Re: mite resistant queens

What I saw this year is very good resistance to varroa this year by about
80% of my colonies.  What surprised me and another buddy is the losses of
some strong colonies despite having low mite levels.

It used to be that varroa infestation needed to be fairly high to kick off
viral collapse.  Now it appears that we can lose colonies that have fairly
low mite levels in fall.  I've ruled out nosema as a suspect in many--so
that most likely leaves viruses.  I feel that mites are still associated,
since colonies that received late summer mite treatments fared better.

It is obvious to me that we've come a long way toward breeding mite
resistant queens.  Such bees greatly reduce the need for mite treatments.
However, there are more disease issues afoot than just mites alone.  In such
cases, even low mite levels may tip the balance against the bees.

Randy Oliver

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