No matter how lovely and sunny it is here in Florida the one thing you can count on that at some point or another you will encounter the dreaded FLORIDA GNAT!
We have had few problems with this thankfully but we do have to deal with flying stuff too. Last year we purchased these two items that have made ALL the difference. There is nothing more satisfying that listening to the sound of "ZAAAAAPPPPP"
https://www.amazon.com/gp/product/B001QBPP66 and this little Gem keeps all of the Skeeters that chase me out of my car. I literally applied one of these on the inside of my windshield! They would probably work phenomenally as Gnat control if you put them on the top of your Roach bin, just make sure you're roaches can reach up that far LOL