Controlling Fungus Gnats Around the Home

For those of us who hold plants in high regard, seeing them destroyed by pests is an unthinkable tragedy. Seeing pests in houseplants is especially revolting because it means we have to bring the problem indoors. Fungus gnats are small, winged insects that look like mosquitoes but are actually more closely related to fruit flies. The good news is that plant flies are not nearly as destructive as some other pests, and they can be easily eliminated.  

Fungus Gnats: What Are They?

The fungus gnat is easily recognized by its long legs, clear wings, and preference for damp, nutrient-rich soils. These tiny flies may be seen buzzing around plant containers, but unlike some more harmful pests, they do not directly feed on the plant's foliage. However, you will find them in the soil, where they feed on the root hairs of plants and other decomposing matter. Don't be fooled: if you ignore these pests, they can still cause a lot of damage.  

Fungus gnat adults only live for about a week, but they can produce a lot of offspring in that time (up to 300 in ideal conditions). This rapid reproduction and short life cycle of only 3–4 weeks can cause population explosions.  

Fungus gnats: the telltale signs

Fungus gnats are an easy indicator that your plant has a problem. Due to their poor flying abilities, plant flies typically remain in close proximity to their host plant. You'll see them zipping around in all sorts of unpredictable patterns. Due to the rapid rate at which this pest can reproduce, all of its life stages are often present at once. Some insects may still be in the larval stage if you gently stir the soil. They live in the soil, where they feed on organic matter, and have see-through bodies and shiny black heads.

Our plants are preparing for the North Dakota winter now that fall has passed. That's bad news because it means the worst of the annoying bug season is yet to come. As a result of their reduced water requirements, the soils of dormant plants retain more moisture during this time. Gnats thrive in wet soils because they promote root rot and fungal growth. Avoid inviting pests into your home by not bringing in your tender plants for the winter.

Your plants will show signs of stress if the problem is not addressed. While fungus gnats may not cause visible damage to plant leaves, their feeding on root hairs can deplete the soil of vital nutrients. As a result, plants may experience rapid leaf yellowing and wilting, stunted development, and a general decline in vitality.

Eliminating Gnats Naturally

The first line of defense against any pest should be natural methods of control. While chemicals can be useful as a last resort, organic and natural remedies typically cause the least damage to your plant and house. Fortunately, if fungus gnat populations are detected and treated promptly, they can usually be prevented and eradicated naturally. Remember that a single plant container can harbor three or four generations of insects, so it will likely be necessary to apply your chosen method more than once. Read on for some tips on keeping gnats away from your houseplants:

Stay away from soaking the lawn. The top few inches of soil should be allowed to dry out before watering indoor plants. This will not only prevent fungus gnats from settling on your plant, but it will also interfere with their reproductive cycle, reducing the number of gnats already there.  

Take advantage of sticky traps You can use them for more than just catching mice. Sticky traps are an easy way to solve numerous pest control issues. You can catch active gnats by placing them on the soil's surface. To prevent the eggs from hatching in the trap, they must be removed frequently (every two to three days). Traps that are yellow are the most effective at luring these pests.

Construct vinegar and cider receptacles To catch fruit flies, set up a trap like you would with a shallow dish or can filled with a mixture of equal parts cider and vinegar. Set the trap close to the diseased plant or directly on the soil in the container. Insects will be drawn to the mixture, but they will perish once they land in it.

Put in some helpful nematodes It may seem backwards to add more bugs to the mix in order to reduce pest populations, but this is actually a fairly simple strategy. Nematodes are microscopic, worm-like insects that are typically invisible to the naked eye. They infiltrate the bodies of fungus gnats and other insect larvae, releasing a bacteria that ultimately kills the pest. It's depressing and unpleasant to contemplate, but not as unpleasant as watching gnats devour your prized houseplants.

Home remedies for fungus gnats

When all else fails, insecticides and sprays can be used to reduce pest numbers. Both the larval and adult stages are fine, and many products exist for both. You can get rid of those pesky plant flies in a matter of weeks if you apply the right treatment at the right time in their life cycle and keep applying it.

Larvae can be killed instantly by contact with hydrogen peroxide. Soak your soil in a mixture of four parts water to one part hydrogen peroxide.  

Neem oil can be applied to the soil, diluted with water, to eliminate larvae. Spraying neem oil on adult flies is another effective way to get rid of them quickly. Sprays containing pyrethrin have toxic extracts that can kill fungus gnat larvae and flies instantly.

Fungus gnats aren't dangerous to humans, but they can harm your houseplants. In exchange for your efforts to protect your plants from pests, they will reward you with a more lush and healthy appearance that will enhance your home.