I made 5 traps, using the method outlined in my previous blog post about fruit flies.
These traps consisted of:
Trap #1 - My "control" trap, using fruit & yeast (which I've used for years)
Trap #2 - Apple cider vinegar & yeast
Trap #3 - Apple cider vinegar only
Trap #4 - Apples only
Trap #5 - Apples, apple cider vinegar & yeast
After 48 hours, still only one trap contained any fruit flies, which now numbered somewhere between 20 and 30 (they wouldn't stay still so that I could count them!)
I figured that the experiment could be stopped at that point, since there was a clear winner: you probably guessed it, it was Trap #1 (my old standby), containing apples and yeast. The other traps didn't even have one fruit fly in them, nothing, nada, nil.
So there you have it! My original recipe still stands.