Fighting scary mosquitoes and fruit flies
Many confuse mourning gnats and fruit flies.
Against fruit flies helps the already mentioned vinegar trick.
Against mourning flies, these little black things that live in and around the potting soil reliably only help nematodes. These are small parasites that attack only the sciarid fly larvae and otherwise are completely harmless to humans, animals and plants. These nematodes are available in specialist shops (garden department) in liquid solution for irrigation water. Incidentally, they also help against mosquitoes - simply into the rain barrel or other breeding grounds.
By the way, yellowsticks, flower changes etc. are not reliable methods to fight. Yellow stickers do not catch everyone and as soon as a fly is on the way (as well at Erdwechsel) go on.
