoes are essential to prevent skin contact.
Applying Pesticides Safely
Always read and follow the instructions on the pesticide label. This includes proper usage, dilution, and application techniques. Prepare pesticides in a well-ventilated area, preferably outdoors, to minimize inhalation risks. Ensure that sprayers and other application equipment are in good working condition to avoid leaks and spills. Apply pesticides directly to the affected areas, avoiding excessive use and reducing the risk to beneficial insects. Wash your hands, face, and any exposed skin thoroughly after handling pesticides. Remove and wash contaminated clothing separately. Store pesticides in the original bottles, sealed, away from children and pets. Label any leftovers. Never pour leftovers down the drain or into the soil.
The Last Fungus Gnat Treatment Guide You'll Need
If you've tried every chemical, every natural treatment, every home remedy, and you still have fungus gnats landing in your drinks, we've got you. We've combined safe treatments together with natural methods to make the ultimate fungus gnat removal guide, to end your war with gnats for once, and for all. Don't be afraid to jump in at the deep end. Although it may seem overwhelming at first, you'll soon realise how a multipronged approach to fungus gnat treatment will be the final nail in the coffin for your pest infestation.
Day 1: Initial Assessment, Preparation & Instant Actions
Identify Infested Plants: Check for signs of fungus gnats, such as small flies hovering around the soil and larvae in the top layer of the soil.
Remove Decaying Organic Matter: Remove any dead plant material, as this is a breeding ground for fungus gnats.
Soil Drying: Allow the soil to dry out completely between watering, making the environment less hospitable for gnats.
Bottom Watering: Water plants from the bottom to keep the top layer of soil dry, reducing gnat breeding grounds.
Sticky Traps: Place sticky traps around infested plants to catch and kill adult gnats. These traps use bright colours (usually yellow) to attract adult gnats, and the adhesive surface traps them, preventing further egg-laying.
Top Dressing for Pots: Add a layer of sand, gravel, or perlite on top of the soil in your pots. This creates a physical barrier that prevents adult gnats from laying eggs in the soil and makes it more difficult for larvae to reach the surface.
Neem Oil & Soap Spray: Mix 1 teaspoon of neem oil, 1 teaspoon of mild liquid soap, and 1 litre of water. Shake well and spray on soil and plant leaves. The mixture suffocates and deters gnats. Allow your plants a day to rest before continuing on to the next treatment.
Day 3: Hydrogen Peroxide Soil Soak For Fungus Gnats
Hydrogen Peroxide Solution: Mix 1 part hydrogen peroxide (3% solution) with 4 parts water. Water plants with this solution to kill larvae by oxidizing them. Wait 10 days before introducing biological controls after using peroxide. Allow your plants a day to rest before continuing.
Day 5: Apply Cypermethrin To Get Rid Of Fungus Gnats
Cypermethrin: Apply this insecticide to the soil to kill adult gnats by disrupting their nervous system. Wait 48 hours before applying Deltamethrin.
Day 7: Apply Deltamethrin To Get Rid Of Fungus Gnats
Deltamethrin: Apply this insecticide to the soil to kill larvae by disrupting their nervous system. Wait 48 hours before using Permetherin.
Day 9: Use Permethrin Smoke Bombs To Get Rid Of Fungus Gnats
Permethrin Smoke Formulations: Use these formulations to target and kill adult gnats in the air by affecting their nervous system. Apply this treatment 24 hours after using Cypermethrin and Deltamethrin. Allow your plants to rest for one day before continuing the next treatment.
Day 11: Apply Garlic & Onion Spray (Optional)
Garlic and Onion Spray: Mince 1 garlic bulb and 1 small onion, soak in 1 litre of water for 24 hours, strain, and spray on soil and plant leaves. Repels gnats with its strong odour. Note: After applying chemical treatments, wait at least 7–10 days before introducing biological controls to ensure the safety and effectiveness of beneficial organism. Allow your plants a day to rest before resuming treatment.
Day 13: Apply Apple Cider Vinegar Traps & Potato Slices
Apple Cider Vinegar Trap: Pour 1 cup of apple cider vinegar, 1 tablespoon of dish soap, and 1 cup of water into a small container. Cover with plastic wrap, poke holes, and place near infested plants. The trap attracts and drowns adult gnats.
