We had a very bad fruit fly problem and placed the traps out. Day one the flies just hang out by the trap. Day two some went inside the trap. A week later most gone. Two weeks later 3-4 flies still hanging around. I was hoping the flies would be drawn to the trap and be done with them in a few days. Not the case.
Expert response: The fruit fly traps will only catch adult fruit flies that are flying around. The traps alone will not get rid of fruit flies unless you find the source. If fruit flies are breeding from a piece of food that fell behind the stove and you do not get rid or find the food, you will continue to see the fruit flies in your kitchen or wherever they are. The traps only take care of the adults; you have to still eliminate the breeding site.
It works but a lot of the flies go in and come out...so it catches some, but not all. I finally had to spray all rooms and then purchase a UV light trap with sticky paper behind it...and that worked amazingly!