How to keep fruit flies out of plants

As people who adore plants, we never want to see them suffer at the hand of pests. But we especially don’t want to see pests in our houseplants, because that brings the problem inside our homes—gross! Fungus gnats are nasty little winged critters that resemble tiny mosquitoes and are similar in size to fruit flies. The good news is that these plant flies are much less damaging than many other pests, and better yet, they’re pretty easy to get rid of. 

What are Fungus Gnats?

Fungus gnats are identifiable by their long legs, transparent wings, and affinity for nutrient-rich, moist soils. You might notice these tiny flies buzzing around plant containers, but you won’t see them munching on the plant’s foliage directly, like some more harmful pests do. You will, however, notice them in the soil, feasting on plant root hairs and other organic matter. Make no mistake—if left untreated, these bugs can still cause a considerable amount of damage. 

While adult fungus gnats only have a life span of about a week, they can make a pretty significant impact in that short period, laying up to 300 eggs in the right conditions. With this fast turnaround and short life cycle lasting just 3-4 weeks, populations can skyrocket pretty quickly. 

Signs of Fungus Gnats

If your plant has a fungus gnat problem, it’s pretty easy to identify. These plant flies aren’t actually great at flying, so they tend to stay pretty close to the plant. You’ll probably notice them whizzing about in zig-zag movements. Since they have such a quick reproduction rate, it’s common to see all the different stages of this pest at once. If you gently stir around the soil, you’ll likely see some bugs still in their larval stage. They have transparent bodies and black, shiny heads, and live in the soil where they munch away on organic matter.

With winter upon us here in North Dakota, our plants are getting ready to settle in for the cold season. Unfortunately, that means it’s about time for these bothersome bug populations to peak. Dormant plants need less water during this time, meaning their soils stay wet longer. Wet soils, which encourage root rot and fungus, are a breeding ground for gnats. Be careful bringing your tender plants inside to overwinter, as you might be introducing your home to unwanted pests.

If left unnoticed and untreated, your plants will begin to show signs of stress. While fungus gnats don’t damage plant leaves directly, they munch on root hairs and diminish the soil of essential nutrients. This can lead to the sudden wilting and yellowing of plant leaves, weak growth, and an overall loss of vigor.

Natural Ways to Get Rid of Gnats

Natural control methods should always be your first step when dealing with any pest. While chemicals are sometimes a necessary second line of defense, natural and organic solutions are usually the least harmful and disruptive to your plant and home. Luckily, most populations of fungus gnats can be prevented and eradicated naturally if they’re identified and treated in time. Keep in mind that one plant container can house 3-4 generations of bugs, so multiple applications of your preferred method will likely be necessary. Here’s how you can control gnats in your houseplants:

Avoid overwatering. Allow the top few inches of soil to dry out before watering your houseplants. Not only will this prevent fungus gnats from choosing your plant as their ideal new home, but it will also disrupt their reproductive cycle and help to lessen populations that have already moved in. 

Use sticky traps. They’re not just for mice! Sticky traps are simple solutions to a lot of pest problems. Place them directly on the surface of the soil, and you’ll catch gnats that are on the move. Remove them from the trap or dispose of and replace the trap often (every 2-3 days) to intercept their egg-laying. Yellow traps are especially efficient at attracting these insects.

Make cider and vinegar traps. Similar to how you might trap fruit flies, mix equal parts of cider and vinegar in a shallow dish or can. Place the trap near the affected plant or even on the soil surface inside the container. The pests will be attracted to the mixture but will drown after they land in it.

Introduce beneficial nematodes. Adding more bugs to the mix might sound counterproductive, but it’s a straightforward solution to controlling pest populations. Nematodes are teeny tiny worm-like bugs, often so small that you can’t even see them with your naked eye. They work to penetrate fungus gnats and other insects in their larval stage, releasing a bacteria that ends up consuming the pest from the inside out. It’s grim and gross when you think about it, but not as gross as letting gnats kill your precious houseplants!

Dealing with Fungus Gnats in Houseplants

When all else fails, there are always insecticidal products and sprays available to control pest populations. There are plenty of products that target either the larval stage or the adult stage, but either is fine. As long as you effectively target one stage of their life cycle and reapply frequently, you should be able to eradicate these nasty plant flies in just a few weeks.

Hydrogen peroxide is a quick and effective way to get rid of larvae, killing them on contact. Mix four parts water with one part hydrogen peroxide and soak your soil with the solution. 

