We plant lovers don’t want to witness plants being harmed by pests. The problem enters our homes, which is gross, therefore we especially don’t want to see pests in our houseplants! Fungus gnats are pesky, winged insects with little wings that resemble mosquitoes and are about the size of fruit flies. The good news is that compared to many other pests, these plant flies cause significantly less harm, and even better, they’re rather simple to get rid of.
Long legs, transparent wings, and a preference for nutrient-rich, damp soils are characteristics of fungus gnats. These little flies may be seen flying around plant containers, but unlike some more dangerous pests, you won’t observe them actually chewing on the plant’s foliage. However, you will see them in the soil, feeding on the organic matter and hairs from plant roots. Do not underestimate the damage that these bugs can still do if not addressed.
Even though adult fungus gnats only live for about a week, they can have a big impact in that short time by producing up to 300 eggs under the correct circumstances. With such a quick turnaround and a brief life cycle of about 3–4 weeks, populations can grow incredibly quickly.
It’s rather simple to tell if your plant has a fungus gnat issue. Since these plant flies can’t fly very well, they usually stay rather near to the plant. They’ll probably be moving in zigzag patterns while you watch them. It’s typical to witness all the different phases of this bug at once because they reproduce so quickly. It’s likely that some bugs still in their larval stage will be visible if you gently agitate the soil. They inhabit the earth where they eat organic debris and have translucent bodies and glossy, black heads.
Our plants are getting ready to settle in for the upcoming cold season as winter approaches here in North Dakota. Unfortunately, that signals that these pesky bug populations are about to reach their peak. During this time, dormant plants use less water, which causes their soil to stay moist for longer. Gnats thrive in moist soils because they promote root rot and fungus. Be cautious when bringing delicate plants inside to overwinter since you run the risk of inviting unwelcome pests into your house.
Your plants will start to exhibit signs of stress if ignored and neglected. Fungus gnats don’t directly harm plant leaves, but they eat the root hairs and deplete the soil of vital minerals. This may result in abrupt plant withering and yellowing of the leaves, sluggish development, and a general decline in vigor.
When tackling any pest, you should always start with natural management approaches. The least hazardous and disruptive to your plant and house are typically natural and organic remedies, while chemicals may occasionally be required as a second line of defense. Fortunately, most fungus gnat populations may be controlled and eliminated naturally provided they are discovered and dealt with in a timely manner. Remember that one plant container can hold three to four generations of bugs, so you’ll probably need to apply your favorite approach more than once. Gnats in your indoor plants can be managed in the following ways:
Do not overwater. Before watering your indoor plants, allow the top couple of inches of soil to dry up. This will not only stop fungus gnats from deciding that your plant would make the best place for them to live, but it will also interfere with their reproductive cycle and assist to reduce populations that have already moved in.
Activate sticky traps. Not just for mice, either! Sticky traps are easy fixes for many pest issues. Gnats that are moving will be caught if you place them immediately on the soil’s surface. To stop them from laying eggs, remove them from the trap, discard them, and replace it frequently (every two to three days). Particularly effective at drawing these insects, yellow traps are.
Create vinegar and cider traps.
Mix equal volumes of cider and vinegar in a shallow dish or can to act as a trap for fruit flies. Lay the trap on the soil surface inside the container or even next to the damaged plant. The concoction will attract the bugs, who will then fall into it and drown.
Bring in useful nematodes. Although it may seem counterproductive to introduce additional bugs into the equation, doing so is a simple way to reduce pest numbers. Nematodes are incredibly minute, worm-like insects that are frequently invisible to the unaided eye. In their larval stage, they attempt to infiltrate fungus gnats and other insects, releasing a bacteria that eventually consumes the pest from the inside out. When you think about it, it’s awful and disgusting, but not as disgusting as allowing gnats to devour your prized houseplants!
If all else fails, there are always insecticidal goods and sprays to keep pest numbers under control. There are many products available that either target the adult stage or the larval stage, but either is OK. You should be able to get rid of these unpleasant plant flies in a few of weeks as long as you successfully target one phase of their life cycle and reapply often.
Larvae are easily eliminated with hydrogen peroxide since it kills them immediately upon contact. Infuse your soil with a solution made of four parts water and one part hydrogen peroxide.
To destroy larvae, neem oil can also be put to the soil after being diluted with water. Neem oil can also be sprayed on surfaces to instantly kill adult flies. Last but not least, pyrethrin sprays contain extracts that are harmful to a variety of pests and can instantly kill flies and fungus gnat larvae.
Fungus gnats can affect the health of your houseplants even though they don’t transmit any diseases that are dangerous to humans. Your plants will thank you by giving off a lush, healthy appearance to enliven your home if you keep pests at away.
