Discover the soil fly
This little diptera, i.e. an insect with a single pair of wings, measures about 4 mm and, despite its small size, it can quickly become disturbing both for you and for your potted plants from which you can see it fly away before coming back to rest on the ground. If around your indoor plants or yourself you see fluttering a swarm of little gnats with a black and thin body, equipped with long thin legs, long antennae and dark wings, there is no doubt, the sciarids have invited themselves to your home and have found the sufficiently moist and rich soil in organic matter to want to stay there.
And who says sciarids says larvae. These small, 5mm translucent worms are white with a black head and are far more dangerous to plants than the flies themselves, as they feed on the root hairs of plant roots.
The life cycle of the fungus gnat
At first, adult flies may enter your home in the summer when the windows are open, or you may have purchased potting soil or a plant that is already contaminated. Either way, the result is the same. Here is the life cycle of these flies, from egg to adult:
- Immediately after emerging from the pupa, a female, who has only 7 days to live, can lay between 50 and 300 eggs. To deposit her eggs, she will look for a place rich in organic matter and humid. If it entered your home inadvertently, it may be in one of your flower pots, in the garden centre, it may opt for a flower pot or a bag of potting soil whose packaging is not completely airtight. You understand how you can inherit these flies after a purchase in a garden center. If she opts for a flowerpot, she lays her eggs as close as possible to the roots of the plant it contains.
- 5 days laterthese tiny white eggs hatch and larvae come out.
- For about two weeksthese larvae feed, among other things, on the root hairs of the roots.
- These larvae then pupate for about 5 days.. From these pupae then emerges a new generation of sciarids ready to mate and lay eggs.
So you understand that if you don’t act, the cycles will never end!
Damage that can be caused by the fungus gnat
Other than disturbing you when they fly or land on you, adult fungus gnats don’t really inflict any damage on plants. But the same cannot be said of the larvae which, by developing near the roots and feeding on them, can cause greater damage:
- Its roots being attacked, the plant can no longer feed properlyits leaves wither and it perishes.
- The lesions caused to the plant by flies and their larvae are so many open doors of entry for fungi and bacteria responsible for various diseases.
- Finally, it is not appreciated to see midges fly away as soon as the plant is affected.
It is rather plants with a moist substrate that will attract sciarids and much less succulent plants, cacti, etc.
Prevent the presence of the fungus gnat
For fight against the presence of the soil flyhere are some simple steps to take:
- Before using potting soil purchased from a garden center, sterilize it by putting it in the microwave for a few minutes.
- Avoid overwatering your plants. As these flies prefer moist soil to deposit their eggs, let the soil of the plants dry out between two waterings.
- Once your plants are watered, Remember to empty the water present in the cups. This stagnant water is not only bad for the roots of your plants, but it will also tend to attract fungus gnats.
- You can also cover the surface of the earth with small pebbles or sand. This environment will thus be less favorable and the fungus gnats will be less tempted to come and lay their eggs there.
- Opt for pots with a hole in the bottom and allows the flow of water.
- As much as possible, avoid gathering your plants all in the same place to limit the spread.
Fight against the presence of the soil fly
The traps
A first solution to fight against the presence of the fungus fungus is toto use traps. You can find sticky yellow traps on the market on which the insects stick. Just place them close to your plant. However, we are obliged to recognize that side decoration, it is not what we do best! Instead, you can put saucers in which you have diluted honey in water. They will have the effect of attracting flies which will drown in them. In the same way, you can also attract them with wine or vinegar.
diatomaceous earth
The diatomaceous earth is a very abrasive fine powder. Just sprinkle your potting soil with diatomaceous earth and mix. The larvae in contact with the silicon contained in this product will eventually die, because it acts as a natural insecticide.
neem oil
Another natural solution to quickly obtain results is neem oil. Commonly used in India, it is extracted from the almond of the neem tree and has an active ingredient, azadirachtin, which will harm the insect without presenting any danger to humans.
Here’s how to use it:
- Let the root ball dry out until the plant shows signs of dehydration.
- Mix 1 liter of water with 20 ml of neem oil.
- Water your plant with this mixture.
- Let it dry again before renewing the operation.
black soap
You can spray a mixture of black soap diluted in water on your plants. This mixture is harmless to plants and bothers soil gnats. This solution is very effective.
Lemon and cloves
Flies hate the acidity of lemon. You can thus create your natural repellent by pushing cloves into half a lemon for better effectiveness. All you have to do is put it on the soil to keep them away.
cinnamon
Cinnamon is also very effective in repelling flies from the soil. To do this :
- Boil cinnamon in water.
- Once the mixture has cooled, spray it on your plants to water them.
Essential oils
In a sprayer, dilute 3 drops of cinnamon essential oil and 3 others of rose geranium in 1 liter of water. Water your plants with this mixture.
Repot the plant
If your plant is the victim of too much infestation and you can’t get rid of it, the best solution is to change the soil. To do this :
- Remove the plant from its pot and remove all the soil.
- Thoroughly rinse the roots of your plant.
- Replant it in new potting soil.
This solution should only be considered as a last resort.