Neem oil can also be diluted with water and applied to the soil to kill larvae. You can also use neem oil as a spray to kill adult flies on contact. Finally, pyrethrin sprays contain extracts that are toxic to many pests and can kill fungus gnat larvae and flies on contact.

Although fungus gnats don’t carry diseases that pose a threat to human health, they can impact the health of your houseplants. By keeping pests at bay, your plants will return the favor with a luscious, healthy appearance to brighten your home. 

An annoying issue most gardeners speak of is fruit flies in indoor plants. They do not have much interest in houseplants other than decaying organic matter.

If you have kept any over-ripe or rotten fruits near your indoor plants, fruit flies are bound to wander around there. But they won’t necessarily harm your plants.

With that said, let us find out how to get rid of fruit flies in indoor plants.

Here are 7 effective ways to get rid of fruit flies in indoor plants:

1. Move the soil around to remove any decaying material on topsoil.
2. Remove any food source like fruits and veggies present near the plants.
3. Clean the pots and surfaces around the plant.
4. Set some fly traps around your plant pots.
5. Grow bug-repellent indoor plants.
6. Use neem oil or other insecticides to get rid of them.
7. Don’t keep windows and doors open unnecessarily as that allows them entry to your home.

Fruit flies are found in indoor plants because your potting soil has decaying organic matter or fungus. They will even lay eggs on the surface of the potting soil.

To get rid of fruit flies from your indoor plants you can follow the steps mentioned above, and read this article till the end to learn the steps in detail and to understand the reasons behind their appearance.

Some links in the post are affiliate links and I get a commission from purchases made through links in the post.

What are fruit flies, and where do they come from on your indoor plants?

Before addressing the issue, let us understand what fruit flies are and how they reach your indoor plants.

Fruit flies are common household pests. They are primarily seen during the late summers and fall months. They have red eyes, brown bodies, and are very small in size. If growing conditions are ideal, fruit flies will live up to 40 to 50 days.

They are found chiefly near overripened or rotten fruits, fermented vegetables, and moist areas.

They like to feed on the decaying organic matter in the potting soil. Moreover, if the potting soil remains moist most of the time, it becomes another advantage for fruit flies.

If you have kept any ripened and rotten fruits near your indoor plants, that can also be why fruit flies surround your plant.

Some of us confuse fruit flies with fungus gnats. Fungus gnats, too, are the flies that like loitering near the indoor plants. Gnats look like mosquitoes, black in color, but fruit flies have brown bodies. 

Also read: How To Get Rid Of Gnats In Indoor Plants? (Identification, Causes & Solution)

Why do you need to remove fruit flies?

Fruit flies do not cause any harm to your houseplants. They only come to the indoor plant soil to feed on the decaying matter.

When they approach your plants and find conditions ideal for their stay, they will lay eggs on the surface of the soil.

Fruit flies can lay up to at least 500 eggs at a time. Although fruit flies do not harm the plants, they are health hazards. That is why it is better to remove them.

Looking for a readymade indoor plant soil mix that you can open and pour? Check out rePotme. They offer a wide range of readymade soil premixes for all your indoor plants.

How to get rid of fruit flies?

Fruit flies are not much attracted to indoor plants.

They enter our home because they get attracted more to fermented fruits and vegetables or overripe and rotten fruits, dustbins, etc.

Before you take steps to remove fruit flies from the plant, remove the items attracting the fruit flies.

Taking the garbage bins outside and keeping fruits covered or in refrigerators will help eliminate fruit flies from the house.

Also, clean the refrigerators where fruits are kept. Fruit flies don’t have a problem staying in cold areas. Clean the areas where you prepare food to keep them away. Fruit flies won’t come near clean places.

If your kitchen has bins to discard scraps or compost heaps, make sure they are sealed well. This can also be an attraction for fruit flies.

Now, coming to indoor plants, if your house’s surroundings are kept clean, the fruit flies won’t be able to infest your plant much, the decaying organic matter in the potting soil is exceptional.

Still, if they are infesting your plant, your plant or potting soil has something which attracts them. Now, let us how to get rid of fruit flies from the indoor plants:

Disturb the soil

Fruit flies will infest your potting soil for two reasons. First is, they will feed on the decaying organic materials present in the soil.

Secondly, if the indoor plant soil and plant crevices have fungus, the presence of fruit flies should not be surprising.

Fruit flies will also lay eggs below the soil’s surface if the condition is ideal for them.

The larvae will start growing on the micro-organisms which live in the dark and moist soil. If your potting soil is healthy, the fruit fly larvae will get all their needs from your potting soil.

Disturbing the soil will disturb the breeding process of the fruit flies. For this, turn over the surface soil and expose the eggs or the larvae towards the light and dry air surrounding your plant.