How can fungus gnats in houseplants be eliminated?
The small black bugs that you see swarming around your indoor plants are called fungus gnats. Fungus gnats are not enjoyable at all, and getting rid of them from indoor plants can be difficult. Fortunately, I can provide you some excellent advice to help you permanently get rid of these pesky little critters.
How to eliminate fungus gnats from indoor plants: There are six ways to get rid of fungus gnats in houseplants:
- Use a solution of water and hydrogen peroxide.
- Observe the drying of the potting soil.
- Plant repotting or replacement of the growth media
- Yellow sticky cards can be used to lure and capture fungus gnats.
- Pesticides should be added to the potting soil.
- Utilize a biological pesticide
Fungus gnats are generally innocuous as adults, but the larvae can injure property. The majority of the time, larvae consume algae and fungi, but they can also consume soil-dwelling plant roots, which can result in root injury and reduced growth. Fungus gnats should ideally be exterminated as soon as you see them. Continue reading to discover how to successfully eradicate fungus gnats from indoor plants and how to avoid repeat infestation.
Are houseplants harmed by fungus gnats?
Insects from the Sciaridae family called fungus gnats are frequently connected to overwatered houseplants. When they are present in great numbers and fly over a house, they can become an annoyance. Fungus gnats are typically just an aesthetic issue. But occasionally, fungus gnat larvae can harm plants.
The adult fungus gnat is a little, dark brown or black fly that is about 1/8 inch long. When they are at repose, their wings, which are black and translucent, fold on their backs. The vein patterns on the wings of adult fungus gnats allow them to be differentiated from other tiny flies. Fungus gnat wings have a distinctive spherical Y-shaped collection of veins near the wing tips that may be seen under a microscope. The larvae of fungus gnats (maggots) look like whitish worms and have a black head. When mature, they measure 1/4 inch in length. Although these two insects are different, fungus gnats and fruit flies are sometimes confused (see University of Wisconsin Garden Facts XHT1102, Fruit Flies in the Home).
Symptoms and Effects: Fungus gnats are typically found inside when adults fly near light sources (such as windows or lamps), or when they fly close to or cross over potted plants’ soil and rest there. Adult fungus gnats are an aesthetic annoyance but do not feed on or harm plants. Larvae of fungus gnats typically eat fungi in the soil and decomposing organic debris. However, if there are a lot of larvae, they could eat the root hairs or burrow into the roots, damaging them. In a household environment, this kind of damage is uncommon.
Life cycle: Each year, fungus gnats can produce many generations. Fungus gnats frequently have overlapping generations indoors, with eggs, larva, pupae, and adults all present at once. In the damp soil of potted plants, fungus gnat females can lay up to 200 eggs (in clusters) in cracks and fissures. Usually, the eggs hatch in three to six days. Before pupating close to the soil’s surface, larvae go through four phases (referred to as instars) over the course of one to two weeks. Adult fungus gnats emerge four to five days after pupae form. Adults only live for about one week on average. Fungus gnats can grow from an egg to an adult in three to four weeks under ideal circumstances.
Scouting Advice: Use yellow sticky traps set close to a plant’s leaves to keep an eye out for adult fungus gnats. These traps are available at your neighborhood hardware or garden store. Sticky traps are simple to use with potted plants because they are affordable and frequently come with little stakes. Sticky traps can help you maintain track of the amount of fungus gnats (and other insects) over time in addition to helping you catch adult fungus gnats and other insect problems. Monitoring for fungus gnats cannot be done using vinegar traps or other techniques that are frequently used to check for fruit flies.
Place potato slices on the soil surface of potted plants to check for fungus gnat larvae. Fungus gnat larvae will surface to feed on the tissue of the potato plant if they are present in the soil. After three to four days, check the slices for maggots.
Non-Chemical Control: As mentioned before, utilizing sticky traps can aid in the management of fungus gnats. However, the single most crucial action in managing this insect is changing the environmental conditions of houseplants. Keep the soil surface dry to remove the insect’s preferred egg-laying areas. To achieve this, wait one inch below the surface of the soil before watering. As an alternative, you can water from the bottom to keep the soil surface dry while giving the roots hydration. Additionally, you can add a 1/2 to 1 inch layer of coarse sand or fine gravel to the soil to assist keep the top dry and reduce the soil’s appeal to hens looking to lay eggs.
When houseplants that have spent the summer outside and grown contaminated are brought inside for the fall, fungus gnats are frequently a bigger issue. To control fungus gnats, it can require three to four weeks of adjusted watering and the usage of sand/gravel.