Optional Potato Slices: Place thin potato slices on the soil surface to attract fungus gnat larvae. After 24-48 hours, check for larvae, discard the slices, and replace them until the infestation is reduced. This method works because the larvae are drawn to the moist potato, which acts as a bait. However, it may not eradicate the problem and is best used with other treatments. Allow your plants to rest for one day before resuming treatment.
Day 15: Apply Cinnamon (Optional) & Remove Potato Slices
Cinnamon: Sprinkle cinnamon on the soil; acts as a natural fungicide and deters gnats. Remove the potato slices, and rest one day.
Day 17: Apply Mosquito Bits (Optional)
Mosquito Bits: Sprinkle Mosquito Bits on the soil surface. These contain Bacillus thuringiensis israelensis (BTI), which kills gnat larvae by producing toxins that affect their gut. Note: BTI is banned in several countries, including Australia, New Zealand, Canada, the UK, the EU, and Japan, due to environmental impacts. Provide the plants with one rest day before moving on to the next treatment.
Day 19: Apply Diatomaceous Earth
Diatomaceous Earth: Sprinkle a thin layer of food-grade diatomaceous earth on the soil surface. It kills gnats by dehydrating and damaging their exoskeletons. Apply this after using potato slices to avoid interference. Provide the houseplants with a rest day before starting the next treatment.
Day 28: Second Hydrogen Peroxide Drench For Fungus Gnats
Hydrogen Peroxide Solution: Mix 1 part hydrogen peroxide (3% solution) with 4 parts water. Water plants with this solution to kill larvae by oxidizing them. Wait 10 days before introducing biological controls like nematodes, predatory mites or insects at the same time as using peroxide.
Day 38: Introduce Biological Control To Fight Fungus Gnat Re-Infestations
Hypoaspis Miles Predatory Mites: Introduce these mites to the soil; they feed on fungus gnat larvae, reducing their population. Optimal temperature is 15-25 °C (59-77 °F) with moist soil, and humidity should be kept between 60-80%. Re-application: Every 4–6 weeks if the infestation persists or as a preventive measure.
Steinernema Feltiae Nematodes: Apply these nematodes to the soil; they infect and kill gnat larvae by releasing bacteria. Optimal temperature is 14-26 °C (57-79 °F) with moist soil, and humidity should be kept above 40%. Re-application: Every 2–4 weeks until the gnat population is under control.
Steinernema Carpocapsae Nematodes: Use these nematodes for a broader approach to target larvae, killing them by parasitism. Ensure soil temperature is above 10 °C (50 °F) and below 35 °C (95 °F), with humidity above 40%. Re-application: Every 2–4 weeks if necessary.
Atheta Coriaria Predatory Beetles: Introduce these beetles to the soil; they prey on gnat larvae, reducing their numbers. Optimal temperature is 19-26 °C (67-79 °F) with relative humidity between 40-99%. Re-application: Every 4–6 weeks if the infestation persists or as a preventive measure.
Step 7: Maintenance and Prevention
Regular Monitoring: Keep an eye on your plants for any signs of re-infestation.
Proper Watering Practices: Avoid overwatering and ensure good drainage.
Soil Aeration: Regularly aerate the soil to prevent moisture build-up.
Timeline for Using Treatments
Day 1: Start with removing organic matter, soil drying, bottom watering, sticky traps, and top dressing for pots. Apply neem oil & soap spray.
Day 2: Rest day.
Day 3: Apply hydrogen peroxide solution.
Day 4: Rest day.
Day 5: Apply Cypermethrin. Allow 2 rest days to ensure that the chemical treatments don't interact.
Day 8: Apply Deltamethrin. Allow 2 rest days to ensure that the chemical treatments don't interact.
Day 9: Apply Permethrin Smoke, then allow one rest day.
Day 11: Apply garlic and onion spray (optional), then one rest day.
Day 13: Set up apple cider vinegar traps. Place optional potato slices on the soil surface, then rest for one day.
Day 15: Remove the potato. Apply (optional) cinnamon to the soil. Allow one day for it to kill fungal sources that feed fungus gnats.
Day 17: Sprinkle BTI mosquito bits (optional) on the soil surface. Allow one rest day.
Day 19: Apply diatomaceous earth. This will not negatively effect the BTI treatment and will aid it to work more efficiently. Allow 7 days rest.
Day 28: Reapply hydrogen peroxide solution to the soil if needed. Allow 10 days rest for the peroxide to disperse before continuing.