You can create an obstacle between the soil and the air by placing a thick layer of course gravel.

Another way of disturbing the eggs or larvae of the fruit flies is to allow the topsoil to dry out completely. But for this, you need to know whether your plants will be able to tolerate drought.

If the flies still don’t go away from the soil, you might have to opt for re-potting the plant. Collect and place the larvae in a sealed container and discard them far away.

Dispose of the infested soil much away from your home. Wash and disinfect the pot for further usage.

Remove the food source

Most potting soil has decaying organic components, a good food source of fruit flies, for example, peat moss.

But peat moss is very beneficial for indoor plants, and it might not be possible to remove it. You can also use perlite in your potting soil. It is lightweight compared to peat moss.

Another good food source for fruit flies is a fungus. The quicker you remove fungus from the plant, the fewer fruit flies will wander near your indoor plant.

Prevent fungus and fruit flies by decreasing the humidity around your indoor plant. The fruit flies breed mainly in damp and moist areas. But, before reducing humidity, make sure that your plant can tolerate the situation.

You can use dish wash soap for spraying or rubbing alcohol to wipe out all sorts of fungus and pests from your plant. This will prevent any further appearance of fruit flies.

Clean all surfaces

Always try to keep the sink drains free from all sorts of food particles and residue. These damp spots are the best place for the fruit flies to stay and lay eggs.

If you keep wet clothes or rags in rooms where you have placed your indoor plants, move away either the wet clothes and rags or the plants away. Keep your plants away from such damp environments to avoid fruit fly infestation.

Throw away the over-ripe or rotting fruits away

For keeping the indoor plants free from fruit flies, you will need to keep your house clean.

If you are growing fruit plants indoors, you should pinch off the ripening fruits from them as soon as possible. Keeping ripen or rotten fruits away from the plant will help keep fruit flies at bay to some extent.

Set traps

DIY FLY Trap to Get Rid of Flies and Fruit Fly

Fruit flies can be lured by vinegar, wine, or yeast as they are attracted to them.

Mix apple cider vinegar and dish wash liquid soap with water and pour it into a bowl. Cover the container with a wrapper.

Make holes over it big enough for the fruit flies to get into it. Now place the container near the infested plant. They will enter into that bowl through these holes but won’t be able to come out.

Take an old wine or beer bottle and place it near the infested indoor plant. They will be attracted by that old, stale smell and enter the bottle. The narrow-necked bottle will make it difficult for them to come out of it.

You can also buy flytraps from the market. These will not only trap them but also stop them from further breeding.

These are disposable fly traps entrapped with a non-toxic lure. This will be able to catch at least 2,000 fruit flies. The product will last at least one month. 

Growing indoor plants that can repel insects

Plants like mint, basil, sage, lemongrass, lavender, marigolds, and many more are popular houseplants that repel insects.

The flies cannot stand the presence of some insecticidal components in them and their strong odor. Thus, the fruit flies will stay away from the indoor plants.

Another plant that can keep flies away is carnivorous plants, such as venus flytraps or pitchers. These kinds of plants will eat up the fruit flies once they land in their mouth. They, too, are one kind of trap for them.

Use insecticide

Now, if all the above methods are not working and whatever you do, fruit flies are still wandering near your plant or the potting soil, it is time to try commercial ones.

But as commercial insecticides contain chemicals, you should be careful while using them.

Read all the instructions given in the labels very carefully before applying. Go through the ingredients, the directions for use, and the caution and warning points. Also, consult with the buyer or experts about the best way to use them.

Don’t allow them inside.

You can close the windows and doors in the room where the indoor plants are kept. This might not be possible as plants will need air and sunlight to thrive. 

You can organize nets or any screen as a barrier to prevent the fruit flies from entering the room.

Also read: How To Get Rid Of Bugs On Indoor Plants? (Identification+Remedy)

Final words

Fruits flies are a common and annoying problem in houseplants. Even though they don’t harm the plants, they are a health hazard.

Moreover, their infestation can increase in no time that will give your plant a dull look. So, it is better to remove them as soon as possible.

Try all the methods alternately to remove them. First, try the natural ways and if it fails, go for the chemical treatments, but be careful. Always keep the surroundings of your indoor plants neat and clean.

Fruit flies don’t like neat places. Clean places will keep them away from your plants and even from your home. Take good care of your plants to keep the fruit flies away.

Source: University of Illinois, Growing Indoor Plants with Success, Agriculture, and Natural Resources, University of California, Missouri Botanical Garden.