500-1000 beetles? That an insane amount of beetles. Sorry, Cao!!! Again, this July and August, I battle the beetles and will continue to do so until the ground cools. This year, I placed lime dust on the dirt in front of each hive. The lime has helped tremendously. I did lose a newly created nuc, one of three, a few weeks ago to beetles.
Lastly, I have placed one strong bait hive, directly under an oak, next to the forest, 100 percent shaded all day. This hive acts as my beetle trap as once a week, I go into this hive and kill all the beetles with hive tool and freeze spray. The beetles zero in on this all shaded hive on the wood line.
For those battling beetles, I hear you loud and clear. Which is worse: Varroa or small hive beetle? Yes