Midges that hover around your houseplants are called sciarids, or “soil flies”.
These are these tiny black dipterans that fly away, in swarms, as soon as you approach a potted plant.
Why do houseplants attract gnats?
Not only is it unpleasant to have midges in our homes, but, in addition, the females have the annoying habit of laying their eggs in
substrates rich
in organic matter and moist,
such as potting soil for indoor plants.
This is where the danger for plants comes from.
Within a few days, the eggs turn into voracious larvae that feed on root hairs, preventing the plant from feeding.
Its development is then impaired and, in the event of a large infestation, it can wither away.
Another risk: wounds caused by larvae and midges can allow pathogenic bacteria and fungi to enter.
Knowing that a female midge can lay between 50 and 300 eggs, we quickly understand the benefit of getting rid of them as quickly as possible.
Also read Topsoil: what is it?
Female midges lay their eggs in substrates rich in organic matter and moist, such as potting soil for houseplants.
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No use without permission.
7 tips to prevent midges from coming
Avoid keeping the potting soil moist
, if the plant can handle it.
By letting it dry out on the surface between two waterings, midges will not come and lay eggs in it.
Also remember to empty the water from the saucer, ½ hour after watering;
Hide the surface of the potting soil under a thin layer of small pebbles or coarse sand.
Midges will be hampered in laying their eggs, and eggs already in place will die.
On the other hand, do not use too fine sand which tends to mix with the potting soil, or even coffee grounds, as is sometimes recommended: it is organic matter which, on the contrary, attracts these pests;
Trap midges
to prevent them from breeding.
This will limit the infestation, but will have no impact on the larvae already in place: place yellow, sticky traps.
They are unattractive, but effective in capturing adult midges;
A homemade recipe:
pour a syrup made with honey and a little water into a bowl and place it near the potted plants.
Midges are like flies, they are attracted to sugar: they will drown in it.
Adopt a sundew:
it is a carnivorous plant whose sticky tentacles which cover the leaves are real traps for midges.
Scare midges away:
certain smells, like lemon or cloves, seem to keep them away.
As a reminder: the popular expression is “you can’t catch flies with vinegar”.
There is therefore no point in trying to capture midges with vinegar, whether white or cider.
Please note: some poor quality commercial potting soils may contain larvae.
Also read: Treatment against mealybugs: use white vinegar!
Yellow, sticky traps are unattractive, but effective in capturing adult midges.
Copyright (c) 2019 Amelia Martin/Shutterstock.
No use without permission.
How to get rid of midge larvae in potting soil?
When the larvae are in place, several options are available to you to exterminate them:
Repot the plant to change the substrate:
this is the first thing to do, when the size of the pot and that of the plant allow it;
Use predatory auxiliaries:
nematodes or mites sold in garden centers.
If you do not use auxiliaries, water the soil with water containing cinnamon and rose geranium essential oil, at a rate of 3 drops of each per 1 liter of water;
And if the infestation is not too heavy,
the layer of sand
should be enough to destroy the larvae in place before they do too much damage.