This is a katchy, it helped me knock out the annoying adults while I could deal with the longer term infestation issue. My husband was super annoyed they were attracted to his computer screen so I set it up by him during the day and it seemed to help divert them.
To check if you have any drain issues put tape over the drain and see if you catch any overnight. I used this stuff and it sees to work well. FRUIT FLY GOODBYE Gel Drain Treatment | Drain Fly Killer | Fruit Fly Killer | Drain Flies Treatment | Fruit Flies Treatment | Drain Fly & Fruit Fly Eliminator (32 oz) https://www.amazon.com/dp/B07CVMMDNQ/ref=cm_sw_r_apan_glt_fabc_6A5VPGFR2BFKN2SK3QCW?_encoding=UTF8&psc=1
I used this stuff which is just citronella, water, and thickening agents; it adheres to the pipe walls and traps/kills them. I would also invest in the traps that are shaped like little apples, although I think the attractant/poison is just apple cider vinegar. My roommates are not good about dishes so I deal with this every few months and this combo clears them up in a day or two. Hope this helps!
My son tried for months to get rid of them in his college apartment. I bought him this and they were gone forever. I was literally a hero. Lol. Green Gobbler Fruit Fly Goodbye Gel Drain Treatment | Drain Fly Repellent | Fruit Fly Repellent | Drain Flies Treatment | Fruit Flies Treatment | Drai https://www.amazon.com/dp/B07CVMMDNQ/ref=cm_sw_r_cp_apip_NB5PjucK9MGut
Also try drain fly killer, this turned out to be our issue when traps quit working!
https://smile.amazon.com/dp/B07CVMMDNQ/ref=cm_sw_r_cp_apa_glt_fabc_TWE75Q9PACPWPF5FBKXM
https://www.amazon.com/Green-Gobbler-Goodbye-Treatment-Eliminator/dp/B07CVMMDNQ
That stuff down the drain every night, followed by boiling water in the morning. Works fine. Trapping is pointless.
Never heard of this tactic, but I bought some stuff off Amazon to pour down my drain: FRUIT FLY GOODBYE Gel Drain Treatment https://www.amazon.com/dp/B07CVMMDNQ/ref=cm_sw_r_apan_glt_fabc_BZMPJ5D7K58R7DH6566D
I'd also suspect drain flies. They get caught in the same traps as fruit flies and we thought we had fruit flies too, but one dose of this and we went from catching a ton every day to NOT A ONE. Pour it down every drain (kitchen, bathroom, etc.) and let it sit overnight before running more water down. The bottle says to reapply but we never had to. If you can't find them anywhere else, I bet this is where they're hiding. https://www.amazon.com/gp/product/B07CVMMDNQ