Day 38: Introduce predatory mites, nematodes, and beetles to the soil. Monitor temperature and humidity to ensure their survival.
Day 39 Onwards: Maintain bottom watering practices and regular monitoring. Reapply hydrogen peroxide solution every 2-3 weeks if necessary, and continue adding biological control as a preventative, allowing 10 days rest between hydrogen peroxide and adding predatory mites, insects, or nematodes. You should see a massive reduction in fungus gnats at this point in the treatment, if there are any left at all. If you are still seing fungus gnats in your house, it may be worth checking for other places where they could be breeding. If none of these have worked, you can try a systemic approach. We've listed all systemic pesticides that are suitable to be used to kill fungus gnats below. When reusing chemicals, check our reapplication guide below to check how frequently you can safely use pesticide to kill fungus gnats.
Why Rest Days are Important
Giving your plants rest days between treatments is essential to avoid overwhelming them and causing stress. Multiple treatments can be harsh, especially if used in quick succession. Rest days allow plants time to recover, ensuring they remain healthy and resilient. By spacing out treatments, you reduce the risk of damaging the plant's leaves and roots, leading to better overall effectiveness in eliminating fungus gnats.
The Ultimate Guide: How To Kill Fungus Gnats For Good
Say goodbye to fungus gnats in your mouth and hello to our ultimate guide on how to get rid of fungus gnats from your house. Although they don't do much damage to your plants, they certainly do significant damage to our patience levels! You've tried the rest, now test the best.
Systemic Pesticides To Treat Fungus Gnats
If you are still seeing pests after trying all natural and chemical fungus gnat removal methods, it may be time to try a systemic approach. Although they can be hard to find in some countries, there are a few options for systemic treatments if our other methods have failed:
Imidacloprid: This insecticide is absorbed into the plant's system, and when fungus gnat larvae feed on the roots, they ingest the insecticide and are killed. It remains effective for several weeks and can be used in combination with other treatments, such as sticky traps and biological controls, but ensure no direct conflict with soil-based treatments. It is approved for use in the United States, Australia, New Zealand, Canada, Brazil, and the UK, but is restricted in the EU due to harmful effects on bees. Although imidacloprid is legal in the UK & EU, it's usually sold for use on fleas.
Stubborn Infestations & Repeated Reapplications Of Pesticides & Insecticides
Fungus gnats can be challenging to eliminate due to their rapid life cycle and ability to breed in the moist environments of plant soil, or even in our homes. Their larvae feed on organic matter and fungus in the soil, which can be hard to completely eradicate. Moreover, the adult gnats can quickly re-infest areas if not all larvae and pupae are effectively controlled, making it crucial to consistently follow through with treatments, and to try a multi pronged approach to get rid of fungus gnats. If the infestation is still present after day 27, the following treatments can be repeated:
Biological Control Reapplication Guide
Biological controls like predatory mites, nematodes, and beetles are generally safe for repeated use. However, introducing them too frequently without allowing the initial populations to establish can reduce their effectiveness. It's essential to follow re-application intervals to ensure that the biological controls can establish and maintain a stable population. Here is how often you need to re-apply nematodes to kill fungus gnats:
Hypoaspis Miles Predatory Mites: Reapply every 4–6 weeks if the infestation persists or as a preventive measure.
Steinernema Feltiae Nematodes: Reapply every 2–4 weeks until the gnat population is under control.
Steinernema Carpocapsae Nematodes: Reapply every 2–4 weeks if necessary.
Atheta Coriaria Predatory Beetles: Reapply every 4–6 weeks if the infestation persists or as a preventive measure.
Chemical Control Reapplication Guide
Repeated use of chemical controls like Cypermethrin, Permethrin Smoke Formulations, and Deltamethrin can be harmful to plants over time. These chemicals are designed to be potent and effective against pests, but their frequent application can lead to phytotoxicity, where the chemicals damage plant tissues. Overuse can also disrupt the soil microbiome, harming beneficial organisms and potentially leading to chemical build-up in the soil, which can affect plant health. Here are the safe windows of treatment for these fungus gnat chemicals:
Cypermethrin: Reapply as needed, following the specific instructions for safe use and intervals between applications.
Permethrin Smoke Formulations: Reapply as required, following the specific instructions for safe use and intervals between applications.
