Of course the sticky traps being sold on Amazon show these photos of the traps inundated with hundreds of fruit flies. They want us to buy their product. One plastic trap looks like a small pineapple. It opens, you put a trap inside, put on the cover, then squeeze liquid from a plastic tube through a hole in the top. I may have to go back and look again if these things don't bite the dust soon. I'm getting tired of swatting at them when they fly in front of my screen on my laptop.
Yes, I’ve seen people complain about the apple-shaped ones being pretty useless, too. I think they use something that smells like vinegar. But, again, the Raid ones are working well for us. You just need to find the bait that your breed of bugs likes. For us it was dark beer :-)