I’ve been having a fly problem this summer. Both lots of the regular big flies but that was earlier (they’re almost gone now) and these past few weeks fruit flies. I searched online and found all sorts of fly traps you can make; glass with various sweets (a fruit gone bad, balsamic vinegar, coke, “saft” etc) inside which entice flies, glass with paper funnel, glass with cling film with holes etc. Nothing really worked.
Until I realized that whenever I had a glass of rosé wine out those little buggers came and sat down on the rim or took a swim in my drink. So I took a glass, poured some rosé wine in it, added a couple of drops of dish washing soap (make them unable to land on the surface) and left it on the counter top.
At first nothing much happened but after a day or so I saw some casualties and after that they started piling up in there! There’s even a mosquito and a wasp so the wine turned vinegar must be really tasty now. A votre santé, creeps!