Deltamethrin: Reapply as required, following the specific instructions for safe use and intervals between applications.
Natural Remedy Reapplication Guide
Some natural remedies, though generally safer for plants, can also cause issues with repeated use:
Hydrogen Peroxide Solution: While effective for killing larvae, frequent applications can disrupt the soil microbiome and damage plant roots. It's best to use this solution sparingly, every 2–3 weeks, ensuring it is not used if beneficial nematodes are present.
Neem Oil & Soap Spray: Though relatively safe, overuse can lead to a build-up of oil on the plant leaves, causing them to become more susceptible to sunburn and other environmental stresses. It's advisable to use neem oil & soap spray weekly or as needed, ensuring not to over-treat the plants.
Insecticidal Soap Spray: Similar to neem oil, frequent use can harm plant leaves. It's best to test it on one leaf first and avoid repeated applications if the plant shows signs of stress. Can be reapplied weekly or as required, ensuring that plants are not over-treated.
Garlic and Onion Spray: Can be reapplied weekly or as needed.
Apple Cider Vinegar Trap: Replace the traps as needed to continue attracting and trapping adult gnats.
Cinnamon: Reapply as needed to maintain its deterrent effect. You do not need to wait to reapply this.
Diatomaceous Earth: Reapply as needed to maintain a barrier on the soil surface. You do not need to wait to reapply this.
Mosquito Bits: Reapply every 2–4 weeks if necessary.
Sticky Traps: Check every 14 days and replace as needed.
Tips for Safe Reapplication
Always monitor your plants for signs of stress or damage and adjust treatment frequency accordingly.
Use chemical controls as a last resort and follow recommended intervals. This guide lists every treatment that can be used together in combination, designed for people who have tried everything else without success. Start by using natural methods first, then chemicals if that fails.
Rotate between different treatment methods to prevent potential resistance and minimize the risk of harming your plants.
There must be at least a 10-day gap between the application of hydrogen peroxide (Days 3 & 24) and the introduction of biological controls (Day 34). This ensures that the treatments do not interact and provides a safe interval to protect the effectiveness of the beneficial organisms. This timeline ensures a sufficient rest period between hydrogen peroxide applications and the introduction of biological controls, avoiding harmful interactions and ensuring the effectiveness of each treatment.
What To Do If You Can't Get Rid Of Fungus Gnats In Your Home
If you can't seem to get rid of fungus gnats in your home, the first step is to take a multi-faceted approach. Start by ensuring your plants' soil is well-drained and not overly moist, as gnats thrive in damp conditions. You can also repot your plants with fresh, sterile soil to eliminate any larvae or eggs that might be present. Using sticky traps can help catch adult gnats, reducing their population. Consider applying a biological control, like predatory nematodes or if it's available in your country, you can try beneficial bacteria (BTI), to target larvae in the soil. As a complete Hail Mary, we suggest trying permethrin smoke bombs. If the first application of smoke doesn't work for you, try again with more bombs. You may have not had enough chemicals released for the size of your treatment area. Don't forget to check other areas in your home where they may be breeding. If the measures in this fungus gnat removal guide don't work, including systemic pesticides, you might need to consult a professional pest control service for more targeted solutions. Remember, persistence and consistency in your efforts are key to managing and eventually eradicating fungus gnats.
Fungus Gnats Frequently Asked Questions
What Attracts Fungus Gnats?
Fungus gnats are attracted to moist soil and organic matter, where they lay their eggs. Overwatering plants and having rich organic soil can create an ideal environment for them.
Where Do Fungus Gnats Come From?
Fungus gnats typically come from outdoor sources, but they can also be brought indoors with infested potting soil or plants. They thrive in moist, organic-rich environments.
Do Fungus Gnats Bite?
No, fungus gnats do not bite humans. They are primarily a nuisance due to their presence and the potential damage their larvae can cause to plants.
What Do Fungus Gnats Look Like?
Adult fungus gnats are small, black, or dark grey insects with a wingspan of around 3 mm. They have long legs and antennae and resemble tiny mosquitoes. Larvae look like small, white worms in moist, organic soil.
How Long Do Fungus Gnats Live?
Adult fungus gnats live for about one week, but they can lay up to 300 eggs in their lifetime, which contributes to their rapid population growth.
What Are Fungus Gnats?
