I've been spreading diatamatheous earth under the stands. also someone mentioned on another thread that they used butter flavored crisco for beetle bait. i had spme butter flavored cooking spray that someone gave me & i never used it ( & never will ). whwn i put the inserts into my screened bottom boards to test for mites there were a lot of dead beetles on the boards. i never use that type of stuff to cook & after seeing this i'm definitely never going to cook with it.
Dead beetles seems to say that the bees are learning how to catch and bite these boogers. I see the same thing in my OB hive. a lot of dead beetles in the bottom tray. If the bees can get them off a wall they curl up and try to bite them.
There is no oil in this tray to kill them.
I do find live ones but that just means that the bees kicked them out of the hive.