LLOYDSPEAR wrote:

>
>
>   If used with a closed bottom the
> > average
> > decrease in fall mite counts is 37% on average but with important
> > variations.  It seems also that the genetic origin of the queen and the
> > location of the apiary both have more impact on the mite levels than the
> > screened bottom.

Hello Lloyd and All,

 Thanks for the post. I have all of my hives on screens ( 150) with closed
bottoms.
I'm using Russian stock that has passed my Hygienic behavior check.Last year I
saw mites come and go
without treatment. It is more complex than just Russian queens and screened
bottoms.Overall health
and clean equipment , plus good management are needed.
This spring my bees are in great shape and I have started to requeen. This is
really difficult to do.What do you requeen?
I will do some splits and save some of the year old queens.
Best Regards
Roy