Fungus gnats are small flies that infest soil, feeding on decaying organic matter and fungi. Their larvae can damage plant roots, making them a concern for gardeners and indoor plant enthusiasts.
What Eats Fungus Gnats?
Predatory insects like nematodes, mites, and certain beetles, as well as biological control agents like Bacillus thuringiensis israelensis (BTI), can help manage fungus gnat populations.
Are Fungus Gnats Harmful?
While adult fungus gnats are mostly a nuisance, their larvae can harm plants by feeding on roots, leading to poor plant health and growth.
How to Kill Fungus Gnat Larvae?
Treat the soil with hydrogen peroxide solutions, neem oil, or biological control agents like BTI and beneficial nematodes to kill fungus gnat larvae.
Does Hydrogen Peroxide Kill Fungus Gnats?
Yes, hydrogen peroxide can kill fungus gnat larvae in the soil. Dilute hydrogen peroxide with water and apply it to the soil to help manage larvae.
How to Keep Gnats Away from Plants?
Keep the soil dry, use bottom watering, apply sticky traps, and consider using neem oil or cinnamon on the soil surface to repel gnats.
Can Fungus Gnats Kill Plants?
Fungus gnat larvae can cause significant damage to plant roots, potentially killing young or weak plants if left uncontrolled.
Does BT Kill Fungus Gnats?
Yes, Bacillus thuringiensis israelensis (BTI) is effective in killing fungus gnat larvae. It is a biological control agent that targets larvae in the soil.
Does Bleach Kill Fungus Gnats?
Bleach is not recommended for killing fungus gnats as it can harm plants and beneficial microorganisms in the soil. It's better to use targeted treatments like hydrogen peroxide or BTI.
What Causes Fungus Gnats?
Fungus gnats are often caused by overwatering plants and using soil rich in organic matter. Moist, decaying matter provides an ideal breeding ground for them.
What Do Fungus Gnat Eggs Look Like?
Fungus gnat eggs are tiny, white, and oval-shaped. They are usually found in moist soil near the surface.
Why Am I Getting So Many Gnats in My House?
Gnats can infest homes due to overwatered plants, damp environments, and poor soil drainage. They are attracted to moisture and organic matter.
How to Get Rid of Gnats Inside the House?
Identify and remove the source of moisture, set up apple cider vinegar traps, use sticky traps, and treat infested plants with appropriate pesticides or biological controls.
How to Stop Gnats from Flying Around You?
Gnats are attracted to moisture and carbon dioxide. Reduce moisture sources, use fans to create air movement, and consider using natural repellents like citronella or essential oils.
How to Keep Gnats Away from Your Face?
Wear light-coloured clothing, use natural repellents, and avoid using heavily scented products that may attract gnats. Fans can also help keep them away by disrupting their flight.
Can Fungus Gnats Harm Humans?
No, fungus gnats are not harmful to humans. They can be a nuisance, but they don't bite or pose any health risks.
What is the fastest way to get rid of fungus gnats in my house?
Using Bacillus thuringiensis var. israelensis (BTI) is considered one of the most effective methods. It's an organic larvicide that you sprinkle on the soil, and it targets the larvae.
Do Fungus Gnats Die In Winter?
Fungus gnats can slow down or become less active in colder temperatures, but they don't necessarily die off completely.
Does Dish Soap Kill Fungus Gnats?
While non-antibacterial natural dish soap can help in controlling adult gnats, it's not the most effective solution. Using yellow sticky traps and reducing watering can be more effective.
Will Fungus Gnats Go Away On Their Own?
Fungus gnats are unlikely to go away on their own without intervention. Reducing moisture and using treatments like BTI or sticky traps are necessary to eliminate them.
What Is The Life Cycle Of Fungus Gnats?
Fungus gnats undergo a four-stage life cycle: egg, larva, pupa, and adult. The entire cycle takes about 3–4 weeks under optimal conditions4.
How long do fungus gnats live?
Adult fungus gnats typically live for about a week, but they can lay up to 300 eggs during that time.
What is the best way to prevent fungus gnats?
Preventing fungus gnats involves managing soil moisture. Avoid overwatering, use well-draining soil, and consider bottom watering to keep the top layer of soil dry.
Are There Any Natural Remedies For Fungus Gnats?
Yes, natural remedies include using diatomaceous earth, neem oil, and cinnamon. However, their effectiveness can vary, and they may need to be reapplied regularly.
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