Biological control: Homeowners can use products like Gnatrol, Mosquito Bits, etc. that contain Bacillus thuringiensis subsp. israelensis (Bti) to suppress fungus gnat larvae in soil. Adult fungus gnats, pupae, or eggs are not harmed by these treatments. Applying these substances with enough water will aid Bti in passing through the soil and reaching the larvae. Until the infestation is under control, make additional applications spaced five to seven days apart to control newly hatched larvae.
Chemical measures are not necessary until the fungus gnat infestation is severe. However, pesticides using pyrethrins or synthetic pyrethroids can offer momentary control if adult populations are high. If you choose to use insecticides, choose one that is approved for use inside on houseplants and make sure to read and abide by all instructions on the label. Use pesticides on plants and the soil’s surface where adults usually repose. Spraying the air with these products is not recommended because they are useless. Remember that using chemicals shouldn’t be your only management strategy, even in cases where using insecticides may be necessary. Always use insecticides in conjunction with other non-chemical methods (see above).
Can fungus gnats cause plants to regenerate?
So your African violets have been invaded by fungus gnats? Let’s now discuss methods for managing both adult flies and fly larvae. Here, we advise using an integrated pest management strategy to cover all your bases and permanently safeguard the inhabitants of your greenhouse and houseplants.
Organic Fungus Gnat Control
Surprisingly, one of my top suggestions for getting rid of these pests is a common household item. You can saturate soil in hydrogen peroxide (the standard topical variety, 3 percent).
Pour a solution of one part hydrogen peroxide to four parts water through the soil in the root zone of the pot until it starts to emerge from the bottom. On contact, fungus gnat larvae are killed by the peroxide.
Neem oil works well as a soil soak to get rid of fungus gnat larvae. Follow the manufacturer’s instructions to dilute the oil with water, then immerse the plant’s roots in the solution. To deter adult gnats, you can additionally spray the plant’s uppermost part.
Neem oil contains concentrated azadirachtin in its natural state. It is safe to use indoors, in greenhouses, gardens, and hydroponically. Use it as directed by the manufacturer, much like you would neem oil.
Sprays containing pyrethrin are also effective at killing fungus gnat larvae. Use pyrethrins by misting the soil’s surface and all plant surfaces with a light mist. A light mist will do; you don’t want the plants to get drenched. Spray the soil exactly where adults usually rest to completely hydrate the top if there are fungus gnat larvae present, then prevent overwatering. Let the soil dry to a depth of at least two. When the issue has passed and the insects are no longer a concern, reapply these after three to four weeks.
Adults and larvae are the targets of a predatory Hypoaspis miles mite. Additionally, it preys on other insects like thrips and springtails, which can be a pest in a greenhouse or garden. Since solitary specimens are more difficult to treat, these are best used outside or in greenhouses.
As you can see, there are numerous biological control treatments available for the removal of fungus gnats. Apply pesticides along with wise cultural habits and effective preventative measures, and you’re good to go!
Cultural Control of Fungus Gnats
Avoid flooding your growing media. These insects thrive in the moist growing medium found in houseplants. Do not leave standing water in saucers next to growing medium or below houseplants for an extended period of time. Keep your growth medium away from your potted greenhouse residents and fix any irrigation system leaks that develop. To get rid of any larvae that may be feasting on the organic elements in your compost, pasteurize the growing medium. If you don’t like the notion of doing it yourself, use heated commercial growing medium mixtures. While you take care of the issue, keep any sick plant material and growth medium away from other people.
Biological Removal of Fungus Gnats
Fungus gnat larvae can be killed by a specific strain of bacteria called Bacillus thuringiensis var. israelensis. Most commercial BT sprays do not contain these bacteria, although they are also present as active components in some commercial products. You should see a reduction in your fungus gnat issues if you use them to fertilize your growth media.
By scattering Mosquito Bits or Mosquito Dunks over the soil’s surface and soaking them in, you can also introduce this bacterium. These are suitable for usage both inside and outside. They aren’t just used to kill mosquitoes! As they decompose, Bacillus thuringiensis var. israelensis is released into your soil, where it can begin to kill larvae. Mosquito dunks are more substantial and take longer to work.
The eradication of the fungus gnat larvae might also be greatly aided by the species of beneficial nematodes. The fungus gnat larvae and many other soil-dwelling pests will be eliminated by these microscopic soil dwellers, which you cannot see. Use a pot popper to incorporate these nematodes into the soil when treating an indoor plant. Commercial formulations can cover a larger garden or the entire yard since they uniformly distribute the nematodes with water.
Be warned that using a hydrogen peroxide soil drench and helpful nematodes at the same time will kill the nematodes! Nematodes should not be added back into the soil for at least a few weeks following the infestation. Nematodes should be used in cooler weather if you’re working outside because heat will kill them before they can perform their job. Keep in mind that you must apply more than once, twice a year.