Small white flies in the house: what to do?

You have discovered small whiteflies in the house and wonder what these pests are and how you can get rid of them? Then you've come to the right place. In this article you will learn everything you need to know about the small whiteflies: what species there are, how you can recognize and distinguish them, which plants they infest and how you can fight them biologically and naturally.

What are the small white flies in the house?

Small whiteflies in the house are usually not true flies, but a kind of moth. They are about two to three millimeters in size and have white wings with which they quickly rise into the air when disturbed. They lay their eggs on the underside of leaves of crops and ornamental plants, where the larvae also reside. The larvae feed on the plant sap and weaken the plants. They also excrete a sticky honeydew that can attract smut fungi.

The most common type of small whitefly in the house is the glasshouse whitefly (Trialeurodes vaporariorum). It mainly attacks plants with soft leaves, such as tomatoes, peppers, cucumbers, zucchini or squash. But also ornamental plants such as geraniums, hibiscus, fleißiges Lieschen or primroses can be affected.

Small glasshouse white fly Trialeurodes vaporariorum
The glasshouse whitefly. Source: gaucho, Wikimedia Commons, CC BY-SA 3.0

Another type of small whitefly in the house is the dark-winged fungus gnat (Sciaridae). It is also called a black fly or soil pest because it has dark wings and lays its eggs in the soil. The larvae feed on the roots of plants and can cause them to die. Fungus gnats mainly attack plants with moist soil, such as ferns or orchids.

As you can see, the fungus gnat is of course anything but white, but since it is so small and shiny, it can certainly look that way in the light.

A fungus gnat (Sciaridae)
A fungus gnat. Source: xpda, CC BY-SA 4.0

How to recognize and distinguish small whiteflies?

If you want to know exactly which of the two species it is, you can tell by the appearance, egg laying, position of the larvae, and the pattern of damage that occurs.

Appearance

The whitefly has a yellowish body and white wings that lie roof-like over the body. The fungus gnat has a black body and dark wings that lie flat over the body.

Egg laying

The whitefly lays its eggs on the underside of leaves of plants. The eggs are white-yellowish to black. The fungus gnat lays its eggs in the soil, where they are usually barely visible.

Whitefly eggs
The eggs of the glasshouse whitefly. Source: Goldlocki, Wikimedia Commons, CC BY-SA 3.0

Unfortunately, I could not find a freely usable picture with the eggs of the fungus gnat. If you have a photo or know where there is one, please send me an email to jan@terrarium.blog!

Larvae

The larvae of the whitefly are whitish-yellowish and sit on the underside of leaves of plants. They have a pointed head and a round abdomen. The larvae of the fungus gnat, on the other hand, are whitish-transparent and crawl around in the soil, have a black head and an elongated body.

The larva of the glasshouse whitefly under a light microscope
The larva of the glasshouse whitefly. Source: Anatoly Mikhaltsov, CC BY-SA 4.0
The larva of a fungus gnat
The larva of a fungus gnat. Source: James Lindsey, CC BY-SA 3.0

Damage pattern

Whitefly causes yellow spots on the leaves of plants. The leaves may wilt or fall off. In addition, the plant may wither or die if the roots are too damaged.

How to get rid of small white flies in the house?

If you have small whiteflies in your house, you don't have to resort to chemical pest control. There are many organic and natural methods to control or prevent the pests. Here are some tips you can try:

Preventive measures

To avoid an infestation of small whiteflies in your home, you should keep the following points in mind:

  • Choose a suitable location for your plants. Most plants like it bright, but not too hot or too dry. Avoid drafts and direct sunlight.
  • Make sure your plants are in good health. Water your plants regularly, but not too much or too little. Use good quality soil and fertilize your plants as needed.
  • Place beneficial insects. There are some plants that attract natural predators of small whiteflies or act as deterrents to the pests. These include, for example, marigolds, nasturtiums, lavender or basil.

Combating measures

If you already have small whiteflies in your house, you can use the following methods to control them:

  • Use home remedies. There are some home remedies that are effective against small whiteflies. For example, you can make a spray solution of canola oil, soft soap and water and spray it on the infested leaves. The oil suffocates the pests and the soap cauterizes their skin.
  • Use yellow traps. Yellow boards are small sticky traps that you can buy at hardware stores or online. The small white flies are attracted to the paint and stick to the board. You can also make them yourself. All you need is yellow paper or cardboard, glue or honey, and a wire or wooden stick to hang them on.
  • Use nematodes. Nematodes are tiny nematodes that work against the larvae of small whiteflies. They penetrate the larvae and kill them. You can buy nematodes in stores or order them online. All you have to do is dissolve them in water and water your plants with them.

With these tips you can fight small whiteflies in the house biologically and naturally. If you have any questions or need further help, feel free to contact me at jan@terrarium.blog. I hope your house is fly-free soon!

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