Nobody likes pests! Among the many kinds of pests, diseases, and fungal infections houseplants may contract, gnats are one of the harder ones to spot. They eat at the roots of your succulents and live in the soil, so finding them within succulent leaves like mealybugs or spider mites is rather unlikely. If you see these tiny insects around your home, check your soil first and foremost: it may just save your succulent’s life.
Types of Gnats You May Encounter
There are many different kinds of gnats, but only a few affect indoor plants and succulents. To look for gnats in your soil, examine it closely with a flashlight (with a magnifying glass if possible) to look for movement in the soil. Gnats may also rest on your succulent’s leaves from time to time. If you see gnats around your home, especially in rooms where you keep your succulents, the first place to check should be the soil. With a toothpick, cotton swab, or popsicle stick, gently stir around your succulent’s soil. If you see small insects or larvae in the soil as you stir it, you’ve got gnats.
1. Fungal Gnats
Fungal gnats are the most common kind of gnat you’ll encounter as a pest. These gnats are between 1/16 to 1/8 inch long, black or greyish, and have translucent wings. Fungal gnats tend to lay smooth ovular eggs that are translucent white. When checking the soil for signs of activity, keep an eye out for the small, white eggs or cocoons in the soil.
2. Buffalo Gnats
Buffalo gnats grow to about ⅛ of an inch long, and males like to feed on nectar from flowering plants. The females, however, enjoy snacking on blood. Buffalo gnats are typically tan, green, or grey, with tiny rounded wings like fungal gnats.
3. Gall Gnats
Gall gnats look a lot like mosquitoes, but unlike mosquitoes, they don’t bite. Instead, they feed off of plant sap as they grow and can hamper your plant’s growth in the process. Gall gnats are most often red, and their larvae appear flattened with tapered ends. Gall gnats are also hairy and have completely clear wings with one cross vein on each wing.
Where do they Come From?
All gnats reproduce in warm, wet conditions and lay eggs in droves. Although most gnats don’t live for more than a week, their rapid reproduction rate keeps them around for a while, so it’s best not to just “wait it out” and expect them to leave. Gnats make their homes in many places as well, and stopping the source of the problem might require some extra searching.
1. Fungal Gnats
Fungal gnats, as the name suggests, eat fungus that grows from warm, humid conditions. You’ll most likely find them if your succulent is overwatered or has root rot, but fungal gnats will also make their home in soil regardless of your succulent’s health. You might also find fungal gnats in sink drains, garbage cans, compost bins, or anywhere that is relatively dry but still plenty humid.
2. Buffalo Gnats
Buffalo gnats are often seen outside, but it’s not unheard of for the occasional buffalo gnat to wander in when your windows are open. Unlike fungal gnats, buffalo gnats prefer to lay their eggs in fast-moving rivers and streams and tend to avoid high-heat areas.
3. Gall Gnats
Gall gnats reproduce by injecting larvae directly into plant sap. While they are harmless to humans, gall gnats are capable of spreading infections to your succulents. Like buffalo gnats, gall gnats typically reproduce outdoors, but the occasional breach into your home isn’t unheard of.
Treating Your Succulents for Gnats
Since gall gnats and buffalo gnats are mainly outdoor insects, the best way to keep them out of your home is by controlling your indoor environment with air conditioning, heating, and keeping your windows closed. In the winter months, a humidifier may help prevent your succulents from drying out, while a dehumidifier in the summer can keep things from getting too humid.
For fungal gnats, there are several ways you can handle an infestation:
1. Using Traps
Fungal gnats eat almost anything, and one of the best ways to kill adults is by placing traps around your home. Flypaper and chemical gnat traps are one way to draw adult gnats away from your plants, but they may not be the most beautiful part of your living room. LED rechargeable insect traps use a combination of colored lights and fans to draw flying insects in and keep them there and are an effective long-term solution if you don’t have air conditioning.
Another way to trap fungal gnats is by making your own gnat trap using stuff you have around the house. To make a homemade gnat trap, pour apple cider vinegar or vinegar and a pinch of sugar into a small bowl, then mix with three or four drops of dish soap. Replace the bowl every two or three days, and you’re set! The dish soap will create a film that gnats can fall into but cannot fly out of, thus trapping them in the vinegar mixture.
2. Anti-Larval Killer
You can kill gnats and their larvae with chemicals as well, although it’s best to dilute anything you want to spray onto your succulents or their soil. Many gardeners recommend using diatomaceous earth-- an abrasive substance that kills pests by dehydration-- but your soil must be completely dry to do so. Instead, consider killing larvae with neem oil or hydrogen peroxide spray, with a few drops of oil/peroxide per tablespoon of water.
Preventing Future Infestations
The best way to prevent future gnat infestations is by changing your succulent’s environment. To do so, there are three main steps to follow:
1. Repot Your Succulent
First, repot your succulent. If you’ve got gnats in the soil, it can be hard to kill them all without replacing the soil in the first place, so consider cleaning out your succulent’s home and repotting it with a fresh soil mixture. As a reminder, it’s best to repot during the growing season, but repotting anytime in an emergency is okay.
2. Move Your Succulent
If your succulent is someplace prone to high humidity or fungal growth (say, a bathroom or near the kitchen garbage), move it to another location. Fungal gnats tend to enjoy places near the fungus they eat, so keeping your plants away from potential food sources removes one potential home for an infestation in the future.
3. Keep Your Soil Dry
Since fungal gnats live off fungus grown in warm, moist environments, succulents suffering from root rot or overwatering make for the perfect target. Fortunately, this problem is relatively easy to avoid with a few changes to your watering routine. For example, bottom watering your succulents will keep upper layers of soil from being soaked. Still, another method to gain complete control over your soil’s moisture is by monitoring the moisture levels daily. To do so, stick your finger an inch or two into the pot to feel if the soil is damp, or use a moisture meter to calculate moisture levels 24/7.
Like all pests, gnats are something you can chase away with a little extra love and effort. Your succulents will thank you for it!
See more about Signs of Healthy and Unhealthy Succulent Roots
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