I use fruit flies in experiments all the time. They are notorious breeders (very prolific). The best trap I ever used was to place a funnel on a jar or glass (in my case a beaker) and add APPLE CIDER VINEGAR. Make sure there is at least 3/4 inch between the tip of the funnel and the top of the vinegar. Those little suckers fly in and can't get out. We use something similar when we are etherizing them except for the ether, of course.
This is one of those cases where you catch more flies with vinegar than honey. They are not really attracted to sticky strips, bug bombs are not a good idea and usually ineffectual on these little guys,