In the June Bee Culture Clarence Collison talks extensively about what has been learned about DWV and its transmission.  We all know, I hope, that varroa mites are a major vector of this virus.  However, it seems there is strong evidence that it can be transmitted sexually to queens via infected sperm and to offspring via infected eggs.  It seems to me that this says anyone producing queens for sale needs to have a really aggressive mite control program.  By really aggressive I mean more than normally required to run a regular commercial bee operation.  The reason is the better you control mites the lower the virus count in the queens you produce.  And, the lower the virus count in the queens the lower the virus count those queen's offspring are born with.  A queen once infected is permanently infected presumably.  So, all her offspring will be infected at birth.

Is this part of the variability we see in queens?  Is this part of the reason that a hive that has high DWV symptoms is pretty much doomed even if the mite population is knocked to zero?  Does this imply we need to think about knocking mite numbers lower thru the whole year to keep virus counts down rather than use an economic threshold mite count as the guide to what is an ok mite count?

Dick

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