Pests
Fighting fungus gnats: How to get rid of the flying pests
Sciarid gnats can be effectively combated with so-called yellow traps
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Sciarid gnats are small black flies that nestle in the soil of indoor plants. Read here how you can effectively combat the pests and get rid of them in the long term.
At the latest when you discover small black flies, those affected will notice that fungus gnats have found their way into the home unnoticed. The flying pests hide in the potting soil of indoor plants and multiply quickly. The entire life cycle of the fungus gnat is only about three to four weeks, but the rapid reproduction of the animals keeps those affected on their toes in the long term. This is how an infestation must always be treated, because the plant pests do not go away on their own. Here you can find out how you can fight sciarid gnats and get rid of them in the long term.
What are fungus gnats?
In nature, the fungus gnat – especially the larvae – is one of the most important foliage-decomposing organisms and thus one of the useful animals. The flying pests are only considered pests if they attack indoor plants. Sciarid gnats are particularly common in the winter months, when the small animals often sit by the dozen on the potting soil of the plants. This is because people tend to overwater their houseplants in winter due to the dry heating air. Sciarid gnats love to lay their eggs in moist soil, where the larvae develop, feed on the soil and the roots and damage the plants. That is why potting soil that is kept too wet is the ideal habitat for the black flies. Sciarid gnats are one to seven millimeters tall and have a black body with long legs and black wings. The larvae are gray-white and six to seven millimeters long.
How do you recognize a sciarid gnat infestation?
Most people recognize an infestation with the fungus gnat when small black flies are buzzing through the air. The small pests are often mistaken for fruit flies, so it takes some time before the sciarid gnat infestation is identified. However, once you get to know the sciarid gnats, you will be able to easily distinguish them from fruit flies in the future. The mosquitoes fly up when you water the plants or when you move the plants. Sciarid gnat larvae are found in large groups on the moist plant roots, a glance into the soil of the affected plant is enough and you can see the larvae with the naked eye. As soon as one plant is affected, you should also check the other plants for an infestation, because the fungus gnats multiply quickly. It is best to isolate the infested plants from the rest until the infestation has been controlled.
Tip: If the potting soil is already too badly affected, you should repot the plant and implement the following tips for permanent control of fungus gnats.
How can you fight fungus gnats?
Moisture is the most important requirement for fungus gnats or for the survival of the larvae, so the first thing you should do is not water the affected plants for a while. Of course you have to watch the plants to prevent them from drying out, but for a short time this drying out can help against the sciarid gnats. In addition, the following measures can be effective in controlling fungus gnats:
Yellow trap
Sciarid gnats are said to be effective with so-called Yellow traps let fight. You stick the yellow sticker directly into the affected potting soil and the small insects stick to it.
Fighting fungus gnats with carnivorous plants
You can even use plants to fight the pests. Butterwort, a carnivorous plant that can trap the sciarid gnats with sticky leaves, is suitable for this. If you place the butterwort near the affected plant, the flies should stick to it.
Nematodes or predatory mites
In professionally managed garden operations, nematode and predatory mite species are also used to control or prevent sciarid fly larvae. Nematodes are, for example, beneficial insects for the sustainable and effective control of fungus gnats and their larvae. You can use a spray bottle or watering can to add them to the potting soil as a spray or pouring agent.
Home remedies for fungus gnats
A good home remedy for combating fungus gnats and their larvae is potting soil with a layer about one to two centimeters thick Quartz sand to cover. This prevents the adult flies from laying their eggs in the damp earth.
Do sciarid gnats harm people?
Sciarid gnats are harmless to humans, but they are very annoying. The flying pests are actually only harmful to indoor plants. In some cases, however, the increased moisture in the potting soil can cause mold to form on the earth, which should be removed quickly, as its vapors are not good for the human respiratory tract.
Preventing fungus gnats
Sciarid gnats often find their way into numerous households during the winter months. This is because houseplants are often not properly cared for. Therefore, a small digression into plant care makes sense in order to prevent pests such as the fungus gnats in the long term. In winter, plants get less daylight indoors and are usually in heated rooms, making them more susceptible to pests. The following tips can help keep the plants healthy.
- Sufficient light: Indoor plants often suffer from a lack of light in winter. In the winter months, therefore, place your plants near the window to counteract this situation.
- Remove dust: It is normal for dust to settle on the leaves over time, but this makes it difficult for the plant to absorb light. Therefore, it is best to remove dust with a damp cloth with warm, lime-free water (for example with boiled water).
- Pour correctly: Usually it is sufficient to water plants once a week. There are even plants that need water less often. Take the time to research the individual water requirements of your plant, this will prevent overwatering and, in the long term, a sciarid gnat infestation.
Source: Federal Environment Agency
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