Re: Robber screen and SHB
I use robber screens - many with window screen. I think that they confuse the hive beetles a bit, but I'm not sure that it makes much of a difference - they still get in. It can't hurt though. Also a hive which is stressed by robbing is certainly more likely to be hurt by SHB. Robber screens also help with yellow jackets - which were particularly bad this past fall. I think that anything which improves overall hive health and lowers stress makes it less likely that SHB will cream them.
So, short version - Robber screens help prevent SHB problems, but not necissarily by keeping them out of hives. In my opinion.
5Y-25H-T-Z6b-0 winter losses in '14