You will need
- - dichlorvos;
- - sulphur;
- - new potting mix;
- - matches;
- - potassium permanganate.
As mentioned above, gnats appear in the damp earth. So stop watering, at least during processing plants. And further watering flowers rare. Generally in winter this must be done not more often 1 time a week. Sprinkle the soil in the pots with a layer of kiln wood ash. Lice cannot lay new eggs, they will just wallow in that ash. And their larvae will die, too. In addition, ash is an excellent potash fertilizer.
Stick in the ground near the flower heads a few matches down. Sulfur has a detrimental effect on the larvae of midges and they will disappear. And flying insects destroy dichlorvos or a similar drug. Just be sure to ventilate the room. You can still irrigate the land with a pink solution of potassium permanganate.
If flies still infest again, try to repot the flower in a new earth. The pot it is sure wash to eggs and larvae of these pests. Immediately sprinkle new soil with a layer of ash, it will not give a flying gnats, which have survived all previous measures, to lay eggs.
The most effective method, allowing to destroy the lice quickly and permanently is to apply insecticides. In specialized stores there are a lot of drugs, ask the seller advice, what to buy better. Just be sure to follow the instructions.
Help sticky baits near the flowers, some of the gnats will stick.