I visited the Bee Lab at the University of Georgia and one of the BEE PHD students was using a mouth aspirator on one of the hives. In about 30 minutes he sucked up every beetle we could find which was quite a few. I was extremely impressed. No chemicals, instant results, etc. He did not miss a single beetle and the mouth aspirator is totally controllable.
See what a mouth aspirator looks like or order one for yourself. gemplers.com/product/301053/Mouth-Operated-Aspirator. Go to the Gemplers web site and search on aspirator.